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Full text of "JPL Quarterly Technical Review, volume 1, no. 1"

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J PL Quarterly 
Technical Review 



Volume 1 



April 1971 



Number 1 



Papers on: 

Antennas 

Biology 

Chemistry 

Computer Applications 

Electronic Components 

Lunar and Planetary Exploration 

Materials 

Power Sources 

Propulsion 

Telemetry 

Test Facilities 

Abstracts of: 

Technical Reports 
Technical Memorandums 
Space Programs Summary 
Open Literature Reporting 

C^, ''^■^^' '' '■" 
J% ^ ^ 



F!L 
CORY 



Jet Propulsion Laboratory/California Institute of Technology 



JPL Quarterly Technical Review 
Volume 1, Number 1 

Copyright © 1971 

Jet Propulsion Laboratory 

California Institute of Technology 

4800 Oak Grove Drive 

Pasadena, California 91103 

Prepared Under Contract NAS 7-100 
National Aeronautics and Space Administration 



Requests for copies of JPL publications should 
be made in writing to the attention of: Manager, 
Technical Information and Documentation Divi- 
sion Support Section 751. 



JPL Quarterly 
Technical Review 

Volume 1 April 1971 Number 1 



Contents 

1 Satellite Flyby Opportunities for the Multi-Outer-Planet Missions 
P. A. Penzo 

13 Applications of FORMAC in the Mathematics of General 
Relativity 
H. D. Wahlquist 

17 A Higher Performance Electric-Arc-Driven Shock Tube 
W. A. Menard 

29 Solid-Propellant Burning-Rate Modification 

M. F. Humphrey 

35 Low Acceleration Rate Ignition for Spacecraft 
J. I. Shafer, L. D. Strand, and F. A. Robertson 

45 Cyanate Ion and the Uremic Syndrome 
J. D. Ingham 

49 Oil-Absorbing Polymers 
H. E. Marsh, Jr. 

57 Fatigue of Teflon Bladder Bag Materials 
E. F. Cuddihy 

64 Liquid-Metal MHD Power Conversion 
D. J. Cerini 



i 



68 Design and Development of a 66-W/kg, 23-m2 Roll-Up 

, Solar Array 
W. A. Hasbach 

78 Large Spacecraft Antennas: New Geometric Configuration 
Design Concepts 
R. E. Oliver 

86 Antenna Support Structure Aperture Blockage Loss 

A. Ludwig 

97 Interplex Modulation 

S. Butman and U. Timor 

106 Calculation of Space-Charge Forces in the Analysis of 

Traveling-Wave Tubes 
H. K. Detweiler 

116 A Magnetic Tape Recorder for Long Operating Life in Space 

E. Bahm 

125 Lunar Traverse Missions 

R. G. Brereton, J. D. Burke, R. B. Coryell, and L. D. Jaffa 



Bibliography of Current Reporting 
139 Author Index With Abstracts 

280 Subject Index 
305 Publication Index 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Satellite Flyby Opportunities for the 
Multi-Outer-Planet Missions 



p. A. Penzo 

Mission Analysis Division 



In the proposed missions to the outer planets, observations of their natural 
satellites will be of considerable scientific interest. In this study, the satellite 
encounter opportunities are generated for two niultiple-flyby missions which 
include all five of the major planets. Many favorable encounter opportunities 
have been found for the large satellites of Jupiter, and some for Titan and 
lapetus of Saturn. The opportunities for satellites of Uranus are least favor- 
able. Opportunities also exist for multiple-satellite encounters on the same 
mission and examples are shown. Finally, for Jupiter, some arrival dates 
exist where very close flybys o£ certain satellites are possible. These oppor- 
tunities, added to the multiple-planet missions, will enhance their scientific 
return significantly. 



Introduction 

During the late 1970s, the favorable configuration of the outer planets 
leads to unique opportunities to fly by several of these giant planets vs'ith 
a single spacecraft. Thus, with a bit more energy than is required to get 
to Jupiter, for example, it will be possible for the spacecraft to acquire a 
gravity-assisted energy increase at Jupiter sufficient to go on to Saturn and 
then to Pluto. Several combinations of such multiple-planet missions have 
been studied in detail (e.g.. Reference 1) where Jupiter is the first planet. 
Two such combinations have received considerable attention recently 
(Reference 2) and are seriously being considered as part of NASA's 
program to explore the outer planets. These are the Jupiter to Saturn to 
Pluto (JSP) combination, which has favorable launch periods in 1976, 
1977, and 1978; and the Jupiter to Uranus to Neptune (JUN) combina- 
tion with favorable launch periods in 1978, 1979, and 1980. This study 
will concentrate on satellite encounter opportunities for two of the mis- 
sions, i.e., JSP 77 and JUN 79. 

Studies of these multiple-planet missions date back to 1966 (Refer- 
ence 3); however, very little attention was given to the possibilities of 



encountering the planets" satellites during these missions. Recently, how- 
ever, scientific interest in the satellites has increased. Typical questions 
which may be asked concern their figures, possible atmospheres, magnetic 
fields, densities, and surface properties. Close encounters with the satellites 
may resolve some of these questions and, some scientists believe, lead to 
a better understanding of the origin and evolution of the solar system. This 
study shows that very near encounters with certain satellites are possible 
during multiple-planet missions and, if some sacrifice is made in approach 
distances, multiple-satellite encounters are also possible. 



Flyby Characteristics 

Due to the increased interest in the satellites, a systematic study was 
begun at JPL within the past year to determine possible satellite encounter 
opportunities during the JSP and JUN missions. Such satelhte encounters 
require that two conditions be satisfied. The first requirement is that the 




9 14 

SEP 
EARTH LAUNCH DATES, 1977 



Figure 1. Launch and arrival times for the JSP 77 mission 



o 

< 



1 r 



1 1 n 

■ NEPTUNE ARRIVAL DATES 

■ URANUS ARRIVAL DATES 

■ DECLINATION CONSTRAINT 



C3 = 100 kmVs^ 




11 
NOV 
EARTH LAUNCH DATES, 1979 



Figure 2. Launch and arrival times for the JUN 79 mission 



flyby trajectory comes close to the orbit of the satellite of interest. This 
makes an encounter at least geometrically feasible, and will depend upon 
the flyby trajectory path relative to the satellite orbit. The second is 
that the satellite and the spacecraft be on their respective orbits at posi- 
tions where the distance between the orbits is nearly minimum. Achiev- 
ing this condition is primarily a matter of timing the spacecraft arrival 
at the planet. 

The flyby characteristics/ in turn, are dependent on the particular 
planetary mission. For example, for a JSP mission, choosing an Earth 
launch date and Jupiter arrival date will completely specify the trajec- 
tory, except for the flyby geometry at the final planet. Elements specified 
include the launch energy, the intermediate planet flyby characteristics, 
and the arrival times at Saturn and Pluto. Figures 1 and 2, for example, 
present Jupiter arrival date versus Earth launch date for the JSP 77 and 



^The data presented here has been generated with conic programs which have not 
considered oblateness or third body effects. The accuracy of these programs is quite 
sufficient for the preUminary analysis presented here. 



JUN 79 missions, respectively. Plotted- are lines of constant Earth launch 
C-s, and the outer planets' arrival times. The launch asymptote declination 
line of dzO.497 rad (±28.5 deg),^ which may limit the length of the 
launch window, is also shown. 

Several characteristics may be noted in these figures. The first is that 
the flight times to the planets will increase with decreasing €■>. These 
flight times range from 450 to 600 days for Jupiter, 2.8 to 3.5 yr for 
Saturn, and 5.0 to 7.0 yr for Uranus. The flight times to the final planets, 
Pluto and Neptune, can vary from 7.5 to 11 yr. In addition, if the arrival 
date at a given planet is held fixed for a given launch period, perhaps 
to take advantage of a close satellite encounter which may occur on that 
date, the flight times to the remaining planets do not change appreciably 
(the actual changes may be read off these curves). The Earth launch C3, 



-The value of C, (km"/s") is twice the energy per unit mass of the spacecraft after 
injection from Earth parking orbit. It is also equal to the square of the spacecraft 
hyperbolic excess velocity, V^. 

■'Where applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents the 
measured or calculated unit. 





a) 


JUPITER FLYBY 








u. lu 




I 1 1 1 1 


1 1 1 1 1 


1 




0.08 


^ 




8/20/77_ 


^::::==^ 


5 




- 




9/]4/77 




4 


0.06 




3 


0.04 




1 1 1 1 


1 1 1 1 1 


1 
















60U 




1 1 1 1 1 


1 1 1 1 1 


->V 


14 


400 


~^~ 








12 


300 


- 










?nn 




1 1 1 1 1 





— h-v» 


10 




b) 


SATURN FLYBY 








1.6 


1 


1 1 1 1 1 


1 1 1 1 1 


1 




1.4 


- 






- 


80 


1.2 


- 






- 


70 


1 .0 




1 1 1 1 1 


1 1 1 1 1 


1 - 


60 














1000 




1 1 1 1 1 


1 1 1 1 1 


1 

R " 


18 


800 


~ 






P 


16 


600 


- 










4on 




— i-—r-^i 1 1 


1 1 1 r~~~r 


— -uVoo" 


14 



31 10 20 30 9 19 1 11 21 31 10 20 30 

JAN FEB MAR APR 

JUPITER ARRIVAL DATES, 1979 



Figure 3. Hyperbolic parameters for the JSP 77 mission 



(a) JUPITER FLYBY 



0.02 






b) URANUS FLYBY 




0.14 


1 1 1 1 1 1 1 1 


III! 


0.12 


- 


- 


0.10 


. 


' ' ^ 


n OR 


1 1 1 1 1 1 1 1 


1 1 1 1 ~ 



20 


-r- — 1^1 1 1 


1 1 1 1 1 1 




00 


^^---^^ 


R 


^ 


80 


- 






60 


- 


^.--— ■'"^''^^"'"'^^^ 




40 


^ ■ — - — ■ " 






70 


1 1 1 1 1 


1 1 1 1 1 1 1 





17 27 6 16 26 6 16 26 S 15 25 S IS 

MAR APR MAY JUN JUL 

JUPITER ARRIVAL DATES, 1981 

Figure 4. Hyperbolic parameters for the JUN 79 mission 



however, will change, being a maximum at the beginning and end of the 
launch period and having a minimum near the center. 



Figures 3 and 4 present some flyby parameters for the JSP 77 and 
JUN 79 missions, respectively, as a function of the Jupiter arrival date. 
These data are nearly independent of the launch date, except for slight 
variations in inclinations (i) at Jupiter. (All inclinations are relative to 
Earth ecliptic.) At Jupiter, the values and variations in the inclination are 
small. As discussed below, this characteristic is favorable relative to close 
encounters with the satellites of Jupiter. The high inclination of the 
Saturn flyby is due to the requirement that the spacecraft go on to Pluto, 
which is considerably out of the ecliptic plane at the time of Pluto arrival. 
Included in these figures are the radial distance of the flyby periapsis 
(Rp), given in kilometers, and the hyperbolic excess velocity at the planet. 
For flyby missions, this last parameter does not play a significant role in 
the planet and satellite encounters; however, for orbital missions the 
orbit insertion fuel requirements will have a strong dependence on this 



parameter. For satellite encounters, the radial distance is important since 
it indicates how close to the satellite orbit the flyby trajectory may come. 

Satellite Encounter Opportunities 

Determining the characteristics of the flyby trajectories for the set of 
Jupiter arrival dates of interest, such as presented in Figures 3 and 4, is 
one necessary requirement for finding satellite encounter opportunities. 
In addition, it is necessary to know the characteristics of the satellite 
orbits themselves and, in fact, to know their positions as a function of 
time (their ephemerides). At present, for this and similar studies, JPL has 
implemented some long existing theories concerning the motions of the 
satellites of the outer planets. These ephemerides are sufficiently accurate 
for preliminary analyses. Anticipation of the need for greater accuracy is 
presently leading to increased activity at JPL and elsewhere to develop 
improved ephemerides for the satellites. Although the existing ephemerides 
were used to generate the encounter data presented in this study, it is 
useful to list here some of the gross characteristics of the satellite orbits. 

Table 1 presents some satellite orbital data for Jupiter, Saturn, and 
Uranus. For Jupiter only the larger (Galilean) satellites are listed. For 
Saturn, two of the larger satellites are given, and these will be discussed 
later with regard to encounter opportunities. The five satellites of 
Uranus form an extremely regular system and the characteristics of all 
of them are presented. Considerably more information may be found in 
References 4 and 5. 

Table 1. Satellite orbital data (The Ecliptic Coordinate System) 

Semi-major Inclination, Ascending Period, 

Satellite . , Eccentricity , j j j 

axis, km -^ deg node, deg days 



Jupiter 
lo 


422,000 


0.0 


2.18 


Europa 


671,400 


0.0003 


2.22 


Ganymede 


1,071,000 


0.0015 


2.02 


Callisto 


1,884,000 


0.0075 


2.01 


Saturn 








Titan 


1,222,600 


0.029 


27.74 


lapetus 


3,562,900 


0.104 


17.59 


Uranus 








Miranda 


129,800 


0.0 


98.0 


Ariel 


190,900 


0.0028 


98.0 


Umbriel 


266,000 


0.0035 


98.0 


Titania 


436,000 


0.0024 


98.0 


Oberon 


583,400 


0.0007 


98.0 



338 


1.77 


350 


3.55 


341 


7.15 


333 


16.69 


169 


15.95 


140 


79.33 


166.4 


1.41 


166.4 


2.52 


166.4 


4.14 


166.4 


8.71 


166.4 


13.46 



Jupiter 

Analyzing the characteristics of the flyby trajectories to the planets, 
and the satellite characteristics presented in Table 1, it has become evi- 
dent that conditions for satellite encounter are much more favorable at 
Jupiter than at Saturn and Uranus. (Pluto has no known satellites, and 
the Satellites of Neptune may be targeted to since it is the last planet 
of the JUN mission.) Figure 5 presents the sets of flyby trajectories for 
the JSP 77 and JUN 79 missions and indicates that the flyby trajectories 
will lie very close to the plane of Jupiter's equator and hence to the plane 
of the satellite orbits. The earlier arrival date has been chosen on the 
basis that the total mission time is about 8 yr. The later arrival date 
assumes a total mission time of no more than 10 yr. The view in Figure 5 
is from the ecliptic north pole. The inclinations of the flybys are all less 
than 0.1 rad (6 deg) to Jupiter's equator. Another favorable aspect of 
these trajectories is that their periapsides lie within the orbits of many 
of the satellites. Thus, the first condition for favorable satellite encounters 
is satisfied. Also, since the periods of these satellites are short (about 
16 days for Callisto), compared with the range of possible arrival dates 
(about 3 months), there exist many Jupiter flyby times such that encoun- 
ter with any given satellite is possible. 

Based on the simplifying assumptions that the flyby trajectories are in 
the plane of the satellite orbits and that these orbits are circular (all 



(JUPITER ARRIVAL DATE) 




JSP 77 



Figure 5. Sets of flyby trajectories for the JSP 77 and JUN 79 missions 



eccentricities are less than 0.01), it is possible to generate satellite en- 
counter times to an accuracy of about 0.1 day. (Actually, what is found 
is the Jupiter flyby time of closest approach which will produce an en- 
counter with a given satellite.) This was done for the range of Jupiter 
arrival dates of interest. In determining the encounter times, the varia- 
tion of the flyby altitude, energy, and orientation with the arrival date 
is taken into account. With these approximations as first guesses, it is a 
simple matter to calculate the exact encounter time and encounter char- 
acteristics with computer programs in which no simplifying assumptions 
are made. 



Once these approximate single-satellite encounter opportunities have 
been generated, it is straightforward to find multiple-satellite encounters. 
Specifically, the data for single-satellite encounters consist of a list (for 
each satellite) of flyby periapsis times for which encounter with that 
satellite will occur. This list contains two sets, the first comprising those 
times for which encounter will occur prior to periapsis passage, and the 
second those times for which encounter will occur after periapsis passage. 
For multiple-satellite encounters, it is only necessary to scan the lists for 
all the satellites to find when the times are nearly coincident. For exam- 
ple, it may be found that a flyby periapsis passage on February 3.4, 1979, 
will result in an encounter with Europa prior to periapsis passage, 
whereas a periapsis passage on February 3.5, 1979, will result in an 
encounter with lo after periapsis passage. Thus, by compromising the 



CALLISTO 




TO SUN 
TO EARTH 



Figure 6. Possible Jupiter flyby with multiple-satellite encounters 



periapsis time and targeting for a periapsis passage of February 3.45, 
1979, it is possible to encounter both satellites, although some sacrifice 
in the closest approach distance to the two satellites will have to be 
made. Of course, the scan may (and does for JSP 76, as discussed in 
Reference 2) yield an opportunity to encounter all four of the Galilean 
satellites. 



For the JSP 77 mission, several favorable multiple-satellite encounters 
exist for lo, Ganymede, and Callisto. The most favorable is shown in 
Figure 6, where the flyby periapsis time is March 5.3, 1979 GMT. For 
this case, the flyby periapsis is inside, but close to, Jo's orbit, and en- 
counter with lo (at a distance of about 40,000 km) occurs just prior to 
periapsis passage. Encounters with Ganymede and Callisto occur after 
periapsis passage with closest approach distances of about 50,000 and 
130,000 km, respectively. Lighting conditions for viewing the three satel- 
lites is favorable. 



Saturn 

The method of analysis to generate the satellite possibilities and times 
that were used on Jupiter cannot be directly applied to Saturn. The 
reason is that the flyby trajectories are highly inclined to the ecliptic 
plane; about 1.3 rad (75 deg) for the JSP 77 mission as may be seen in 
Figure 3. On the other hand, most of Saturn's satellites are very close to 
the plane of the rings, which is inclined about 0.49 rad (28 deg) to the 
ecliptic. Thus, the flyby trajectories will be highly inclined to the satellite 
orbits. The first condition, then, that the flyby trajectory comes close to 
the satellite orbit, is less likely to be satisfied than for Jupiter, where the 
flyby trajectory and the satellite orbits are nearly coplanar. 



SATURN (AND 

ITS RINGS) - 

SPACECRAFT AT 

TITAN ENCOUNTER 

(400,000 km) 




SPACECRAFT AT 
lAPETUS ENCOUNTER 
(60,000 km) 



Figure 7. Possible Saturn flyby with multiple-satellite encounters 



A preliminary analysis has been performed for the JSP 77 mission 
considering the possibilities of encountering the two larger satellites of 
Saturn, Titan, and lapetus. Considering the out-of-plane condition, the 
possibilities are good. For Titan, the closest approach distance is about 
400,000 km, and for lapetus, about 60,000 km. Further, scanning the 
encounter times for Saturn arrivals ranging over a 6-mo period, a mul- 
tiple encounter for Titan and lapetus was found, where the closest 
approach distances are close to the values given above. The encounter 
opportunity is presented in Figure 7, as viewed from Saturn's north pole, 
where the time of periapsis passage is November 13.8, 1980 GMT. 
Because of the high inclination, there is no occultation of the spacecraft 
with Saturn as seen from Earth. This opportunity is rare because of the 
long period (79.3 days) for lapetus. 

Considering that Saturn has 10 known satellites, 7 of which have esti- 
mated radii, much of the analysis of encounters with these satellites 

lies ahead. 

Uranus 

For Uranus, which is considered in the JUN 79 mission, analysis of 
the flyby trajectory indicates that its plane is practically normal to the 
plane of the satellite orbits (all five of which lie in the plane of Uranus' 
equator and have near-zero eccentricity). In this extreme situation, a 
good approximation to the closest possible approach distance is simply 
the difference between the periapsis distance of the flyby trajectory 
and the semi-major axis of the satellite orbit. Referring to Figure 4, it 
is seen that the flyby periapsis distance is always less than the semi- 
major axis of Miranda (see Table 1), the innermost satellite of Uranus. 
Since the flyby altitude distance increases with flight time, the more 
favorable encounters will occur for the longer flight times (assuming 
that the time of periapsis is correctly chosen). A favorable aspect of the 
Uranus satellite encounter problem is the fact that the inner three 
satellites have short orbital periods (less than 5 days) allowing greater 
flexibility in timing the encounters, and possibly the performance of a 
midcourse maneuver to improve the encounter time. 

Summary 

The existence of favorable satellite encounter opportunities is most 
strongly dependent upon the geometric relationship between the flyby 
trajectory and the orbit of the satellite considered. For the JSP 77 and 
JUN 79 missions, this relationship at Jupiter is favorable. Thus, many 
encounter possibilities with the Jupiter satellites exist. For Saturn, the op- 
portunities are less favorable, and for Uranus, they are quite unfavorable. 

For Jupiter, with the approximate assumptions that the sets of flyby 
trajectories (Figure 5) are in the plane of the satellite orbits, and that 



10 



these orbits are circular, it has been possible to exhaustively determine 
the satellite encounter times. Essentially, these encounter times will 
occur twice during each revolution of the satellite, e.g., twice every 
1.77 days for lo. Multiple-satellite opportunities are obtained by merely 
scanning the results and determining if there are several favorable en- 
counters for the same flyby periapsis arrival time at Jupiter. Once these 
opportunities are found, a detailed analysis, utilizing the precise flyby 
trajectory and ephemerides of the satellite orbits, may be performed such 
as was done for the example given in Figure 6. 

The encounter distance given in Figure 6 includes an out-of-plane 
component and, it is clear, that since the flyby trajectory characteristics 
change with Jupiter arrival date, this out-of-plane miss will also change. 
Analyzing the geometry more closely, it has become evident that this 
minimum distance can become quite small for certain satellites. This 
occurs when the flyby trajectory passes through the satellite orbit plane 
at the same time that it encounters the satellite. For JSP 77 this can 
occur for Ganymede before periapsis passage, and for lo and Europa 
after periapsis passage. For JUN 79, a near-zero encounter distance can 
occur for lo and Europa after periapsis passage. Determination of these 
closest approach times and the precise distance of these approaches has 
not been determined as yet; however, these times may offer opportunities 
to study a single satellite very closely, including possible occultations 
with Earth. 

In summary, even with the trajectory restrictions which the multiple- 
planet missions impose, there exist possibilities to increase the scientific 
return and make these missions even more attractive by including close 
flybys with satellites. 



References 

1. Wallace, R. A., "Missions to the Outer Planets," in Supporting Re- 
search and Advanced Development, Space Programs Summary 37-54, 
Vol. Ill, pp. 35-36. Jet Propulsion Laboratory, Pasadena, Calif., 
Dec. 31, 1968. 

2. Bourke, R. D., Friedman, L. D., Penzo, P. A., and Stavro, W., "Design 
of Grand Tour Missions," AIAA Paper 71-187, presented at the AIAA 
9th Aerospace Sciences Meeting, New York, N. Y., Jan. 25-27, 1971. 

3. Flandro, G. A., "Fast Reconnaissance Missions to the Outer Solar Sys- 
tem Utilizing Energy Derived from the Gravitational Field of Jupiter," 
Astronaut. Acta, Vol. 12, No. 4, 1966. 



11 



References (contd) 

4. Melbourne, W. G., MulhoUand, J. D., Sjogren, W. L., and Sturms, 
F. M., Jr., Constants and Related Information for Astrodynamic Calcu- 
lations, 1968, Technical Report 32-1306. Jet Propulsion Laboratory, 

Pasadena, Calif., July 15, 1968. 

5. Newburn, R. L., Jr., A Brief Survey of the Major Planets: Jupiter, 
Saturn, Uranus, and Neptune, Technical Memorandum 33-424. Jet 
Propulsion Laboratory, Pasadena, Calif., Apr. 1, 1969. 



12 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Applications of FORMAC in the Mathematics of 
General Relativity 

H. D. Wahlquist 
Space Sciences Division 



The use of FORMAC (formula manipulation by computer) to perform 
symbolic analysis on the computer in the field of general relativity is de- 
scribed. FORMAC will accept symbolic analytical expressions involving 
complex algebraic functions, elementary transcendental functions, user- 
defined functions, and unspecified functions of any number of dependent 
variables. In particular, FORMAC programs have now been written to 
implement the noncommutative calculus of exterior differential forms. 
Applications of this new capability to Hamiltonian cosmology and the 
theory of partial differential equations are discussed. 



Introduction 

In recent months the IBM FORMAC (formula manipulation by com- 
puter) system has become available at JPL for use with the IBM 360-75 
computer. The present version of FORMAC is imbedded in the PL/1 
programming language and represents a considerable improvement over 
the original FORTRAN version that was developed in 1965. FORMAC 
will accept symbolic analytical expressions involving complex algebraic 
functions, elementary transcendental functions, user-defined functions, 
and unspecified functions of any number of dependent variables. Instruc- 
tions are available to manipulate these expressions algebraically, make 
substitutions and evaluations, take partial derivatives of any order, an- 
alyze the structure of generated expressions, print out results in an edited 
form (with raised exponents, for example) which is quite close to stan- 
dard algebraic format, and punch intermediate expressions on cards in 
an appropriate form for later input. 

The system performs a great deal of automatic simplification of ex- 
pressions as they are generated. All transformations requiring the factor- 
ing of an expression, however, are under control of the user and not done 
automatically. As a result many elementary simplifications are missed if 



13 



not specifically programmed. In a complicated program this can lead to 
an explosive growth in the length of expressions, rapidly filling all 
available core. This is the major difficulty in using FORMAC and can 
be a serious drawback. However, our experience has been that it can 
usually be handled by careful and sometimes incremental programming. 



Applications in General Relativity 

The mathematics of general relativity is an excellent example of a field 
in which a large amount of tedious, time-consuming, and error-prone 
analysis must be performed. The prototypical problem is the derivation 
of the Christoffel symbols and Riemann tensor components from a given 
metric tensor. A number of FORMAC programs to accomplish this task 
have been written by users in the past few years; it is a straightforward 
and very satisfactory application of FORMAC. 

The search for exact solutions of the field equations of general relativ- 
ity, however, often requires less straightforward, but still very lengthy, 
analysis and several specialized FORMAC programs to aid in accom- 
plishing this work have now been developed. Most recent investigations 
in this area involve the use of modern coordinate-independent formula- 
tions of general relativity such as exterior differential forms and the 
closely related tetrad formalisms, one of the latter being the dyadic 
formalism originated at JPL. 



Differential Forms and the EXTCALC Subroutines 

Actually, the language of exterior differential forms has found wide 
application in various fields of mathematics and theoretical physics other 
than general relativity. Examples are: Hamiltonian mechanics, differen- 
tial geometry, and the general theory of sets of partial differential equa- 
tions (see Reference 1). FORMAC is not immediately competent to deal 
with this language, which involves noncommutative operations. Recently, 
however, a set of PL/1 FORMAC subroutines (the EXTCALC package) 
was developed by F. Ernst of the Illinois Institute of Technology to 
implement this capability for calculations in general relativity. In col- 
laboration with Professor Ernst, we have now extended the original 
EXTCALC package to incorporate additional operations so that it is no 
longer limited to a specific application, but is capable of performing 
virtually all the analytical operations of the exterior calculus of differ- 
ential forms. Thus, quite general problems can now be formulated in 
this language and analyzed on the computer. 

A thorough description and user's manual for the original EXTCALC 
package can be found in Reference 2, and only a brief summary of the 



14 



extended package is presented here. The specific operations of the exte- 
rior calculus implemented within the present EXTCALC package are: 



Operation Subroutine name 
Exterior product HAT 

Vector contraction CONTRACT 

Exterior derivative D or (@) 

Lie derivative LIE 



One writes any symbolic differential form expression containing these 
operations (which may be nested) as a character string argument of the 
master subroutine #LET, in direct analogy with standard FORM AC 
statements. This master routine then directs the processing of the ex- 
pression, calling the necessary operational subroutines, until a correct 
expression, interpretable by standard FORMAC, is created and returned. 
Several other convenient (though unessential) operations can also be per- 
formed within #LET. Thus, for example, one can order differential form 
expressions into a specified format, extract the coefficient of any basis 
form, and switch to a new set of basis forms. 



Several diverse applications of this capability have been made in recent 
months. Within general relativity we have used the EXTCALC package 
to aid in developing a unified Hamiltonian theory of a class of homoge- 
neous, anisotropic cosmological models— those with symmetry groups of 
Bianchi types VIII and IX. The differential geometry of such spaces is 
best treated in differential form language with anholonomic basis forms 
adapted to the appropriate symmetry group, which is an ideal application 
of the formalism. 



Another application has been to perform some of the calculations in- 
volved in deriving symmetry groups of partial differential systems. Here 
again, as shown in the work reported in Reference I, the use of differ- 
ential forms permits the most elegant and concise formulation of the 
general theory of symmetry properties of sets of partial differential equa- 
tions. In this approach the equations for the generators of the symmetry 
group are expressed in terms of the Lie derivatives of a set of exterior 
differential forms equivalent to the set of partial differential equations. 
To work out the content of these equations in a complex case can require 
a considerable amount of analysis. Using the FORMAC-EXTCALC ca- 
pability for Lie differentiation of forms, it is now a simple matter to de- 
sign a program (ISOVECT) to accomplish the analysis on the computer. 



15 



References 

1. Harrison, B. K., and Estabrook, F. B., "Geometric Approach to Invari- 
ance Groups and Solution of Partial Differential Systems," /. Math. 

Phys., Vol. 12, Feb. 1971 (in press). 

2. Ernst, F. J., "Manipulation of Differential Forms on a Digital Com- 
puter," in Proceedings of the Relativity Seminar, Illinois Institute of 
Technology, Chicago, 111., Sept. 1969. 



16 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



A Higher Performance Electric-Arc-Driven 
Shock Tube 



W. A. Menard 

Environmental Sciences Division 



The results of an experimental study made to improve the performance of 
electric-arc-driven shock tubes are presented. With only minor modifications 
to the driver, shock velocities have been increased by a factor of 3. The nevif 
driver has a conical internal design of small volume, and uses a light-weight 
diaphragm which disintegrates during the electrical discharge. Data obtained 
from a 15.2-cm-diameter driven tube, 11.3 m in length, show little shock 
wave attenuation in gases simulating the Jupiter and Saturn atmospheres. 
Shock velocities of 45 km/s with test times in excess of 4 /is have been 
attained. Because of the extended performance, the electric-arc-driven shock 
tube may now be used to study many outer-planet atmospheric entry 
problems. 



Introduction 

To study Jupiter and Saturn atmospheric entry problems in the labora- 
tory requires a facility capable of producing shock velocities from 25 to 
48 km/s. The purpose of this article is to report on the modifications 
made to the JPL shock tube, which have increased velocity vi?ell into the 
outer-planet entry range. An experiment was designed to investigate per- 
formance over a wide range of driver energies, and initial pressures from 
6.66 to 6660 N/m- (0.05 to 50 torr).^ Measurements of shock velocity, 
shock wave attenuation, and test time were made in several test gases. 

Facility 

The JPL electric-arc-driven shock tube was originally designed with a 
3.5-cm-diameter driver, 66 cm long (Reference 1). A later design (Refer- 
ence 2) provided for a variable length and increased the diameter to 



^Where applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents the 
measured or calculated unit. 



17 



15.2 cm. Energy for the driver is supplied by a 100-capacitor (14.5 jiF) 
storage system, rated at 290,000 J when charged to 20,000 V. 

The new driver, which was designed from the driver of Reference 2 
with only minor modifications, is shown in Figure 1. The cathode is a 
3.2-cm-diameter cylinder made from Mallory 1000 (a sintered tungsten 
alloy). A hole in the cathode tip allows the trigger wire to be pulled 
through. The anode is a 2.5-cm-wide, 7.6-cm-diameter copper ring lo- 
cated 9.6 cm from the cathode. A conical Teflon insert reduces the 
driver volume to 350 cm^, and provides a fairly smooth internal contour 
from the cathode tip to the 15.2-cm-diameter driven tube. The half angle 
of the cone is approximately 217 mrad (12.5 deg). The diaphragm is 
located on the downstream side of the anode ring. A 0.025-cm-diameter 
stainless steel wire is strung across the opening, and the trigger pull wire 
is attached to this wire. In operation, the arc is initiated by puUing the 
trigger wire toward the cathode. 

In order to reduce diaphragm opening losses and to insure a fast open- 
ing time, Mylar diaphragms (0.035 cm thick) are used. Hehum or hydro- 
gen gas is supplied to the driver at a pressure of 1.19 X 10'' N/m- 
(11.8 atm), just 4% less than the static rupture pressure of the diaphragms. 

When the arc is struck, the trigger wires and the diaphragm immedi- 
ately disintegrate. It was found that at high driver energies the copper 
anode could not hold the arc. Severe erosion on the surface of the stain- 
less steel transition section was evidence that the arc had extended 7 cm 
beyond the diaphragm. Current measurements of the capacitor bank dis- 
charge show the arc burns for about 25 ^s. During this time the driver 



COPPER ANODE 
DIAPHRAGM 



TEFLON INSERT 

■ MALLORY CATHODE 




CERAMIC LINER-^ PULL ROD- 

Figure 1. Schematic of driver configuration 



IS 



gas can receive energy from the arc while in the driver, and as it expands 
down the tube. 

Erosion of the cathode and copper anode was minimal. Replacing the 
transition section with one made of copper would reduce erosion there 
and improve electrode efficiency. 



Shock Velocity Measurements 

The most abundant elements in the atmospheres of Jupiter and Saturn 
are believed to be hydrogen and helium. For this reason the majority of 
the shock tube runs were made in a mixture of 80% He and 20% H, 
(by volume). 

The driven tube was 11.3 m long and had instrument ports arranged 
to measure shock velocity [/« at distances L from the diaphragm of 2, 
3.66, and 10.67 m. Shock speeds were measured by viewing the shock 
front radiation with collimated photomultipliers spaced 61 cm apart. 



20- 









1 


1 






1 
O 










EMPIRICAL FIT— X 
D 






O 




/ 

D 


D 


D 


■ 






He/0.8 He -0.2 H2 

P =33.3 N/m^ 
(0.25 torr) 








I 


1 




O 

D 
■ 


L, m 

3.66 
10.67 
10.67 (SEE TEXT) 

1 



100 200 

CAPACITOR BANK ENERGY, kJ 

Figure 2. Variation in shock velocity with energy input 



19 



Velocities were measured to an approximate accuracy of ±3%. The tube 
was cleaned and pumped to 0.06 N/m- (0.5 p.) or less before each run. 

Shock velocities obtained in 33.3 N/m- (0.25 torr) of the test gas, over 
a range of driver energies from 26,000 to 290,000 J, are presented in Fig- 
ure 2. The driver gas was helium, and the data were taken at 3.66 and 
10.67 m from the diaphragm. Velocities were obtained from 12 to over 
32 km/s. They are seen to increase continuously as energy is increased 
with no indication of leveling off. If more energy were available, it would 
appear that even higher speeds could be reached. 

The dark data point at L = 10.67 m was taken with one-fourth of the 
capacitor bank disconnected to investigate the effect of driver voltage on 
performance. No significant effect was observed. 

The effect of initial pressure on performance is shown in Figure 3. 
Pressure was varied from 6.66 to 6660 N/m=^ (0.05 to 50 torr) while hold- 



„3 _ 



- 


1 1 1 
D O 


1 \ 


1 


1 1 




. 




\ 


. 


EMPIRICAL THEORY 










\r 


L = 3.66 m 


- 


- 


P 





\ 






- 




no 


00 


\ 


- 


- 


He/0.8 He -0.2 H2 






\ 






E = 290,000 J 






\ 






L = 3.66 m 




11 III 


000 




- 


D L = 10.67 m 






\ 




- 








1 III 1 ccpo 




- 


1 1 J 


1 


1 


1 1 


_. 



4 8 12 16 20 24 28 

SHOCK VELOCITY, km/s 

Figure 3. Shock velocity/initial pressure performance 
20 



ing energy constant. Attenuation of the shock wave is less at the lower 
pressures. Over a distance of 7 m, the lowest pressure data shows an 
attenuation of only 10%, but at pressures of 666 and 6660 N/m^ (5 and 
50 torr), the attenuation is 35%. 



Other Gases 

Runs were also made in pure hydrogen, helium, air, and argon, using 
helium and hydrogen driver gases. A summary of results is presented in 
Table 1. Shock velocity and test time data at two tube locations are 
given. The test times, in fxs, are in parentheses. Where times are not 
shown, it is because the shock front had not completely formed. 

Shock velocities, in general, decrease as molecular weight of the test 
gas increases. With a helium driver, shock speeds in the light gases are 
greater than 30 km/s, and in the heavy gases. Us > 20 km/s. A further 
increase in shock velocity is obtained when hydrogen is used as the driver 
gas. Hydrogen-driven shock waves as fast as 45 km/s have been pro- 
duced. Higher speeds were also obtained in the heavy gases, but they 
are accompanied by stronger attenuation. 

Hydrogen is obviously more efficient in accepting electrical energy 
and converting it into flow energy, and damage to the driver verified its 



Table 1. Shock velocity, test time, and equilibrium temperature for several driver 
and driven gases, measured at two distances from the diaphragm^i 



Driven 


Heliiun 
driver gas 


Hydrogen 
driver gas 


Temperature,'' 
K 


gas 


3.66 m 


10.67 m 


3.66 m 


10.67 m 


Hydrogen 


- 


- 


45.0* 
(4-7) 


39.5 
(6) 


12,300 


0.2 H2-O.8 He 


30.8 

(5) 


28.4 
(7) 


41.3* 
(4) 


40.4 
(6) 


22,000 


Helium 


34.4* 
(4) 


28.9 
(6) 


- 


- 


21,000 


Air 


27.9* 
(7) 


23.1 
(11) 


32.7 


20.3 
(11) 


31,000 


Argon 


25.7 


20.0* 
(12) 


31.7 


15.8 

(12) 


34,700 



"Shock velocity in km/s, test time (in parentheses) in fis; initial driven gas 
pressure = 6.66 N/m^ ( 0.05 torr ) ; capacitor bank energy = 2.9 x 10° J. 

•"For velocities with asterisk. 



21 



efficiency in absorbing energy. After several runs the Teflon insert had 
developed deep holes near the cathode and required replacing. The holes 
were apparently burned by a much hotter plasma than was generated 

in helium. 

The final column in Table 1 shows the equilibrium temperatures calcu- 
lated (Reference 3) for the asterisked data. These temperatures are ex- 
tremely high for incident shock waves. In fact, comparable temperatures 
have not been produced in the reflected waves of other conventional 

shock tubes. 



Test Time Measurements 

Test time is the time interval between passage of the shock front and 
the contact surface at a point on the shock tube. Three types of measure- 
ments were made to determine test times: (1) wide-band-pass radiation 
measurements from the sidewall, (2) narrow-band-pass measurements 
from the sidewall, and (3) heat transfer measurements on a model located 
on the tube center line. Wide-band radiation was observed with a col- 
limated photomultiplier having an S-11 (visible) response. The narrow- 
band measurements were made with a photomultiplier viewing the gas 
through a 5-nm (50-X) half-width, narrow-band-pass filter. The center 
wavelength was selected to coincide with the intense Ha line (656.3 nm). 
As the test slug passed the viewing station, radiation from hydrogen 
would disappear upon arrival of the helium driver gas. Two calorimeter 
heat transfer measurements were made to verify the results from the 
radiation techniques. Both measurements showed a linear slope of the 
output which is typical of constant stagnation point heating. The tem- 
perature change at the contact surface was recorded as an abrupt voltage 
change in the gauge output. 



Radiation Profiles 

Oscillograms of strong shock waves in 6.66-N/m- (0.05 torr) test gases 
are shown in Figures 4 and 5. The top traces are narrow-band intensity 
j)rofiIes, I^-b, and the bottom traces are wide-band profiles, Iwb- Absolute 
intensity calibrations were not made but in each record the voltage out- 
puts from I.v;; were much less than the outputs from Iwb- 

The oscillogram in Figure 4a is from a 30.5-km/s shock in the 0.8He- 
O.2H2 mixture. Identified on the narrow-band trace are the shock front, 
the atomic nonequilibrium overshoot, the equilibrium level, and fi- 
nally the termination of the test time by arrival of the contact surface. 
The equilibrium level is highly ionized, consequently there should be 
little Ha radiation. The radiation observed may be from the He+ 656.0-nm 



22 



(°) 



NB 



0. 8 He-0. 2 H^ 



U = 30. 5 km/s 



T^ = 18,000 K 



WB 



EQUILIBRIUM 



SHOCK FRONT 




■, .V 



■lO/is 



CONTACT SURFACE 



EQUILIBRIUM 



SPECIES cm 



9x 10 



He 



He 



1 X 10 



7x 10" 



3x 10 



-ATOMIC NONEQUILIBRIUM 
OVERSHOOT 



(b) 



T 



MB 



T 



WB 



0. 8 He-0. 2 H„ 



38. 1 kro/s 



T^ = 20, 700 K 



- 5^s 






' r ■■"■■■ ■'■■■^■■-'-XJi'Mi^LM'MM^rS^^ 



H 
He 
H+ 
He* 



5 X 10 



6x 10 



9x 10 



1 X 10' 



13 



ONIZATION ^ EQUILIBRIUM 

Figure 4. Narrow- and wide-band oscilloscope traces for 0.8 He-0.2 H, mixture 



23 



(a) 





He 


u 

s 


= 28. 9 km/s 


T, 


= 19, 100 K 




EQUILIBRIUM LEVEL 



• ATOMIC NONEQUILIBRIUM 
OVERSHOOT 



EQUILIBRIUM 



1 X 10 



1 X 10 



16 



(b) 



AIR 
U = 20. 3 km/s 



T = 23, 000 K 



NB 



WB 



■ EQUILIBRIUM 



-IONIZATION PROCESSES 






i^i£:ili.i 






■20^s 



1 X 10 



14 



3x 10 



16 



2x 10 



9x 10 



I X 10 



1 X 10 



15 



-ATOMIC OVERSHOOT 

Figure 5. Narrow- and wide-band oscilloscope traces for He and air 



24 



(6560 A) line, and the continuum. Increasing shock velocity to 38.1 km/s 
produces the profiles shown in Figure 4b. At this temperature the equi- 
librium composition is even more highly ionized. The sustained high level 
of equilibrium radiation may again be due to the continuum and He* 
line. Note that the helium ion number density has increased by a factor 
of 3 over the 30.5-km/s data. The narrow-band intensity drops sharply 
at the interface with the driver gas. 

In Figure 5 are shown data for helium and air. Helium looks similar 
to the O.SHe-O.EH, data. From the air trace it appears that several ion- 
ization processes are seen in the approach to equilibrium. In other runs 
these processes were observed to smooth out and the equilibrium level 
increased as temperature increased. At a temperature of 28,500 K the 
overshoot had disappeared and the intensity remained constant from 
the shock front to the interface. 

The arrival of the contact surface is not obvious on most of the wide- 
band intensity data but is shovsm clearly when observed through the Ha 
filter. Tests made with H2 driver gas did not alter the appearance of the 
test slug radiation profiles. 



Correlation of Test Time (Measurements 

Some of the test time measurements are given in Table 1. Test times 
greater than 4 /iS were obtained for all test conditions of the experiment, 
and if our interpretation of the radiation profiles is accurate, equilibrium 
was established in most cases. 



An attempt to correlate the data with the boundary layer theories of 
Mirel (References 4 and 5) was unsuccessful. Laminar theory predicts 
"infinitesimal" test slug lengths at our Mach numbers and pressures. If 
one arbitrarily applies turbulent theory, lengths equal to about 25% of 
those measured are calculated. Similar results have been obtained by 
F. Livingston of this Laboratory in a pressure-driven shock tube operated 
at very low initial pressures. He was able to correlate his unpublished 
data, however, by considering two-dimensional effects. 

The present measurements were correlated to the time it takes a dis- 
turbance originating at the wall to reach the center of the tube. Plotted 
in Figure 6 are the calculated times, tc = r/as, versus the measured test 
times, T„„ for all data having 17,, > 18 km/s. (The radius of the tube is r 
and a-i is the speed of sound.) Data for the five test gases and three initial 
pressures are shown. Even though there is large scatter, the general 
agreement is good. It would appear that more theoretical work is needed 
to better understand two-dimensional effects in shock tube flows. 



25 



U > 18 km/s 

V H2 

O 0.8 He -0.2 H, 

A He 

D A!r 

O Ar 



SYMBOL P., N/r 




OPEN 6.66 
CLOSED 33.3 
HALF CLOSED 133.3 






A 


D 

a 


a 
/ 


A 
O 


-,o/ 


^ 



Figure 6. Correlation of test time measurements 



26 



Comparison With Other Facilities 

A comparison with performance from other shock tubes is made in 
Figure 7. The present results are plotted for driven tube lengths from 2 
to 10.67 m. The shock velocities exceed all other driving techniques ex- 
cept the electromagnetic driver. The modest attenuation is comparable 
to the combustion, piston, electrical, and tvi?o of the implosion drivers. 



ELECTROMAGNETIC, PINCH 




JPL ELECTRICAL 



2" 



IMPLOSION, GAS COMPRESSION 



IMPLOSION, JETTING 
O 



IMPLOSION, GAS-DETONATION 
ELECTRICAL 




ELECTROMAGNETIC, T TUBE 



ELECTRICAL 
D □ 

„ PISTON 



Figure 7. Comparison of present JPL performance with other driving techniques 



References 

1. Collins, D. J., Livingston, F. R., Babineaux, T. L., and Morgan, N. R., 
Hypervelocity Shock Tube, Technical Report 32-620. Jet Propulsion 
Laboratory, Pasadena, Calif., June 15, 1964. 

2. Williard, J. W., "Performance of a Ceramic-Lined 6-In.-Diameter Arc 
Driver," Paper 68-366, AIAA 3rd Aerodynamic Testing Conference, 
1968. 

3. Menard, W. A., and Horton, T. E., Shock-Tube Thermochemistry 
Tables for High-Temperature Gases: Vol. I. Air, and Vol. III. Helium, 
Neon, and Argon, Technical Report 32-1408. Jet Propulsion Laboratory, 
Pasadena, Calif., Nov. 1, 1969 (Vol. I) and Jan. 1, 1970 (Vol. III). 



27 



References (contd) 

4. Mirels, H., "Test Time in Low Pressure Shock Tubes," Phys. Fluids, 

Vol. 6, No. 9, p. 1201, 1963. 

5. Mirels, H., "Shock Tube Test Time Limitation Due to Turbulent Wall 
Boundary Layer," AIAA }., Vol. 2, No. 1, p. 84, 1964. 



28 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Solid-Propellant Burnirig-Rate Modification 

M. F. Humphrey 

Propulsion Division 

Low acceleration is one of the requirements for solid-propellant orbit 
insertion motors for future outer-planetary missions. This article describes 
the research accomplished in reducing the low-pressure burning rates of 
modified solid propellants. Techniques developed with the saturated 
hydroxy-terminated polybutadiene system were successfully applied to the 
polyether system (JPL 540) and an unsaturated hydroxy-terminated poly- 
butadiene propellant system. Burning-rate reductions up to 50% were ob- 
tained by the synergistic effects of increased oxidizer size, reduction of iron, 
and inclusion of flame retardants and endothermic combustion modifiers. 



Introduction 

spacecraft design studies at JPL, for future outer-planetary missions, 
have shown that low acceleration is one of the requirements for solid- 
propellant orbit insertion motors. A prerequisite for achieving these low- 
acceleration, high-performance solid-propellant spacecraft motors is the 
development of very low burning rate propellants with specific impulses 
equal to or better than the JPL 540 propellant. This work was con- 
ducted to investigate applicable methods of producing the necessary 
low-propellant burning rates without seriously degrading the efficiency 
of the combustion process. The study was concerned, primarily, with 
tailoring existing propellant formulations and, secondarily, with develop- 
ing general techniques adaptable to alternate binder compositions. 

Burning-rate tailoring began by studying the effects of modifications 
to the following propellant formulations: saturated hydroxy-terminated 
polybutadiene (SHTPB), polyether-polyurethane (JPL 540), and unsatu- 
rated hydroxy-terminated polybutadiene (UHTPB). These propellant 
systems were developed at JPL. The modifications investigated were 
oxidizer particle size, cure catalysts, binder ingredient alterations, and 
inclusion of combustion modifiers. The modified formulations of each 



29 



propellant system were mixed in 2-kg batch sizes in a 3785.4-cm^ (1-gal)^ 
Bramley mixer. The propellant batches were cast into Crawford bomb 
and soda straw burning-rate strands and physical property tensile bar 
molds. Based on the planetary mission low-acceleration requirements, an 
absolute combustion pressure of 68.9 N/cm- (100 psi) was chosen as the 
comparable parameter for the development. 

Saturated Hydroxy-Terminated Polybutadiene System 

An existing propellant system utilizing an SHTPB binder was the first 
system studied as a low burning rate propellant candidate. This propel- 
lant was selected since the standard formulation already had an inher- 
ently lower burning rate than JPL 540. This SHTPB binder, called 
Telagen S, was produced by the General Tire and Rubber Company. 
The propellant was modified by combinations of increased oxidizer 
particle size, an organo-phosphate flame retardant, and a low concentra- 
tion of a gas producer. The results of these modifications indicated that 
the burning rate was lowered from a standard of 0.24 to 0.13 cm/s (0.094 
to 0.052 in./s) at absolute pressure 68.9 N/cm- (100 psi). At the same 
time, changes in physical properties occurred, that is, the tensile strength 
decreased from a standard of 198.6 to 134.5 N/cm- (288 to 195 psi), and 
the elongation increased from a standard of 35 to 44%. 

Since the SHTPB propellant system cures at 377.6 K (220 °F) for five 
days, a study was performed to lower these cure conditions. Utilizing 
polymerization catalysts, a more rapid low-temperature cure of 300-305 K 
(80-90 °F) for two days was obtained with small concentrations of ferric 
acetoacetonate (FeAA). However, it was found that the FeAA promoted 
increased burning rates. Examination of other organo-metal compounds, 
as potential cure accelerators, indicated that vanadium acetoacetonate 
(VaAA) would give the desired cure without alteration of the propellant 
burning rate or mechanical properties. 

Soluble unreactive binder additives were also evaluated. The materials 
studied included: tri (bromo propyl) phosphate, tri cresyl phosphate 
(TCP), dihydro ethoxy trimethyl quinoline (ethoxyquin), octyl diphenyl 
phosphate (ODDP), and isodecyl diphenyl phosphate (IDDP). Only the 
IDDP was found to be effective in reducing the burning rate at a low 
concentration of 1%. 

Polyether-Polyurethane System 

Since JPL 540 propellant is well understood, it was also selected as a 
low-acceleration candidate propellant. The burning rate for the standard 



^Where applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents 
the measured or calculated unit. 



30 



propellant formulation is 0.356 cm/s (0.140 in./s) at absolute pressure 
68.9 N/cm- (100 psi). Modifications were made to this propellant system 
which resulted in a reduction of the maximum burning rate to 0.229 cm/s 
(0.090 in./s) at absolute pressure 68.9 N/cm- (100 psi). The modifications 
made were as follows: 

(1) The average oxidizer particle size was increased from 185 to 340 ^m. 

(2) One percent of an organo-phosphate flame retardant was added. 

(3) Regular aluminum powder (2000 ppm iron) was replaced with an 
essentially iron-free aluminum (20 ppm iron). 

(4) Two percent oxamide was added. 

Based on the data generated from the strand burning tests, a 2.95-kg 
(6y2-lb) batch of the 0.229-cm/s (0.090 in./s) modified propellant system 
was loaded into a 12.7-cm (5-in.)-diameter motor. The motor was fired 
at an average absolute pressure of 62.7 N/cm^ (91 psi), resulting in an 
average burning rate of 0.259 cm/s (0.102 in./s). The slightly higher rate 
was obtained by a reduction of the oxamide concentration to 1%. 

Combustion rate studies performed by Rocketdyne, a Division of North 
American Rockwell Corporation, indicated the burning rate of JPL 540 
at absolute pressure 68.9 N/cm- (100 psi) could be reduced from 0.356 
to 0.196 cm/s (0.14 to 0.077 in./s) by replacing 10% of the oxidizer with 
nitroquanidine, in addition to the other modifications. No adverse effects 
in processing or mechanical properties were noted in the propellant; 
however, in firing the 5.08-cm (2-in.)-diameter motor configurations, a 
reduction in predicted specific impulse resulted. 

Differential scanning calorimeter studies showed a dependence of 
burning rate on the iron concentration of uncured propellants. Based on 
this information and the effect of iron on SHTPB formulations, the effort 
was directed toward complete removal of iron from the propellant. If a 
minimum burning rate could be established in an iron-free environment, 
then iron could be quantitatively added to provide any desired rate. The 
cure catalyst used in 31 experimental batches of JPL 540 was FeAA. 
Other organo-metallic compounds were tested as replacements for this 
compound, but none would effect a complete propellant cure. Two metal 
chelates containing lead and titanium gave excellent cures in gum stock 
studies, but when combined into a propellant with oxidizer, they would 
not produce the same degree of cure. The synergistic effects of ammo- 
nium perchlorate oxidizer and cure catalyst, trace metals, or other com- 
ponents in the binder are little understood. Some ammonium perchlorate 
solubility in polypropylene glycol with dissociation is believed to take 
place as evidenced by the inactivation of metallic catalysts. Bonding 



31 



agents, such as the tertiary amines, MT-4, and dihydroxy propyl cyano- 
ethyl amine (C-1), apparently reduced this effect. Oxamide, in low con- 
centrations, was found to reduce the required concentration of the iron 
cure accelerator and may be functioning in the same manner. 

To obtain information on the combined effects of ammonium perchlo- 
rate on the binder polymerization process and the burning rate altera- 
tions, propellant batches were made with more chemically basic binder 
insoluble additives, such as calcium oxide (CaO), magnesium oxide 
(MgO), and disodium phosphate (NaHPOi). Calcium oxide, the more 
basic of the additives, prevented binder cure entirely, even in the pres- 
ence of the FeAA cure catalyst. Magnesium oxide produced a soft cure 
with increased burning rates. Disodium phosphate allowed a cure but 
increased the burning rate and reduced the mechanical properties. An- 
other binder insoluble material investigated, sodium fluoborate (NaBF4), 
produced acceptable cures with decreased burning rates but also de- 
graded the propellant strain capabilities. Of the insoluble materials 
examined, oxamide was the only one that did not alter the cure capability 
or degrade the mechanical properties while effectively contributing to 
reducing the burning rate. Of the soluble unreactive binder additives, 
only the IDDP material was evaluated, based on previous results in the 
polyether-polyurethane system. Due to the very low viscosity of IDDP, 
a thinner mix was produced which suggests the possibility of increasing 
the propellant total solids content. 

Another method investigated to reduce the burning rate of the poly- 
ether binder system was to change the binder polymer structure. Major 
changes in the binder formulation were not attempted since little change 
from the low-modulus, high-elongation mechanical properties of JPL 540 
could be tolerated. Since the molecular weight and functionality of the 
polyether monomer were fixed, the only available degree of freedom to 
investigate was the co-reacting low molecular weight polyols containing 
known flame suppressant functional atoms or groups. 

It was also desired to raise the melting point, or thermoplastic point, 
of the polymer to increase the temperature required for combustion. 
Among the reactive materials investigated were brominated polyols, 
phosphated polyols, halogenated phosphated polyols, and hydroxy- 

terminated amines. 

Burning rates were slightly reduced with the phosphated polyols; 
however, an unexpected rate increase was noted with a brominated 
polyol. The amines showed little or no influence in the low-pressure 
region (absolute) of 34.47 to 172.35 N/cm- (50 to 250 psi). A linear 
aliphatic diisocyanate (DDI) was compared with the aromatic toluene 
diisocyanate (TDI) as a chain extender, but no improvements were de- 
tected in either the strain capability or burn-rate reduction. 



32 



Unsaturated Hydroxy-Terminated Polybutadiene System 

The third propellant system investigated was an experimental propellant 
containing a UHTPB binder. This system is an attractive low-acceleration 
propellant candidate due to its inherent low burning rate characteristics. 
Also, it has a high solids loading capability and potentially can be cured 
at or near room temperatures. 

An exploratory series of fifteen 3785.4-cm'' (1-gal) batches of propellant 
were made with UHTPB. Although the results of the first series did not 
produce a high strain capability, low burning rates at absolute pressure 
68.9 N/cm- (100 psi) were achieved. Initially, a tin cure accelerator was 
used but reaction rates were so rapid that polymerization occurred during 
the mix cycle. Complete elimination of the cure accelerator did not suffi- 
ciently reduce the reaction rate to allow casting. Inclusion of the anti- 
oxidant phenyl beta naphthyl amine (PBNA) at 1% by weight of UHTPB 
helped reduce the reaction rate. The addition of 2% by weight of diethanol 
amine stearate further reduced the reaction rate and also helped to inter- 
nally plasticize the mix. However, larger quantities of the stearate tended 
to cause gellation, probably due to the amine reaction. A very good poly- 
merization was obtained when DDI was substituted for TDI as the chain 
extender. Batches made using a plasticizer, dioctyl adipate (DOA) at 20 
to 25% by weight of the binder, produced very fluid mixes which were 
easily processed at 86% solids loading. Burning rates for UHTPB formu- 
lations containing 82% solids were found to be 0.18 to 0.213 cm/s (0.071 
to 0.084 in./s) at absolute pressure 68.9 N/cm^ (100 psi). These rates 
were accomplished by using 340-^m ammonium perchlorate, a phos- 
phated polyol, iron-free aluminum, and IDDP. One formulation contain- 
ing a low molecular weight polyol, bis-hydroxy propyl aniline (Isonol 
C-100), gave a burning rate of 0.165 cm/s (0.065 in./s) at absolute pres- 
sure 68.9 N/cm- (100 psi) and a maximum stress of 186.2 N/cm- (270 psi) 
with a strain of 27% as determined from tensile specimens. Use of the 
ammonium perchlorate bonding agent MT-4 did not improve the strain 
capability of this propellant. Several hydroxy-terminated materials were 
co-reacted with the UHTPB in an effort to improve the strain capability 
but with little success. Straight UHTPB without reactive modifiers pro- 
duced propellants with 5-7% strain capabilities and burning rates of 
0.198 to 0.218 cm/s (0.078 to 0.086 in./s) at absolute pressure 68.9 N/cm= 
(100 psi). Use of stearates in the formulations increased the strain level 
to 17% without affecting the burning rate. 

Conclusions 

The most significant reduction in propellant burning rates was obtained 
by increasing the average particle size of the oxidizer. This was generally 
true for each binder system studied. Additional reductions in burning 
rates were obtained by incorporating binder soluble organo-phosphates 
and the binder insoluble oxamide. These modifications were made more 



33 



effective by the reduction in overall iron content of the propellant sys- 
tems. Preliminary studies with the unsaturated hydroxy-terminated poly- 
butadiene system showed promise as a low burning rate, advanced 

urethane-type binder. 

It was demonstrated that low burning rate propellant systems could 
be developed without seriously degrading the standard physical prop- 
erty characteristics. 



34 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Low Acceleratiori Rate Ignition for Spacecraft 

J. I. Shafer, L D. Strand, and F. A. Robertson 
Propulsion Division 



A g-dot ignition system for solid-propellant motors has been designed to 
prevent damage to fragile sensors or structural members on a spacecraft by 
producing, from a starting transient for the spacecraft of 0.3 g, a controlled 
buildup in thrust, such as to give an acceleration rate of about 0.3 g/s. 
The system consists of a 3-s, regressive-burning, controlled-flow igniter 
and a highly inhibited progressive-burning charge in the main motor. The 
igniter must operate in a hard vacuum and sustain burning of the unin- 
hibited portion of the propellant below its normal L* combustion limit 
through mass addition and heat transfer until the propellant surface has 
increased sufficiently to provide a stable motor chamber pressure. A specific 
internal torus-shaped igniter is described along with its advantages and 
disadvantages as well as potential methods of initiating burning in the 
hard vacuum with Pyrofuze. 



Introduction 

Current work on low-thrust, long-burning solid-propellant motor tech- 
nology is oriented primarily toward orbit insertion missions at Jupiter, 
Saturn, and perhaps Mercury, because of extensive scientific interest 
and a recent JPL study (unpublished) of outer-planet orbiter missions. 
Figure 1 shows an artist's rendering of a Jupiter orbiter spacecraft from 
that study. 

Note the long, highly flexible appendages for the scientific instruments 
and for the radioisotope thermoelectric generator on the opposite side 
of the spacecraft. These dictate a maximum spacecraft acceleration ten- 
tatively set at 1 g until trade-off studies can be made, and imply, inher- 
ently, low thrusts and long-burning times for outer-planet orbit insertion 
motors. Of special concern to the effort under discussion, the flexible 
appendages also dictate low acceleration rates, or g-dots, during the 
starting and shut-down thrust transients if limit cycling of the guidance 
components is to be avoided. 



35 



Figure 1. Jupiter orbiter spacecraft 

A low spacecraft acceleration rate during thrust initiation will be 
achieved through the use of an unconventional g-dot ignition system that 
will gradually build up thrust at a controlled rate of about 0.2 to 0.3 g/s 
from its starting value, about one-third to one-fifth the maximum accel- 
eration level. Reference 1 discusses some g-dot ignition feasibility studies 
and tests. 

The low spacecraft deceleration rate of 0.2 to 0.3 g/s during thrust 
decay would be provided through a propellant charge geometry that 
automatically produces a gradual thrust tailoff, i.e., through propellant 

sliver formation. 

Operation of the g-Dot Ignition System 

Figure 2 shows an artist's rendering of the 363-kg (800-lb)^ demonstra- 
tion motor, designated D-2, in which the torus-shaped g-dot igniter will 

be used. 

Operation of the igniter system can best be explained by reference to 
Figure 3, where the motor D-2 is shown in cross section with the torus- 
shaped g-dot igniter mounted on the submerged portion of the nozzle. 
The igniter is actually a small solid-propellant motor which bums with 



iWhere applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents 
the measured unit. 



36 







Figure 2. Demonstration motor D-2 



37 



MAIN MOTOR D-2 



g-DOT IGNITER 






SECTION A-A A-vJ 




3UU 




- 


200 


^■^^.^^^ y — IGNITER P 


- 




MOTOR P -^ ^^.^ 


- 


100 


/_„^ ''' "^ ^ — MOTOR WITHOUT 


„ 





r""^ ^■'^ IGNITER 

1 1 1 





400 



300 



1.0 2.0 

BURN TIME, s 



3.0 



Figure 3. The g-dot ignition concept 

supersonic exhaust for about 1% s of its 2%-s burning time. Its combus- 
tion gases pass radially outward from numerous nozzles, impinging on 
the dish-shaped propellant surface. Igniter pressure (absolute) decreases 
from about 241 N/cm- (350 psi) to about 124 N/cm^ (180 psi). 

The main motor propellant surface is highly inhibited, as shown in 
section A-A, Figure 3, with an inhibiter pattern such as to produce a 
highly progressive burning surface as the propellant regresses under the 
inhibitor surface. Thus, if the motor propellant could burn at a very low 
pressure by itself, its pressure-time curve would resemble the broken 
line in Figure 3— with an initial pressure (absolute) of only 3.45 to 
6.89 N/cm- (5 to 10 psi). 

In reality, because of the L* combustion limit of about 44.8 N/cm- 
(65 psi) absolute, the motor would not bum by itself below that pressure. 
However, v/hen hot exhaust gases from the independent controUed-flow 
igniter are injected into the main motor, the mass addition raises the motor 
pressure (absolute) to about 34.5 to 37.9 N/cm^ (50 to 55 psi) and burn- 
ing of the main charge is sustained below the motor L* limit by the heat 
transfer and mass addition. The resultant low pressure and thrust level 
permit the spacecraft to meet its 0.3-g initial acceleration requirement. 

The main propellant burning surface and, consequently, chamber 
pressure increase with time in a controlled manner until the motor is able 
to sustain combustion without mass addition from the igniter. The small, 
thin inhibiter strips are partially, or completely, consumed before being 

ejected out of the nozzle. 



38 



The pressure-time relationships shown in Figure 3 represent nominal 
performance values. In practice, however, operation of the main motor 
below its normal L* combustion limit has produced low-frequency low- 
amplitude oscillations characteristic of L* combustion instability near the 
extinction pressure (Reference 1). 

Concern about potentially unacceptable acceleration rates from these 
oscillations prompted a recent series of computer runs in which the effect 
of the oscillations on the spacecraft attitude controls was simulated using 
the Thermoelectric Outer-Planet Spacecraft model, modified to include the 
retro-propulsion for a Jupiter orbiter mission. It was concluded that, for 
both rigid and flexible body dynamics, the oscillations arising from the 
use of the g-dot igniter and other low-amplitude bumps and spikes 
which may occur in the thrust profile had no apparent effect on the 
attitude control system. 

In the same series of computer runs, the effect of initial acceleration 
during igniter initiation and the acceleration rate during igniter burning 
on the spacecraft controls was also evaluated. The following results 
were obtained: 



Maximum initial , . . . Effect on spacecraft 

acceleration, g i . , controls 

bummg, g/s 

0.2 0.2 Acceptable 

0.4 0.4 Acceptable 

0.6 0.6 Limit cycling 

Because tests were not all-encompassing in their scope, conservative 
values of 0.3-g maximum acceleration and 0.3-g/s acceleration rate were 
adopted as design criteria for the ignition system and motor thrust decay. 
When the actual spacecraft configuration is known better, these design 
values should be reassessed. 

Another significant deviation from the nominal performance values of 
Figure 3 stems from the ignition delay in initiating burning of the 71.1-cm 
(28-in.)-diameter main motor by the g-dot igniter (typically 0.2 to 0.3 s 
in small-motor g-dot firings). Figure 4 shows the igniter pressure-time 
curve, and the results of the calculations for main motor pressure- 
time curves when ignition delays were assumed to be 0, 0.3, and 0.6 s. 
Results were obtained from an overall mass flow balance for the motor. 

The ratio of the mass flow rate of the igniter to that of the main 
motor, a critical parameter in sustaining burning below the L* combus- 
tion limit, is given in Figure 4 to show that its value lies above the 



39 



o 
o 



2.5 



RATIO 



0NO TIME DELAY 
(D0.3-S DELAY 
@0.6-s DELAY 



-SUBSONIC FLOW BEGINS 
FOR IGNITER 




MAIN MOTOR P 
c 

-I 



500 



400 



300 



200 



100 



300 



200 xf 



- 100 



s 

< 

X 

u 



2.0 
BURN TIME, s 



4.0 



Figure 4. Mass flow rate ratio and cliamber pressure vs burn time for 
main motor time defays of 0, 0.3, and 0.6 s 



desired value of approximately one at the start of main motor burning 
for the given motor and igniter design conditions. Accelerations and 
acceleration rates fall within the 0.3 allowable values. Thus, it is believed 
that normal ignition delays will cause no difficulties in the firing of the 
demonstration motor D-2. 



Internal Versus External Igniter System 

There are advantages and disadvantages to an internal (torus) igniter 
compared to a 2- to 3-motor external igniter system, the more conven- 
tional arrangement. Figure 5 shows the two design concepts. The inter- 
nal igniter was finally adopted, based on the following judgments. 

The internal torus has the disadvantage that the main motor nozzle 
could become partially or completely plugged (disastrously) if uncon- 
trolled breakup of the empty igniter case occurred during main motor 
burning. The problem appears to have been solved (1) by blocking the 
igniter into a cradle and cementing it to the nozzle phenolic insulation, 
and (2) through the use of a thermoplastic igniter case that will melt into 
a viscous glob around the nozzle and tend to wash away gradually 
into the stream of hot gases. 

A second disadvantage results from the interface with the safe and 
arm mechanism, which, according to launch operations specifications, 
must be located outside the main motor. The safe and arm mechanism 
is relatively simple for external igniters where it could be located at the 
head end of the units with the initiator squibs. The use of Pyrofuze is 
being considered for the torus internal igniter in an effort to reduce the 
problem— or perhaps eliminate it. 



40 



EXTERNAL IGNITER 
(ONE OF TWO OR 
THREE) 



MOTOR CHAMBER - 



CHAMBER 
INSULATION 




NOZZLE 
INSULATION 



MAIN MOTOR 
NOZZLE 



Figure 5. Internal (torus) igniter vs external igniter 

Advantages of the internal igniter include (1) a required igniter hard- 
ware life of only 3 to 5 s compared to 140 s for the external igniters; 
(2) lower weight, fewer igniters and safe and arm mechanisms than the 
external system [the thickness of the insulation would be 1.02 cm 
(0.40 in.) in the external motor compared with 0.076 cm (0.03 in.) in the 
torus]; (3) flame spreading with 12 nozzles over the 71.1-cm (28-in.)- 
diameter charge surface should be better; and (4) the main motor case 
design and fabrication would be easier— no bosses on heat-treated cham- 
bers, no ports through the insulation and propellant, and fewer igniters 
to load with propellant. 

Design of the g-Dot Igniter 

Design features of the g-dot igniter are shown in Figure 6. Its outer 
diameter will be 28.7 cm (11.3 in.) and the small tube diameter will be 
about 5.33 cm (2.1 in.), with a wall thickness ranging from 0.3175 to 
0.635 cm (Vs to % in.). The igniter case will be made of polycarbonate, 
a thermoplastic material, and will have 12 graphite nozzles equally 
spaced around the case and firing radially outward to promote flame 
spreading over the main propellant charge. Each nozzle will have a 
throat diameter of only 0.584 cm (0.23 in.); a propellant with only 2% 
aluminum has been selected in order to minimize changes in throat area 
and pressure from oxide deposition. The propellant weight is estimated 
at 1.07 kg (2.35 lb); the inert weight is the same. A layer of 0.076-cm 
(0.030-in.) rubber insulation on the inside, and perhaps on the outside, 
helps protect the plastic case for its 2y2-s burning time. It has been 
designed with a safety factor of 2, based on limit loads. 



41 




Figure 6. The g-dot igniter 



Initiating Igniter Burning 

The question of how best to initiate burning in the g-dot igniter in a 
hard vacuum is unanswered at this time. Vacuum ignition systems are 
available but an operationally simple system for a torus igniter poses 

something of a challenge. 

Ignition, itself, involves the addition of external heat to the propellant 
at a rate such that its own subsequent decomposition and combustion 
produce sufficient heat to sustain further decomposition and burning 
when the external heat source is withdrawn. The process is complicated, 
especially in a vacuum, by (1) the propellant deflagration limit Pm, that 
absolute pressure below which the propellant will not bum [about 2.07 
to 2.76 N/cm^ (3 to 4 psi) for the propellant under consideration]; 
(2) short residence times for the igniter combustion gases, i.e., low L* 
motor values, so that there is insufficient time for heat transfer to the 
propellant to develop the required thermal gradient beneath the propel- 
lant surface, a necessary condition for sustaining burning; and (3) rapid 
decreases in pressure, i.e., high dp/dt, that can quench the burning— the 
rapid decrease may stem from the blowout of partial obstructions to gas 
flow or nozzle closures deliberately introduced earlier to raise the local 
pressure at the ignition surface above the Pn value at which burning 
can be sustained. 

The use of Pyrofuze wire is being considered for initiating burning in 
the igniter while in a hard vacuum. The Lockheed Propulsion Company 
and the Air Force Rocket Propulsion Laboratory have used Pyrofuze 



42 



successfully for igniting motors (Reference 2) but their experience ap- 
pears to have been limited to firings at atmospheric pressure. 

Pyrofuze itself is a coaxial wire with an aluminum core surrounded 
by a tube of palladium in intimate contact with the core. It has the 
unique property, when heated electrically or chemically to the 933 K 
(1220°F) melting point of aluminum, of instantly generating a large 
exotherm, under gas pressure or in a vacuum, due to the resultant alloy- 
ing. Temperature in the wire alone can reach about 3030 K (5000 °F), 
well above the 477 to 700 K (400 to 800 °F) ignition temperature range 
of most solid propellants. 

Figure 7 shows the cross section of the torus tube and location of the 
Pyrofuze, which is used here as a special type of hot wire igniter. A 
continuous braid of 8-strand 0.076- to 0.25-mm (3- to 10-mil) wire, or 
0.025- to 0.127-mm (0.001- to 0.005-in.)-thick by 3.17-mm (0.125-in.)-wide 
Pyrofuze foil, would be buried just beneath the surface of the propellant 
slot. When current is passed through the wire, burning would be initiated 
throughout the charge circumference in the bottom of the slot so that 
hot combustion gases must pass over the walls of the propellant slot to 
reach the nozzle, thus promoting flame spreading and tending to raise 
the pressure locally near the line of ignition. 



-ALUMINUM 
FOIL CLOSURE 




PYROTECHNIC 
BOOSTER CHARGE 



Figure 7. Initiation of g-dot igniter with Pyrofuze 



43 



Ten of the 12 nozzles in the torus will have thin aluminum foil as 
nozzle closures to raise the igniter L* to 10.5 m (414 in.) for the two 
open nozzles and to increase the residence time of the hot gases in the 
igniter. To avoid abrupt drops in igniter pressure (high dp/dt) as the foil 
is ruptured, one nozzle will be closed with one layer of foil, three nozzles 
with two to three layers of foil, and six nozzles with three to five layers. 

If the high igniter L* and the nozzle closures fail to provide sustained 
burning from a hard vacuum start, the propellant will be (1) preheated 
locally by the Pyrofuze, below the propellant decomposition temperature 
of 450 to 477 K (350 to 400 °F), by means of a low current for 5 to 30 s, 
then (2) ignited by triggering the Pyrofuze exotherm with a substantially 
higher current. 

Finally, if all of the preceding approaches were to prove inadequate, 
a propellant that is more easily ignited than the polyether polyurethane 
JPL 540 Mod C will be substituted or, alternately, the use of a pyro- 
technic booster charge or paste (Figure 7) will be used in the slot to 
provide more heat in a longer duration operation. 

Processing and Igniter Testing 

Although formation of the propellant charge in the torus case would 
appear to be difficult, practice tests have already revealed acceptable 
techniques. With a split mandrel of Teflon machined to form the finished 
propellant contour taking the place of the outer ring of the torus (Fig- 
ure 7), propellant is vacuum-cast radially through the mandrel until a 
surplus fills the sprue. It is then cured for four days at 333 K (140°F), 
cooled, and the split mandrel removed. Before firing, the two sections 
of the torus are bonded together with an epoxy adhesive. 

The future testing program should include: a proof-pressure test of 
the case, a qualification static firing of the igniter alone in the open, and 
one or more firings in an ignition test motor that duplicate the ignition 
phase of the D-2 motor. If practical, a simulated altitude firing of the 
ignition test motor should precede the firing of the demonstration 
motor D-2. 

References 

1. Strand, L. D., "Low-Acceleration Solid Propellant Rocket Ignition 
Study," in Proceedings of the 26th JANNAF Meeting, Vol. I, July 14r- 
16, 1970. Chemical Propulsion Information Agency, Johns Hopkins 
University, Silver Spring, Md. (Confidential). 

2. Laufman, P. N., and Dilts, H. S., Exothermic Bimetallic Ignition 
System, AIAA Paper 69-425. AIAA 5th Propulsion Joint Specialist 
Conference, U. S. Air Force Academy, Colo., June 9-13, 1969. 



44 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Cyanate loo and the Uremic Syndrome 

J. D. Ingham 
Propulsion Division 



A critical survey is made of the literature that logically provides an 
hypothesis that relates the symptoms of kidney failure (uremic syndrome) 
to the presence of cyanate ion derived from metabolic urea. If the hy- 
pothesis can be unequivocally verified, the consequences will provide a 
solution to the problem of defining the primary toxic factor in uremia and 
should lead to substantial improvements in the available treatment for 
patients with kidney failure. 



Introduction 

The potential significance of cyanate ion with respect to the uremic 
syndrome was noted during some recent work on alternative methods of 
purification of uremic blood for application to treatment of kidney failure. 

Metabolites, or waste products, that are eliminated by normal kidney 
function include urea, uric acid, indican, phenols, guanidine bases, 
organic acids, magnesium, phosphate, potassium, sulfate, and excess 
water. Although urea is formed in the largest quantity and its concen- 
tration in uremic blood is monitored to determine the requirements and 
effectiveness of conventional hemodialysis, it is not considered partic- 
ularly toxic to persons with normal renal function. It is generally con- 
ceded that the toxic metabolites responsible for the pathological symp- 
toms of uremia have not yet been determined. Thus, this absence of 
fundamental knowledge of the chemical and physiological processes 
attending renal failure remains as the greatest limitation in providing 
adequate and more effective treatment for uremic patients (Reference 1). 

Discussion 

Paradoxically, there is ample evidence in the medical literature that 
cyanate ion formed from metabolic urea can cause symptoms charac- 
teristic of uremia. However, it has not been proven nor stated elsewhere 
that cyanate accumulation and consequent carbamylation of proteins or 



45 



other physiological cyanate reactions are primarily responsible for the 
deterioration of uremic patients. In fact, the vast majority of publica- 
tions on uremia or artificial kidney research do not mention cyanate at 
all, and there have been no published clinical methods developed to 
readily measure cyanate at expected physiological concentrations. 

In 1953, Merrill, et al. (Reference 2), presented results to prove that 
urea vi^as not the cause of uremic symptoms. They observed that patients 
improved clinically following hemodialysis even if their blood urea level 
did not decrease. Urea is sometimes given to patients as a diuretic or to 
relieve intercranial or intraocular pressure. In one hospital over 1300 
nonuremic patients have tolerated a daily dose of 0.001 to 0.002 kg of 
urea/kg body weight for short periods without any ill effects (Refer- 
ence 3). 

Furthermore, up to 0.008 kg of urea/kg body weight has been given 
daily to normal dogs intravenously for seven days without manifestation 
of toxicity (Reference 4). However, uremic dogs expired within a few 
days when a 0.5 to 3 wt % aqueous urea solution was added to their peri- 
toneal dialysis solution, while similar dogs dialyzed without added 
urea survived an average of 39 days (Reference 5). Gilboe and Javid 
(Reference 6) treated three groups of uremic dogs with normal peritoneal 
dialysis solution (Group I) and with dialysis solution containing 1 wt % 
aqueous urea solution (Group II) or 0.015 wt % potassium cyanate 
(Group III). Group I survived 14 ± 0.17^ days, whereas Groups II and 
III survived 7 ± 0.60 and 6 ± 0.53 days, respectively. The same uremic 
symptoms, i.e., weakness, refusal to eat, diarrhea, intestinal hemorrhag- 
ing, and decreasing body temperature, were observed for Groups II and 
III. Since the concentration of cyanate in the tissue fluid of the Group III 
dogs was estimated to be approximately the same as that expected to be 
produced from a 1% aqueous urea solution in 24 hours, it can be con- 
cluded that it is probably the cyanate formed from urea, and not urea, 
that is primarily responsible for uremic symptoms. Other work has shown 
that the pharmacological effects of large doses of cyanate on healthy rats 
and rabbits are caused by cyanate and not any substance into which it 
may conceivably be transformed in the body [urea, ammonia, cyanide, 
or thiocyanate (Reference 7)]. 

At 38 °C, about seven days are required to establish the equilibrium 
concentration of cyanate from urea, which is about 0.5% of the initial 
urea concentration (17), up to (U) ^ 1 molar (Reference 8). 

Therefore, nonuremics would not be expected to develop uremic 
symptoms from relatively large doses of urea because the urea and any 



1 Standard error. 



46 



urea products would be removed by normal kidney function before 
toxic amounts of cyanate would form. 

It has been definitively established that cyanate reacts rapidly with 
sulfhydryl and amino groups of proteins and inhibits ribonuclease enzy- 
matic activity in vitro (References 9 and 10). In fact, cyanate carbamyla- 
tion and decarbamylation of functional groups have been used as a 
protecting reaction in the synthesis and study of biological compounds. 
Thus, it appears that the physiological activity of cyanate ion probably 
results from carbamylation of free sulfhydryl and amino groups in pro- 
teins or amino acids. 



Summary and Conclusions 

(1) In aqueous solutions of urea small equilibrium concentrations of 
cyanate are formed: 

O 

NH^— C— NHs t^ NH: + CNO- (I) 

(2) In uremic patients cyanate ion is probably formed by Reaction I 
over a period of days, from the initial metabolic urea. 

(3) Urea is not toxic to normal subjects, but 1% urea or 0.15% 
potassium cyanate added to the peritoneal dialysate of uremic dogs 
greatly accelerates the onset of uremic symptoms and death. 

(4) It appears likely that uremic symptoms result from reaction of 
cyanate ion with sulfhydryl and amino groups in body proteins and 
amino acids: 

O 

II 
RS- -1- HNCO + HOH ±;RS — C — NH, + OH" (II) 

No further work has been done to clarify or define the role of cyanate 
ion in uremia. 

One suggested reason for the apparent neglect in this area is the un- 
availability of a direct method for cyanate analysis at expected physio- 
logical concentrations. Therefore, Dr. J. D. Arterberry- is actively 
engaged in research on a new method of analysis for cyanate in blood 
and urine. Preliminary results with this method indicate the presence 
of expected concentrations of cyanate in normal urine samples. When 
the reliability of the method has been unequivocally established, uremic 
and normal blood will be analyzed for cyanate. Further, since Reaction 



2USC School of Medicine and Chief of Staff, Central Receiving Hospital; also col- 
laborator and consultant to JPL on the Laboratory's Purification of Uremic Blood 
task. 



47 



II is readily reversed at alkaline pH, the blood proteins of uremics can 
be decarbamylated to form cyanate to determine the extent of reaction 
of physiological cyanate compared with normal blood. If it is found that 
uremic proteins are partially carbamylated, the implications of State- 
ment 4, above, will have been substantively verified. Experiments will 
then be carried out to determine methods of inhibition of carbamylation 
in uremic patients. If the role of cyanate ion in uremia is as significant 
as suggested here, the expected consequences of a continuation of this 
effort may be: (1) an elucidation of the primary causes of the uremic 
syndrome, and (2) much more efficient and acceptable methods of treat- 
ment of uremic patients. 

Although any modifications of clinical treatment would be extremely 
presumptive until the proposed investigations are completed, the modi- 
fications might eventually involve occasional hemodialysis to remove 
excessive urea and other metabolites, and frequent oral or intravenous 
administration of relatively small amounts of nontoxic sulfhydryl com- 
pounds or other drugs. The latter would be developed to remove cyanate 
as it is formed, or to promote decarbamylation by shifting the equi- 
librium in Reaction II to the left. 



References 

1. Proceedings of the Second Annual Contractor's Conference of the 
Artificial Kidney Program, National Institute of Arthritis and Meta- 
bolic Diseases, Bethesda, Md., Jan. 22-24, 1969. 

Merrill, J. P., Legrain, M., and Hoigne, R., Am. J. Med., Vol. 14, 

p. 519, 1953. 



7, 

8 

9 

10, 



Javid, M. J., Swfg. Clin. N. Am., Vol. 38, p. 907, 1958. 

Garvin, P. S., Jennings, R. B., and Gesler, R. M., Pharmocologist, 

Vol. 1, p. 71, 1959. 

Grollman, E. F., and Grollman, A., /. Clin. Invest, Vol. 38, p. 749, 

1959. 

Gilboe, D. D., and Javid, M. J., Proc. Soc. Exp. Biol. Med., Vol. 115, 

p. 633, 1964. 

Birch, K. M., and Schutz, F., Brit. }. Pharmaco., Vol. 1, p. 186, 1946. 
Dirnhuber, P., and Schutz, F., Biochem. J., Vol. 42, p. 628, 1948. 
Stark, G. R., /. Biol. Chem., Vol. 239, p. 1411, 1964. 

Stark, G. R., Stein, W. H., and Moore, S., /. Biol. Chem., Vol. 235, 

p. 3177, 1960. 



48 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Oil-Absorbing Polymers 

H. E. Marsh, Jr. 

Propulsion Division 

A new research program has been started to develop technology needed 
to make practical use of a well-known characteristic of elastomeric cross- 
linked polymers. Such polymers, of which class modern solid-propellant 
binders are members, absorb large amounts of compatible solvents, and yet 
remain solid. Two goals are being considered in this program. One goal is 
a material that can be used as a dietary additive which will selectively 
absorb fats and oils in the digestive tract and hold them until elimination, 
thus preventing their assimilation. The other goal is a material that can be 
used in oil-slick mop-up operations. This article presents the interim results 
on the formulation and testing of three polymer types. Performances 
amounting to oleic acid absorption of up to 20 times the dry polymer 
weight have been measured. Higher values are expected. Both mineral oil 
and a cooking oil are also absorbed, but to a smaller extent. 



Introduction 

The chief distinguishing structural feature of the class of polymers 
known as thermosetting is that the component polymeric molecules are 
tied together in a three-dimensional network. The average length of 
polymer chain between cross-hnking (interconnecting) sites, together with 
the flexibility /stiffness character of the chain material, determines the 
mechanical properties of the polymer. Regardless of chain flexibility, 
highly cross-linked polymers are rigid. On the other hand, polymers with 
long chains between cross-links are rubbery, providing those chains are 
flexible. Another characteristic of the latter type of polymer that has been 
known and studied for a long time is its ability to absorb extremely large 
quantities of compatible solvent and yet remain solid. 

A new research program has been undertaken to take practical advan- 
tage of the high absorption capacity of suitably prepared network poly- 
mers. Two goals are being considered. One goal is the development of 
polymers with a high affinity for the fats and oils common in foods that, 
being otherwise harmless, could be used as a dietary additive for the 
control of fat assimilation. Being inert, the polymer would pass through 



49 



the digestive tract absorbing and retaining fats and oils, including cho- 
lesterol, for elimination. The other goal is the development of similar 
materials that will be useful in oil-slick mop-up procedures. 



Approach 

The technology adopted to make high capacity absorbing cross-linked 
polymers is based on knowledge gained in work with solid-propellant 
binders (References 1 and 2). The aim is to make polymers that are cross- 
linked, so that they will remain solid even though swelled by large 
quantities of absorbed oil, but at the same time provide an average chain 
length between the cross-link sites as large as possible to obtain maxi- 
mum capacity. 

Preparation 

There are two steps in the process: synthesis and extraction. The syn- 
thesis step consists of mixing together appropriate quantities of several 
polyfunctional ingredients, along with a polymerization catalyst, and 
causing them to polymerize by means of heat. Network pol)Tner theory 
is used to calculate the ratios of ingredients that should yield polymers 
with the desired characteristics. The ideal composition is near the incip- 
ient gelation boundary (Reference 1). However, in practice, this calcula- 
tion serves only as a starting point for an empirical search. The necessity 
for empirical experimentation is caused by the fact that polymer formu- 
lations with the best absorption capacities are so lightly cross-linked 
that they are almost liquids instead of solids. Factors not accounted for 
in the theoretical calculation, such as incomplete reaction, non-ideal 
functionality distribution of the components, and side reactions, all inter- 
act with the sensitivity of such formulations to cause an unpredictable 
shift of the real solid/liquid boundary from the theoretical one. Thus, in 
the empirical search for a good formulation, a series of samples are 
made at the same time with composition ratios varying over a range 
estimated to bound the problem. A satisfactory series will yield some 
liquid and some gelled polymers. Often, one or more additional sets must 
be run, either to find the correct range or to refine the desired point. 

Gross distinction between liquid samples and solid ones is made by 
visual observation of the flow properties of the polymer. However, 
some samples that appear to be solid turn out later to be only high 
molecular-weight Hquids. This is evidenced by total extraction in the 

next process step. 

Another characteristic of the desired lightly cross-linked polymer (in 
practice, but not necessarily in theory) is that it consists of two sepa- 
ratable fractions. The desired fraction is the lightly cross-linked gel, or 
solid. In homogeneous solution with the gel is the sol, or liquid fraction. 



50 



The latter is a polymerized material that did not reach the size and 
complexity necessary for it to become part of the gel. Repetitive solvent 
extraction of a fresh polymer removes the sol fraction, leaving a residue 
of "dry" gel. Soxhlet extraction is used in the present work to carry out 
this operation automatically. 

Screening and Evaluation 

The criterion for a good polymer is its capacity to absorb a large 
amount of oil (of a type critical to the objectives of the program). 
Although the main stress in the program is in the absorption of biologi- 
cally important oils and fats, a laboratory grade of mineral oil is used 
as one of the test materials, as a model for the oil-slick problem. In 
private communication. Dr. David Blankenhorn of the USC School of 
Medicine recommended the following compounds for testing the feasi- 
bility of the fat assimilation control concept: 

(1) Carboxylic acids: palmitic acid, oleic acid, myristic acid, butyric 
acid, and a C-22 acid. 

(2) Alcohols: cholesterol. 

(3) Esters: triglycerides of palmitic and oleic acids, and the palmitate 
of cholesterol. 

Since it would be very inefficient and expensive to test each new 
polymer with all of these materials, the oleic acid was the only one 
selected for the screening tests because it is the least expensive and is a 
liquid at room temperature. The other compounds will be used in the 
evaluation of polymers selected in the screening tests. 

Because of experimental difficulties, the accuracy of the measurement 
of the absorption capacity is limited. The current procedure starts with 
the immersion of a weighed quantity of polymer in a volume of the test 
liquid. It is examined daily, and when the polymer appears to have 
stopped swelling, it is removed and drained (most of the surface liquid 
is removed by blotting with tissue). The last operation is where the 
uncertainty lies, because of the lack of uniformity of surface configura- 
tion from sample to sample, and also because the structural weakness of 
some swollen gel samples gives difficulty in carrying out the operation. 
Lack of accuracy in these measurements is not critical in the screening 
tests, however. As will appear in the results below, the differences in 
capacity are large in comparison to such errors in measurement. 

Polymer Types Investigated 

For all of the past work, and for as long as it continues to be practical, 
the urethane reaction is the adopted means of curing. Since this is the 
chief cure system used in the fabrication of JPL propellants, a wide 
variety of potentially useful materials are readily available. 



51 



An anticipated major factor in the absorption capacity of network 
polymers is the chemical nature of the chain-forming ingredient. In 
advance of experimentation, hydrocarbon chains were expected to have 
a greater affinity for the oils in question because of the long-chain 
hydrocarbon characteristic common to them. Several hydrocarbon pre- 
polymers are being tested: some unsaturated (polybutadiene), and some 
saturated (similar to ethylene-propylene copolymers). A common poly- 
ether (polypropylene oxide) is also being tested, primarily because it is 
not hydrocarbon. Polyesters are under consideration; however, their 
stability in the digestive system may be in question. 



interim Results 

Formulation Studies/Screening Tests 

Three polymer systems have been investigated: unsaturated hydro- 
carbon, mixed saturated/unsaturated hydrocarbon, and polyether. Reas- 
onably good absorption of oleic acid has been obtained with each system. 
The highest absorption capacities measured so far for the above three 
systems were, respectively, 1390, 1210, and 2050% oleic acid absorbed, 
based on the dry weight of the polymer. 

In many cases, the formulation series sets did not correlate closely 
with theory. This was expected because no effort was made to control 
reaction conditions carefully for this purpose. The desired practical 
results were achieved, however. An example of a formulation series in 
search of a good absorber is given in Table 1, This set of samples was 
a series of unsaturated hydrocarbon formulations in which all factors 
except the hydroxyl-to-isocyanate ratio R were held constant. According 
to theory, the gel point R for this set should be 1.25. Two samples were 
unable to produce a gel because R was too high. The variation in sol/gel 
ratio and absorption capacity of the two soHd products are in the ex- 
pected directions. If this particular system were to be selected for 
further work, another series would be run in which a number of R values 
between 1.32 and 1.52 would be tried. A formulation having maximum 
absorption capacity should be found in that range. 

Table 1. Effect of formulation parameters on absorption capacity 

„ , Hydroxyl-to- „ , , , , 

S^f^ isocyanate Product ^"^/^el Oleic acid 

number .. ratio absorbed, % 



101 


1.16 


Solid 


0.35 


830 


102 


1.32 


SoM 


0.69 


1380 


103 


1.52 


Liquid 


- 


- 


104 


1.79 


Liquid 


- 


- 



52 



Testing Oils and Solvent Polymerization 

In most of the past work, only oleic acid was used in absorption 
screening tests. To broaden the screening tests, it was decided to try, 
as an inexpensive model for the ester-type oils, a commercial cooking 
oil. Cooking oils are refined natural mixtures of triglycerides from vege- 
table sources. Wesson oil was chosen. It was also decided to include 
mineral oil as a model for strictly hydrocarbon materials. It is important 
to mention in this regard that mineral oil was used in the first exploratory 
tests. An absorption capacity of over 800% was attained then, using an 
unsaturated hydrocarbon polymer. 

First tests with the Wesson and mineral oils were made with polyether 
polymers. The results indicated that the polymers' capacities for these 
two oils were between about one-fiftieth and one-fifteenth of their 
previously measured capacities of oleic acid. These results are prelimi- 
nary; however, if they are representative, they show that the unreacted 
carboxyl on the oleic acid molecule contributes largely to its solubility 
in polyether poljTtners. 

The test was repeated with two unsaturated hydrocarbon polymer 
samples that had been in storage for many weeks. Theoretically, these 
oils and hydrocarbon polymer should be compatible. The results were 
about the same as with the polyether polymers; however, the capacity was 
much lower than the 800% found previously with a hydrocarbon 
polymer. 

Two possible explanations are proposed for this undesirable result. The 
first is that the unsaturated hydrocarbon poljoners stored for some time 
in air may have undergone oxidative cross-linking, similar to the process 
which hardens paints and varnishes. 

The second explanation is that the recently tested polymers were 
made in bulk, whereas the earlier, more successful polymer had been 
made in 50% xylene. Network polymers made in solution would be 
more extended (would have fewer chain entanglements) and as a result 
might be more extensible even after drying. Two fresh sets of hydro- 
carbon polymers were made in solution; one polymer was unsaturated 
and the other was mixed saturated/unsaturated. Absorption tests have 
not run their full time yet, but absorption capacity for mineral oil has 
improved by a factor of about IVz, and even higher for Wesson oil. 

Polymer Reinforcement 

The mechanical weakness of some swollen gels has caused difficulty 
in handling during testing. Mainly for the purpose of expediting screen- 
ing tests, the formation of polymers on reinforcing substrates was 
investigated. A secondary aim was to demonstrate that greater strength 



53 



could be provided, when needed in application. A good substrate must 
reinforce the polymer during absorption without restricting the absorp- 
tion capacity appreciably. 

The substrate materials tried were cotton fibers, pulled from cosmetic 
cotton batting, nylon tow, and fine-mesh nylon screen. The very high 
surface area of these materials proved troublesome in two respects. 
Formulations with as high as 3 to 5% of loose fibers appeared to be 
too highly loaded for useful processing. Interference with curing, 
probably caused by undesirable chemical activity at the surface, was 
also encountered. Substrate loadings in the range of 0.5% were found 
to be more suitable with respect to both problems. 

Substrate testing is not completed. However, for testing purposes, the 
nylon screen with a thin film of polymer appears to be a practical 
arrangement. One such sample exhibited an absorption capacity of 
1460%. To curtail the impairment of curing, it is planned to pretreat the 
screen with tolylene diisocyanate, the curing agent. 



Time-Consuming Operations 

Another factor, besides the lack of reproducibility in removal of surface 
oil in absorption tests, which has contributed to uncertainty in the data, 
is the length of time required for complete absorption. Although the 
required time has not been determined, it appears to be of the order of 
two weeks. The extraction operation also is slow; it takes five days. 

Recent tests have shown that moderate temperature elevation increases 
the rate of absorption considerably. Heretofore, testing has been done at 
room temperature, which has been ranging from 17 °C (62 °F)^ to 24 °C 
(75 °F). A study is currently being carried out at two temperatures: 38 °C 
(100°F) and 49°C (120°F). Preliminary data indicate that absorption 
values obtained previously in one to two weeks at room temperature 
were achieved in two days at 49°C (120°F). 

The preparation of thin polymer samples on nylon screen substrates 
is expected to increase the rates of both extraction and absorption be- 
cause the reduction in, and better control of, diffusion distance. 

The elevation of temperature will also be investigated in the extrac- 
tion operation. This will be accomplished by the substitution of the 
higher boiling solvent xylene for benzene. 



^Where applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents 

the measured unit. 



54 



Questions of Polymer Stability 

Occasionally, samples which have undergone extraction, yielding a 
solid product, seemed to have disappeared in the absorption test. This 
should not occur because a solid residue from extraction is positive 
evidence of a cross-linked polymer. The most likely explanation is a 
chemical displacement of previously reacted hydroxyl in the polymer by 
the carboxyl group on the oleic acid. Such a reaction vi'ould simul- 
taneously result in the introduction of an extra monofunctional com- 
ponent and a shift in the stoichiometric ratio, both of which would 
reduce the extent of cross-linking. 

An experiment was started to investigate the possibility of polymer 
size degradation by reaction of oleic acid into the polymer. The experi- 
ment was based on the often used principle of determining the molecular 
weight (or size) of dissolved polymers by viscosity measurement. One 
of the previously made polymer samples that had remained a liquid 
after cure was dissolved in a plasticizer, and oleic acid was added so 
that the final solution had 21% polymer and 12.5% oleic acid. The 
solution was stored at room temperature, and the viscosity was mea- 
sured once or twice a week, along with the temperature, in order to 
normalize viscosity and eliminate temperature as a parameter. After a 
period of a month, no change in the viscosity of the solution was de- 
tected. If a significant amount of the suspected reaction had occurred, 
the viscosity of the solution would have dropped because of the resulting 
decrease in molecular weight. 

As far as this experiment has gone, there is no evidence that oleic acid 
degrades the polymer. The question of disappearing gels is still open. 
However, there is an indication that one factor in the intended environ- 
ment will not cause degradation of urethane-cured polymers. 

Conclusions 

Preliminary results indicate that: 

(1) All three polymer types tested (unsaturated hydrocarbon, mixed 
saturated/unsaturated hydrocarbon, and polyether) have good 
absorption capacity for oleic acid. The highest capacities measured 
range from 12 to 20 times the dry weight of the absorbing polymer. 
None of these polymers have been optimized. 

(2) The absorption capacities for both mineral oil and Wesson oil by 
these polymers appear to be considerably less than for oleic acid. 

(3) Solution polymerization produces polymers that either have higher 
capacities or more rapid absorption rates than bulk polymerization 
does. 

(4) Carboxylic acids, as represented by oleic acid, do not appear to 
degrade the urethane-cured polymers investigated. 



55 



Future Work 

Future and continuing tasks in this program are listed as follows: 

(1) Formulating and processing studies of the three polymer types 
will be continued to produce optimum products. Technical im- 
provements, including substrate reinforcement and solvent poly- 
merization, will be used. Reproducibility of preferred formulations 
will be investigated. 

(2) The absorption capacities of the selected formulations of each 
polymer type for oleic acid. Wesson oil, and mineral oil will be 

measured. 

(3) Absorption of the other selected biologically important fats and 
oils will be studied. 

(4) The general technology of producing oil-absorbing polymers will 
be investigated. Modifications of the types of polymers under 
study, as well as new types, will be tried. 

(5) In consultation with medical experts, plans for future investiga- 
tion will be made. Subjects to be studied must include the mea- 
surement of the stability of high absorbing polymers in simulated 
environments, whether or not toxic effects can be discovered, and 
the efficiency of absorption in the simulated environment. 



References 

1. Marsh, H. E., and Hutchison, J. J., "Prepolymer Functionahty Deter- 
mination Using a Model Polymerization System," in Supporting Re- 
search and Advanced Development, Space Programs Summary 37-48, 
Vol. Ill, pp. 95-99. Jet Propulsion Laboratory, Pasadena, Calif., Dec. 

31, 1967. 

2. Marsh, H. E., Jr., and Udlock, D., "Low-Modulus Propellant for Case- 
Bonded, End-Burning Motors," in Supporting Research and Advanced 
Development, Space Programs Summary 37-63, Vol. Ill, pp. 184^188. 
Jet Propulsion Laboratory, Pasadena, Calif., June 30, 1970. 



56 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Fatigue of Teflon Bladder Bag Materials 

E. F. Cuddihy 

Propulsion Division 



A correlation between fatigue and stress-strain behavior of Teflon mate- 
rials was observed during a study of the fatigue properties of liquid pro- 
pellant expulsion Teflon bladder bag materials. This correlation requires 
only the knowledge of the ultimate breaking stress of the materials in order 
to obtain an estimate of the fatigue properties, and permits a rapid assess- 
ment of the expected fatigue behavior of candidate materials for bladder 
bags from only a comparison of their ultimate breaking stress. The general 
principles of this method of fatigue analysis is discussed, along with the 
recognition that this technique should have general application for other 
polymeric materials where stress-strain behavior is comparable to Teflon. 

Introduction 

Bladder bags prepared from a standard Teflon film laminate and 
employed as liquid propellant expulsion devices were failing from the 
formation of tears and cracks near an aluminum seal ring which forms 
the mouth of the bag. The failures were occurring when the bags were 
filled with Freon-TF and isopropyl alcohol, employed as substitute fuels, 
and then vibrated during a simulated launch test. From a consideration 
of the conditions imposed on the bags during test, four factors believed 
most critical in contributing to the failures were identified for study: 
(1) flex fatigue, (2) biaxial stresses, (3) solvent sensitivity, and (4) crystal- 
linity. The results of that study demonstrated that the primary cause for 
failure of standard laminate was its sensitivity to solvent stress-cracking 
(References 1 and 2), and that the bladder bags failed for that reason. 
A new material designated co-dispersion laminate was found to be 
insensitive to solvent stress-cracking and has replaced the standard 
laminate material used in construction of JPL Teflon bladder bags. 

This article describes the flex fatigue properties of both standard and 
co-dispersion laminate materials. The study of these properties resulted 
in a method of fatigue analysis which should have general application. 
The concepts of the method and the fatigue properties of standard and 
co-dispersion laminate materials in particular are presented. 



57 



Bladder Construction 

The construction of the bladder bags is detailed in Figure 1. Standard 
laminate is constructed in two plies, one of FEP 120 and the other of 
TFE 30. Co-dispersion laminate is constructed in three plies; an inner 
ply consists of FEP 9511 while the two outer pUes are formed from a 
co-dispersion of 80% TFE and 20% FEP 9511. 



(a) STANDARD LAMINATE 
FEP 120 
@ TFE 30 




0.0127 cm (0.005 in.) 
0.0127 cm (0.005 in.) 



(b) CO-DISPERSION LAMINATE 
CO-DISPERSION 



80% TFE 30/20% FEP 951 1 \^^^ 
FEP 951 




0.00762 cm (0,003 in.) 

0.01016 cm (0.004 in.) 

// 0.00762 cm (0.003 in.) 



TFE = TEFLON (DU PONT TRADEMARK) 

FEP = FLUORINATED ETHYLENE PROPYLENE COPOLYMER (DU PONT TRADEMARK) 

Figure 1. Bladder construction details 



Fatigue Properties 

Experiment 

The fatigue properties of the Teflon materials were measured by cycli- 
cally stretching specimens on an Instron test machine to constant load 
and then correlating the number of cycles to failure with stress. For this 
study, dumbbell specimens of 0.0254-cm (0.010-in.)^ thickness, 0.635-cm 
(0.250-in.) width, and 3.175-cm (1.25-in.) gage length were tested on the 
Instron operating at a crosshead speed of 0.423 cm/s (10 in./min). 

Fatigue Results 

The fatigue data for both standard and co-dispersion laminate ma- 
terials are plotted in Figure 2 as the log of cycles to failure versus the 
maximum stress applied during the fatigue test. The data curve for the 
co-dispersion laminate is linear while curvature and a plateau are ob- 
served in the data curve for the standard laminate. This departure from 
linearity is believed to be caused by the tendency of standard laminate 



iWhere applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents 
the measured or calculated unit. 



58 









1200 


1800 2400 3000 3600 4200 4800 




10^ 


- 


1 


" 1 1 1 1 1 1 

,N TFE AND fEP (REFERENCE 3) 

'^ \ O STANDARD LAMINATE 
\ ''v n CO-DISPERSION LAMINATE 
\ ^s EXTRAPOLATION 


< 




10^ 


- 


1 


\ \ 
\ \ 


—I 
u 
> 


10= 


- 




0"0^ nV 




102 


- 




\ \ 




loi 


- 




\ \ ' 




10° 




1 


, V. \_ 



STRESS, N/cm' 

Figure 2. Fatigue properties of Teflon bladder bag materials 

to delaminate during the fatigue testing. This point will be discussed 
later. 

Both curves tend to converge to a common point near 10' cycles and 
to intercept the axis for one cycle at a stress vs^hich corresponds to their 
ultimate breaking stress (Figure 3). The convergence point at about 
965-N/cm^ (1400-psi) stress corresponds to the location on their stress- 
strain curves (Figure 3) where departure is observed from the initial 
linear relationship between stress and strain. This common convergence 
point has also been observed for fold fatigue studies (Reference 3) on 
FEP and TFE and has been defined as a fatigue endurance limit (this 
data is reproduced in both Figures 2 and 4). 

These results demonstrate the existence of a correlation between 
fatigue properties and stress-strain behavior. For stresses within the 
linear portion of the stress-strain curve, fatigue failure occurs at about 
W cycles. But for stress exceeding those for linear behavior, i.e., in 
excess of the fatigue endurance limit, the number of cycles to failure 
decreases with increasing stress and the curves terminate at one cycle 
with a stress corresponding to the ultimate breaking stress. Thus, knowing 
the ultimate breaking stress, the fatigue properties can be predicted. 



59 



3500 


1 1 


' 


- 


3000 


- 


A 








^/ BREAK— ( 


- 


2500 


CO-DISPERSION LAMINATE^/ 


/ X 




2000 


"^^^ 


-'Standard laminate 




1500 


f 




- 


1000 


^ LOCATION OF DEPARTURE 

^^-""^ OF STRESS-STRAIN 

RESPONSE FROM LINEARITY 






500 











1 1 


1 1 





3000 



- 2000 



1000 



100 



200 300 

STRAIN, % 



400 



500 



Figure 3. Stress-strain curves 



60 









1000 


1100 1200 1300 1400 




1500 




108 







1 1 1 1 




1 




10^ 




D 


FATIGUE ENDURANCE LIMIT — ^ \ 








10* 


- 








- 


< 










\ 




o 


10^ 


- 








~ 


U 
>- 








FAILURE MODE 


\ 










D FEP; CRACKS 














TFE: YIELDS, DOES NOT BREAK 








10^ 


- 








- 




10= 


- 






} 


i 




102 






1 1 1 1 1 


1 





650 700 750 



) 850 900 950 1000 1050 
STRESS, N/cm^ 



Figure 4. Fold fatigue of TFE and FEP (reproduced 
from data in Reference 3) 



61 



Delamination of Standard Laminate 

AH specimens of standard material delaminated during the fatigue 
testing, with the extent of delamination apparently reflected in the 
behavior of the data curve. For the cycle region above the plateau, sub- 
stantial delamination was observed while negligible delamination was 
observed in the cycle region below the plateau. The plateau presumably 
occurs as the result of a transition from extensive delamination at high 
cycles to negligible and no delamination at low cycles. Delamination 




1600 
STRESS, N/cm 



2400 2800 



Figure 5. Comparison of actual standard laminate fatigue data with 
expected behavior 



62 



not only accounts for the departure of the standard laminate fatigue 
curve from linearity but also results in a substantial reduction in resist- 
ance to fatigue failure. This can be seen in Figure 5, where the fatigue 
curve is reproduced for this material along vi'ith the linear relationship 
expected for the absence of delamination. 

One additional observation can also be made from Figure 5. The 
points above the plateau extrapolate to the 1-cycle line at an ultimate 
breaking stress of 1792 N/cm^ (2600 psi). This value would presumably 
be obtained for a standard material delaminating during a uniaxial 
stress-strain measurement. This same value of ultimate stress was mea- 
sured for standard materials which were tested while completely 
immersed in Freon-TF and heptane solvents (Reference 1), while ex- 
posure to isopropyl alcohol had an intermediate value near 2137 N/cm^ 
(3100 psi). This suggests that part of the mechanism contributing to the 
solvent sensitivity of standard laminate may be a tendency to be de- 
laminated by solvents. 

Conclusion 

The linear relationship between fatigue cycles and stress provides a 
simple method of fatigue analysis for Teflon materials. Given the ultimate 
breaking stress and the fatigue endurance limit, the fatigue properties 
can be predicted. Further, since the fatigue endurance limit is apparently 
common, a rapid assessment of the fatigue behavior of various Teflon 
materials can be made from only a comparison of the ultimate breaking 
stresses. Similarly the effect of environmental or other factors on fatigue 
properties can be inferred from their effect on the ultimate properties. 

These considerations should also be applicable to materials having 
similar stress-strain characteristics as Teflon. These would include other 
crystalline polymers, such as polyethylene, and many block and graft 
copolymers including segmented urethanes. 



References 

1. "Study of the Effects of Solvent on Mariner Mars 1971 Liquid Pro- 
pellant Expulsion Teflon Bladder Bags," in Flight Frojects, Space 
Programs Summary 37-65, Vol. I, pp. 40-42. Jet Propulsion Labora- 
tory, Pasadena, Calif., Sept. 30, 1970. 

2. "Effect of Solvent on the Biaxial Properties of Liquid Propellant 
Expulsion Teflon Bladder Bags," in Flight Projects, Space Programs 
Summary 37-66, Vol. I, pp. 14-21. Jet Propulsion Laboratory, Pasa- 
dena, Calif., Nov. 30, 1970. 

3. Design and Engineering Data on Teflon Fluorocarbon Resins, E. L 
DuPont de Nemours and Co., Wilmington, Del. (undated). 



63 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Liquid-IVIetal MHD Power Conversion 

D. J. Cerini 
Propulsion Division 



A liquid-metal magnetohydrodynamic (MHD) power converter has been 
successfully operated with the generation of ac electrical power. Gaseous 
nitrogen is used to produce the closed-cycle flow of the liquid-metal (NaK) 
working fluid through the MHD generator where the fluid kinetic energy is 
converted to electrical energy. In this article the operational characteristics 
of the converter are given and the results of the current series of tests are 
discussed. 



Introduction 

Liquid-metal magnetohydrodynamic (MHD) power conversion (Refer- 
ence 1) is being investigated as a power source for nuclear-electric pro- 
pulsion. A liquid-metal MHD system has no moving mechanical parts 
and operates at heat-source-temperatures between 1200 and 1400 K. Thus, 
the system has the potential of high reliability and long lifetime with the 
use of readily available containment materials such as Nb-l%Zr. 

NaK-Nitrogen Converter 

The NaK-nitrogen test system to evaluate the electrical and hydraulic 
characteristics of a liquid-metal MHD converter has been successfully 
operated with the generation of ac electrical power. An output of 1.0 kW 
at 120 V and 350 Hz has been obtained in early tests with low generator 

currents. 

The converter is shown in Figure 1. Runs are started by feeding nitro- 
gen at 2.5 kg/s to the 1600-orifice NaK-nitrogen mixer. NaK is then 
injected from a nitrogen-pressurized start-tank at 75 N/cm^ and 40 kg/s. 
NaK is also supplied to the mixer through a pressure regulator at 5 kg/s 
from a 650-kg NaK supply under 150-N/cm- nitrogen pressure. The 
added NaK increases the circulating liquid flow rate and causes the 
nozzle inlet pressure to increase. When the pressure reaches the value 
for which the regulator is set, the regulator throttles the flow back to an 



64 




o 



'•1 r'k"' 



V 




z 

—J 


O ti; -J 


h- 


_j " 


VI 




3 




T^ 




X 

UJ 


z^ 


/ 




UJ 


O-" 


o 


O Q 


o 


Slii 



N 
N 
O 

z 

\ 




Q 
5 



3 



^ 



3 
DO 



65 



amount equal to that lost with the nitrogen and collected in a mist sepa- 
rator. The main problem encountered in startup has been establishing 
reasonably uniform pressure of the Mach 2 to 4 NaK-nitrogen flow in 
the generator channel. If the nitrogen flow to the nozzle is too high, a 
shock forms in the generator channel upstream of the diffuser, and pres- 
sures can reach 140 N/cm^ in the downstream part of the generator. If 
the nitrogen flow is too low, a shock forms at the capture slot leading 
to the generator, reducing the fluid power available and increasing the 
NaK flow to the mist separator. 

After startup, which requires about 20 s, adjustments can be made in 
the nozzle inlet pressure and in the nitrogen flow rate to reach various 
flow conditions for generator operation. A nozzle inlet pressure of 
103 N/cm- and nitrogen flow rates between 1.8 and 2.5 kg/s are cur- 
rently being used. The NaK flow rates range from 47 to 62 kg/s. 

The ac induction generator is then started by bringing up the alternator 
field. The six traveling-wave phases and the downstream compensating- 
pole phase are connected to capacitors and resistors of the desired values. 
The upstream compensating-pole phase is connected across the alternator 
since this phase requires power input; capacitance is still provided for 
the reactive power requirement. (The alternator can be replaced by trans- 
former coupling to the other phases, but the present arrangement pro- 
vides more positive control of generator current.) The currents in the seven 
self-excited phases rise in proportion to the current in the alternator- 
driven phase. When the approximate desired current levels are reached, 
the final trimming of current amplitudes and phase angles is done by 
adjusting variable transformers connecting the capacitors and resistors to 
the generator. After the generator currents are satisfactorily adjusted, the 
phase power outputs (or input, in the case of the upstream, alternator- 
driven phase) are recorded, together with currents, voltages, phase 
angles, and flow parameters. 

The adjustment process has been found to be difficult and time- 
consuming. Changing the capacitance or resistance on one phase not only 
changes the amplitude and phase angle of the current in that phase, but 
also affects the currents in all of the other phases. A procedure is 
currently being developed to calculate the required capacitance and 
resistance changes in each of the eight phases to correct the current 
amplitudes and phase angles. 

Current Test Series 

The current test series has consisted of 14 NaK runs of 5- to 10-min 
duration with generator operation. The generator has operated qualita- 
tively as expected, with power output from seven phases and input to 
one, but the internal power output from the NaK to the coils has been 
only about 65% of that predicted. When the winding loss is subtracted. 



66 



the net output is only a fraction of the predicted value. The net output 
was 300 W at 15-A current in the traveling-wave phases. The predicted 
power output was 1150 W. The most likely explanation is low fluid 
conductivity as a result of the flow expansion in the generator channel. 
The predicted power was based on the assumption that the flow in the 
generator channel would be at the same pressure (25-70 N/cm-) and 
same gas-liquid volume ratio (0.3-0.6) as the flow leaving the upstream 
diffuser. In the NaK runs the generator channel pressure was only 
10 N/cm^ and if, in addition, the flow expanded to uniformly fill the 
channel, then the volume ratio was in the range 1.5-2.0, which would 
reduce the conductivity sufficiently to account for the low output power. 

Empty channel tests conducted prior to the current test series indicated 
that the unexpectedly high stator losses in the generator are due to eddy 
currents in the coils caused by the field perpendicular to the flat strip 
coil turns. 

During the NaK tests an insulation failure occurred in one of the coils 
as the generator voltage was being raised above the 90-V level. The fail- 
ure had the effect of shorting nine turns on the upstream C-phase coil 
which increased the coil losses by 400 W and canceled the net output 
power. 

The shorted turns have been removed from the coil. In order to main- 
tain constant ampere-turns in both C-phase coils, the 31-turn coil is ex- 
cited by the 40-tum coil through a current transformer. 

Testing has resumed, and an output of 1.0 kW has been obtained. 



Reference 

Elliott, D. G., Hays, L. G., and Cerini, D. J., "Liquid-Metal MHD 
Power Conversion," in Supporting Research and Advanced Develop- 
ment, Space Programs Summary 37-51, Vol. Ill, pp. 120-124. Jet 
Propulsion Laboratory, Pasadena, Calif., June 30, 1968. 



67 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Design and Developmeot of a 66-W/kg, 
23-ni^ Roll-Up Solar Array 

W. A. Hasbach 



Guidance and Control Division 



Future space missions will require greater power output, lighter weight, 
and decreased stowed volume for solar arrays. To meet these requirements, 
a program was initiated to develop the technology for a roll-up solar array 
by preparing a detailed design, performing the associated analyses, fabri- 
cating an engineering development model, and subjecting the engineering 
model to a comprehensive test program consisting of both environmental and 
developmental tests. The design and testing of the 66-W/kg (30-W/lb),i 
23-m° (250 ft") roll-up solar array developed during this program is de- 
scribed in this article. 



introduction 

Future space missions will require greater power output, lighter weight, 
and decreased stowed volume for solar arrays. To meet these require- 
ments, a program was initiated to develop the technology for a roll-up 
solar array by preparing a detailed design, performing the associated 
analyses, fabricating an engineering development model, and subjecting 
the engineering model to a comprehensive test program consisting of 
both environmental and developmental tests. The design chosen is adapt- 
able to a variety of vehicle configurations and missions, including solar 
electric propulsion for unmanned planetary exploration and the manned 
space station for Earth orbiters. 

Description 

The design of the array was based upon the results of an earlier feasi- 
bility study by the General Electric Company (Reference 1). With this 



^Where applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents the 
measured or calculated unit. 



68 



design, a 23-m- solar cell module area would be stored on drums until 
deployment of the array after launch. The array, in its fully deployed 
configuration, is illustrated in Figure 1. The dimensions of each panel 
are 1.17 m (46 in.) X 10.21 m (402 in.). 

The engineering test model is representative of a flight-type design, 
except for a hmited solar cell coverage; 4000 solar cells vi^ere bonded 
to the substrates, with the remaining area occupied by glass platelets to 
simulate the solar cell mass and interconnect bending stiffness. The loca- 
tions of the various components on the engineering test model are shown 
in Figure 2. The weight breakdown for the model is as follows: 



Component 


Weight, kg 


Array substrate assemblies 


10 

10 


532 
596 


Solar panel actuator 


5 


321 


Storage drum assemblies (2) 


7 


983 


Drum-to-center-support mounting hardware 





059 


Center support 





603 


Leading edge member 





386 


Leading-edge-member support brackets (2) 





099 


Outboard end supports (2) 


1 


860 


Total 


37 


439 



Based on the above weights, the array power-to-weight ratio is 67 W/kg. 
This ratio is based on the ability of the array to generate 2500 W of 
power at 328 K (55 °C) under "air mass zero" illumination and within 
±0.1745-rad orientation with the Sun at 1.49599 X 10* km (1.0 AU), 
compared to a power-to-weight ratio of approximately 22 W/kg for 
typical Mariner-type solar panels. Cell efficiency is specified by area 
performance of 107.6 W/m'^ (10 W/ft^) of gross module area. The cell 
selected to achieve minimum weight was 0.020 cm thick, 2 cm X 2 cm, 
with 3.8 cm^ of active area per cell. The calculated array power under 
these conditions is 2523 W at 102 Vdc. To arrive at the maximum power 
available at the electrical interface on the center support, the series resis- 
tance distribution losses in the array substrate bus strip, the slip ring 
(including line losses within the storage drum and center support), and 
the solar cell interconnect were taken into account. The effect of the 
combined series resistance loss is to reduce the maximum power by 57 W 
at an operating temperature of 328 K. 

The major components that form the power-producing system are 
described below. 



69 






i. 
'f 1 



.f. l>U:^i& 



^ 




Figure 1. Fully deployed solar array 



70 



Y - 



.-- .-.--Tv;;-. 



./ 



Figure 2. Solar array components 



71 



Array Substrate 

The solar cells are mounted on two flexible substrates of 0.005-cm 
Kapton H film. Tension in these two substrates is utilized to maintain 
the desired single-plane geometry and to establish the natural frequency 
of the deployed system above the required 0.04 Hz. The flight-type 
design calls for each substrate to support 6 circuits, each composed of 
12 series-connected modules (eleven with 20 series cells by 19 parallel 
cells and one with 22 series cells by 19 parallel cells). 

The substrate is fabricated from copper-clad Schjel-Clad L-7510 etched 
to form a conductor electrical bus strip system, with each circuit feeding 
into the main positive and negative bus. The bus in turn connects to the 
feed-through section of the drum and the slip rings. All connections from 
the cell side of the substrate to the bus strip system are made around the 
edges rather than through holes in the substrate. The exposed copper bus 
strips on the rear side of the substrate are covered with Kapton silicone 
pressure-sensitive tape. Foamed RTV 560 cushioning buttons are depos- 
ited on the rear side of the substrate at the comers of each solar cell. 
These buttons provide the required interlayer cushioning in the stowed 
configuration. 

Solar Panel Actuator 

The solar panel actuator is a Bi-Stem deployable boom unit designed 
and developed by Spar Aerospace Products, Ltd. The boom element, the 
component which provides the actuation force for deployment and forms 
the primary structure in the deployed configuration, has a nominal out- 
side diameter of 3.4 cm (1.34 in.). It is made up to two 301 stainless-steel 
strips, 10.2 cm (4 in.) wide and 0.018 cm (0.007 in.) thick, which are pre- 
stressed to form an overlapped tube in the deployed position. The boom 
is silver-plated on its outside surfaces to reduce the temperature gradients 
in the boom when one side is exposed to solar radiation and the other 
side is in shadow. 

Storage Drums 

The two storage drums in the system form the backbone of the stowed 
configuration. The drums rotate approximately 15 turns to deploy or 
retract the array. Each drum includes a shell, outboard end cap, inboard 
end cap, and edge guides. The drum shells are 1.196-m (47.10 in.)-long, 
0.081-cm (0.032 in.)-thick sheet magnesium rolled into a 20.32-cm (8-in.)- 
diameter cylinder, which is closed with a lap-butt joint utilizing 1.9-cm 
(0.75 in.)-wide strip of magnesium bonded with Epon 934. 

The inboard end cap assembly houses the two main bearings which 
allow the storage drum to rotate with respect to the support shaft. The 
constant torque negator spring motor, which provides the substrate pre- 
load force, is mounted on the inboard end cap with the output spool 



72 



coaxial with the main bearings. A shp ring assembly, which functions to 
transfer array power and signals across the rotary joint between the drums 
and the center support, is then mounted to the inboard end of this output 
spool. The outboard end cap serves as the supporting interface for the 
drum outer end during launch. It contains a tapered hole which mates 
with a tapered plug in the outboard end support. Two edge guide flanges 
are mounted on each storage drum to provide control forces to the sub- 
strate edge if required during retraction. 

Center Support 

The center support consists of a magnesium center tube, two machined 
magnesium end fittings, and two magnesium face sheets. The center tube 
is pinned to the end fittings, and the face sheets are riveted to the tube 
end fittings. One face sheet provides for the electrical connector installa- 
tion and, together with the other face sheet, transmits shear loads. The 
end fittings provide the interface pads for the vehicle structure and 
the solar panel actuator. 

Leading Edge Member 

The leading edge member is the structural element on the outer-most 
edge of the substrate. In the deployed configuration, this member trans- 
mits the 17.8-N (4-lb) substrate preload force from the array substrates 
to the boom tip. In the stowed configuration, the leading edge member 
functions to restrain the outer substrate wrap and to cage the Bi-Stem 
boom element. The tips of this member are supported by the outboard 
end supports, and the center section is supported from the actuator 
housing by two saddle-type brackets. The leading edge member is made 
up from two 1.27-m (50.1-in.)-long cylinders fabricated from 0.05-cm 
(0.020 in.) beryllium sheet bonded with Epon 934. The two cylinders are 
inserted into a center fitting and bonded in place. This fitting also 
houses two instrument bearings which mate with the stainless-steel boom 
post. These bearings decouple the array substrate from the Bi-Stem 
boom for rotation about the boom axis. 

Outboard End Support 

This arm carries the stainless-steel tapered plugs which interface with 
the outboard end cap and leading edge member. Attachment of the 
movable arm to the vehicle-mounted bracket is through a hinge joint. 
A torsion spring which mounts on the hinge pin furnishes 1130 N-cm 
(100 in.-lb) of torque in the stowed configuration. The release of the 
support is accomplished by a separation nut/separation bolt/bolt catcher 
combination. The torsion spring forces the movable arm to rotate about 
the hinge pin through an angle of approximately 0.17 rad. The storage 
drum and the leading edge member are thus released to permit deploy- 
ment of the solar panel actuator. 



73 



Testing 

The engineering test model was subjected to a comprehensive test 
program consisting of both environmental and developmental tests. The 

following tests were conducted: 

(1) Deployed dynamics tests to provide necessary data on the dynamic 
characteristics of the deployed array for use in a comparison with 
analytical data. Results of the comparison were used to verify the 
mathematical models generated in earher phases of the program or 
to provide information to improve the mathematical models. Dur- 
ing the tests, the array was deployed vertically downward in a 
vacuum chamber, and the system was excited with motion at the 
center support. Out-of-plane symmetric (Z-axis), out-of-plane anti- 
symmetric (torsional), and in-plane (Y-axis) excitations were 
performed. 

(2) Pyrotechnic-induced shock tests to measure acceleration levels on 
the array components resulting from the simultaneous firing of 
both separation nuts (each armed with two active squibs) on the 
outboard end supports. 

(3) Thermal-vacuum tests to measure response of the array under 
deployed transient, low-temperature stowed, low-temperature de- 
ploy and retract, stowed transient and high-temperature soak, and 
high-temperature deploy and retract conditions. 

(4) Acoustic noise test to monitor response of system exposed to 60 s 
of random incidence, reverberent sound with an overall sound 
pressure level of 150 dB. 

(5) Stowed vibration tests in Y-, Z-, and X-axes. The tests consisted of: 
(a) several low-level sinusoidal sweeps to set initial recording gain 
factors and to obtain array response to a constant-level base exci- 
tation input to determine amplification factors, (b) an acceptance- 
level sinusoidal sweep at two-thirds of the specification level to 
evaluate linearity of system response and to provide a final assess- 
ment of the risks associated with the full-level qualification input, 
(c) a sinusoidal qualification sweep, and (d) random noise test- 
ing with the same sequence (low-level, acceptance-level, and 
qualification-level testing). 

Test Performance 
Cell/Coverglass/Glass Platelet Breakage 

The percent of solar cell and coverglass- breakage resulting from the 
environmental test program was significantly greater than that for 



74 



the dummy glass platelets. Breakage followed the relative difference in 
individual element thickness, i.e., 



Item Total breakage, % 

0.007-cm coverglass 3.25 

0.020-cm solar cells 1.75 

0.028-cm dummy glass platelets 0.47 

The most severe environment for the coverglass and solar cells was 
the stowed vibration test. There is no breakage pattern to indicate a 
possible cause for the high proportion of damage in the case of the 
coverglass, although there are a few examples of parallel adjacent cover- 
glass as within a module row that have cracked in a direction parallel 
to the axis of the storage drum. This may be an indication of insufficient 
cushioning between the storage drum shell and the first wrap of solar cells. 

The results indicate that the cell/coverglass composite is not as resistant 
to damage as a corresponding glass platelet mass simulation that is 
0.028 cm thick. The 0.007-cm-thick coverglass cracked independently of 
the cell in many cases. Since some of the damage was sustained dur- 
ing the acoustic noise test, it is felt that a test of this type should be 
retained as a system test environment for future Hghtweight solar array 
assemblies. 

The thermal-vacuum tests represented the most severe environment 
for the dummy glass platelets. This may be explained by the fact that 
the areas of dummy glass were not temperature-controlled during the 
deploy and retract cycles and therefore were colder than the solar cell 
modules. Also, many localized areas of the dummy glass were affected 
by an overheating condition that occurred during the stowed high- 
temperature test. Either of these factors could account for the dispropor- 
tionate percentage of glass platelet breakage during these tests. 

Solar Panel Actuator Limit Switch Failures 

Three microswitches are required within the solar panel actuator to 
maintain the fully retracted, orbital retracted (10.16 cm from fully re- 
tracted), and fully extended positions. At the conclusion of testing, none 
of these switches were operable. Since their function was not vital, no 
effort was made to fix the switches. The redesign required for corrective 
action is considered minimum for future applications. 

Fatigue Cracking Near Leading Edge Member 

A fatigue crack 0.317 cm (% in.) long, near the leading edge member 
in the solar panel actuator rod outer element, was discovered while pre- 



75 



paring for a 35-cycle life demonstration following the stowed vibration 
test. No change in performance of the system or in the length of the 
crack was detected during or after the life demonstration. 



Slip Ring Resistance Changes 

At the beginning of the test program, the slip ring resistance remained 
constant as the storage drums turned during array deployment and re- 
traction. Some slip ring dynamic resistance change was first recorded 
during the low-temperature deploy and retract cycle. Similar fluctuations, 
along with a slight overall increase in resistance, were recorded during 
the high-temperature deploy and retract cycle. The first ambient deploy- 
ment following the stowed vibration test produced fluctuations in resis- 
tance which corresponded to the period of rotation of the storage drums. 
After 35 ambient deploy and retract cycles, the magnitude of these 
fluctuations in resistance had decreased. The periodic nature of the 
changes in resistance indicates the possibility of dirt on the power rings 
which was gradually removed by the brushes as the array was deployed 
and retracted during the 35-cycle life demonstration. There was no sig- 
nificant increase in the static resistance of the power rings as a result of 
the environmental test program. 



Marginal Performance of Storage Drum Negator Spring System 

The present storage drum negator spring system appeared marginal 
for rewrap of the array substrate during the low-temperature deploy and 

retract test. 



Reliability Demonstration 

At the conclusion of the total test program, the array was deployed to 
its full length and retracted 35 additional times to establish confidence in 
such items as cell interconnects, deployment/retraction components, and 
slip ring assemblies. In all, more than 100 deployment retraction cycles 
were performed during the term of this program. With the exception of 
the microswitch failures noted above, no anomalies were detected which 
could be attributed to rolHng and unrolling the solar cell substrates on 
the storage drums. During the performance of the deployment/retraction 
tests, the deployment boom was purposely offset from its center line in 
the plane of the substrate to determine the array's ability to rewrap 
uniformly. It was demonstrated in these experiments that a boom tip 
deflection of up to 21 cm can be accommodated without difficulty and 
uniform substrate wrapping will not be compromised. 



76 



Conclusion 

Since the array demonstrated its ability to survive the specified test 
program, the concept of this 23-m^ roll-up solar array w^ith a 66-W/kg 
power-to-weight ratio has been proven feasible. 



Reference 

1. Feasibility Study 30 Watts Per Pound Roll Up Solar Array Final Report, 
Report 68SD4301. General Electric Co., Philadelphia, Pa., June 21, 1968. 



77 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Large Spacecraft Antennas: New Geometric 
Configuration Design Concepts 

R. E. Oliver 
Engineering Mechanics Division 



Several unconventional approaches to the configurational design of high- 
gain microwave antenna reflectors are presented. These approaches provide 
means for improving the performance of nonfurlable antennas and for im- 
proving both aperture efficiency and stowed volume efficiency of furlable 
antennas. 

The first class of design approaches involves relatively minor modifica- 
tions of conventional dual-reflector (Cassegrain and Gregorian feed) an- 
tenna concepts. These modifications eliminate the loss of transmitted 
energy resulting from the reflection of energy back into the feed from the 
subreflector as well as the loss due to interception of rays by the subre- 
flector after reflection from the main reflector. 

The second class of concepts involves the use of a conical main reflector 
and multiple reflections from this main reflector and from one or more 
subreflectors. These concepts offer the advantage of relative ease of fabri- 
cation, inspection, and furlability associated with a single curvature 
(conical) main reflector. In addition, they provide configurations with 
very small diameter subreflectors, resulting in low aperture area blockage 
and small furled antenna diameters. 



Introdyction 

The objective of this activity is to develop the technology required to 
design, fabricate, and test large high-gain antennas for use on spacecraft. 
The initial phase of this program was devoted primarily to the evaluation 
of existing and new antenna concepts with respect to their potential 
application to antennas with diameters up to 30 m. 

The results of this comparative evaluation indicated that the Cassegrain 
feed paraboloidal antenna configuration may be applicable for antennas 
greater than 4 m in diameter, although the folding or furling of the 



78 



doubly cxirved paraboloidal reflector does present problems. It was also 
pointed out that significant RF losses are associated with the tendency 
to reflect energy back into the feed horn from the subreflector in con- 
ventional Cassegrain feed designs. Although this reflection back into the 
feed can be avoided by modifying the subreflector surface near the an- 
tenna axis, losses are still significant, particularly in the case of dual- 
frequency operation. A simple configuration design modification for 
Cassegrain feed paraboloidal antennas, which eliminates these losses even 
for dual-frequency operation, is described in the following section. 

The most promising concept evolved during the initial evaluation study 
is the conical Gregorian antenna conceived by Ludwig (Reference 1). 
The use of a conical main reflector offers several potential advantages 
in the areas of mechanical and structural design, fabrication, surface 
measurement, and furling. In addition, this concept exhibits excellent 
RF performance characteristics. 

The principal disadvantage of the conical Gregorian antenna is the 
relatively large diameter of the subreflector (0,4 to 0.5 times the outer 
diameter of the main reflector). Unless the subreflector itself is furlable, 
it appears that this concept is limited in spacecraft application to an- 
tenna diameters below about 10 m. 

Several new antenna geometrical configurations, all using conical main 
reflectors, are presented. These concepts retain many of the advantages 
of the conical Gregorian antenna concept associated with a conical main 
reflector. In addition, they provide a means for greatly reducing subre- 
flector diameters (e.g., to less than one-tenth the main reflector outer 
diameter). 

Modified Cassegrain Feed Paraboloidal Antenna 

A simple approach to prevent the reflection of energy back into the 
feed horn of a Cassegrain feed paraboloidal antenna and at the same time 
to efficiently utilize all the feed-horn energy is illustrated in Figure 1. 

In this modified Cassegrain feed paraboloidal antenna concept, a ray 
emanating from the feed F and essentially on the antenna axis is reflected 
by the subreflector at point C and by the main reflector at point D. This 
ray then grazes the subreflector at point E. Thus, all energy emitted by 
the feed is reflected usefully from the antenna (to the extent that the RF 
waves behave like optical waves). 

The main reflector surface geometry is generated by rotation about 
the antenna axis (through F and C) of an arc D-G of a parabola. The 
axis of this parabola is displaced from, but is parallel to, the antenna axis. 
The vertex of the parabola is at A, and its focus is at B. The subreflector 
surface geometry is generated by rotation about the antenna axis of an 



79 




ANTENNA AXIS 
(SYMMETRICAL) 



AXIS OF PARABOLA 



-AXIS OF HYPERBOLA 

Figure 1. Modified Cassegrain feed paraboloidai antenna 



MAIN 

REFLECTOR 




AXIS OF ELLIPSE 
OF PARABOLA 

SUBREFLECTOR 



FEED — ^ ^—ANTENNA AXIS 

Figure 2. !\^odified Cassegrain with ellipse-generated subreflector 



arc C-E of a hyperbola, the major axis of which passes through F and B. 
The subreflector thus produces an image of the point source feed F at the 
focus B of the parabola. The main reflector then "sees" an apparent ring 
source on the circle produced by rotating this focal point B about the 

antenna axis. 



Note that this modification involves no additional elements and no 
increase in complexity over a conventional Cassegrain feed paraboloidai 
antenna design. This concept does, however, provide efficient use of the 
feed energy, even for dual-frequency antennas. 



In concept, this modification is equally applicable to both Cassegrain 
and Gregorian feeds using subreflectors generated by arcs of hyperbolas 
or ellipses as illustrated in Figures 2 through 4. 



SO 



MAIN 
REFLECTOR 




SUBREFLECTOR 
ANTENNA AXIS 



|— FOCUS OF PARABOLA 
AND HYPERBOLA 



AXIS OF PARABOLA - 
AXIS OF HYPERBOLA - 



Figure 3. Modified Gregorian with hyperbola-generated subreflector 




ANTENNA AXIS 
SUBREFLECTOR 



Figure 4. IWodified Gregorian with ellipse-generated subreflector 

Multiple-Reffectioo Conical Antenna 

The basic principle of the multiple-reflection conical antenna concept 
is illustrated in Figure 5. The main reflector surface is a frustum of a 
cone with its apex at A and with a half cone angle 9. The subreflector 
surface is generated by rotation about the antenna axis (through A and 
F) of an arc B-C of a parabola. The vertex L and focus K of this pa- 
rabola lie on the cone with half angle 26 and with its vertex at A. The 
image F of this focus (as reflected in the main reflector cone) then lies 
on the anteima axis. The effective center of the feed is then placed at 
this focal point F. A ray leaving the feed center F and just grazing the 
subreflector at C is reflected by the main reflector at D, by the subre- 
flector at B, and again by the main reflector near D. This ray then 
emerges from the antenna parallel to the antenna axis. The outermost 
usable ray is traced in Figure 5, traveling the path F-J-C-E and then 
emerging from the antenna parallel to the antenna axis. Each ray thus 
experiences three reflections before emerging from the antenna. 

For geometrically exact and perfectly reflective surfaces, it is clear 
that all optical rays emanating from the feed between the cones with 



81 



AXIS OF 
PARABOLA 



IMAGE OF 
SUBREFLECTOR 
IN MAIN 
REFLECTOR 




■SUBREFLECTOR ^-FEED CENTER 

Figure 5. Multiple-reflection conical antenna 



REFLECTION OF 
MAIN SUBREFLECTOR 
vIN MAIN REFLECTOR 



- MAJOR AXIS OF PARABOLA 
■ FOCUS OF PARABOLA 



MAIN REFLECTOR 




MAJOR AXIS 
OF ELLIPSE 



J y IK 1 
_ .^ 1— 1 



ANTENNA AXIS 
(SYMMETRICAL) 



AUXILIARY 
SUBREFLECTOR ■ 



Figure 6. Multiple-reflection conical antenna 
with modified Cassegrain feed 

half angles a and p (Figure 5) will emerge from the antenna parallel to 
the antenna axis. Further, it is also easily shown that all path lengths 
of these rays from the feed center F to any plane normal to the antenna 
axis and to the right of point E will be equal. 



82 



As suggested in Figure 5, the diameter of the subreflector (through 
point B) can be much smaller than the outer diameter of the main 
reflector (through point E). 

It is also clear (again assuming geometrically exact and perfectly 
specularly reflective surfaces) that the performance of this antenna will 
be identical to that of a conventional focal point feed paraboloidal an- 
tenna, the generating parabola for which is shown through L', B', and 
C in Figure 5 and with its focus at F. Thus, this multiple-reflection 
conical antenna configuration represents, in a sense, an optically folded 
version of a conventional focal point feed paraboloidal antenna. 

This similarity between this concept and a conventional focal point 
feed paraboloidal antenna suggests that it will exhibit some of the dis- 
advantages of the latter. The feed horn, being relatively far forward 
from the vertex of the main reflector, requires long feed lines, resulting 
in feed line losses. Further, as suggested above, all energy associated 
with rays emanating from the feed within the cone with half cone 
angle a is lost. 

Both of these disadvantages can be virtually eliminated by incorporat- 
ing the modified Cassegrain feed described above. One possible version 
of the multiple-reflection conical antenna with a Cassegrain feed is 
shovTOi in Figure 6. 

In this version of the multiple-reflection conical antenna, the main 
subreflector surface is generated by rotation about the antenna axis of 
a segment A-B of a parabola, the axis of which passes through K and C 
and with its focus at C. The reflection in the conical main reflector of 
this focus C is at C, which lies above the axis of the antenna. An auxil- 
iary subreflector surface is generated by rotation about the antenna axis 
of a segment D-E of an ellipse, the major axis of which passes through 
the effective center F of the feed and through the point C. F and C 
are the foci of this generator ellipse. Thus, an effective ring source is 
created on the circle generated by rotating the point C about the 
antenna axis. 

Considering the geometrical properties of ellipses, parabolas, and 
cones, it is clear that all (optical) rays emanating from the feed within 
the cone with half cone angle a will ultimately radiate from the antenna 
parallel to the antenna axis. All path lengths associated with these rays 
from the feed F to any plane normal to the antenna axis and to the right 
of point H (Figure 6) are equal. 

For geometrically exact and perfectly specularly reflecting surfaces, 
the performance of this antenna would be identical to that of an antenna 
with a main reflector surface generated by rotation about the antenna axis 
of a segment A'-B' (Figure 6) of a parabola with its focus at C, with a 



83 



point source feed at F, and using the auxiliary subreflector shown in 
Figure 6 as the only subreflector. Thus, this version of the multiple- 
reflection conical antenna represents an optically folded version of a 
more nearly conventional antenna configuration (i.e., that of Figure 1). 

Other versions of the multiple-reflection conical antenna concept are 
obvious from this analogy between Figure 6 and Figure 1. For instance, 
conical sections can be superimposed on Figures 2, 3, and 4 to illustrate 
the optical folding of these configurations into multiple-reflection con- 
ical antennas. 



Conclusion 

The modified Cassegrain feed paraboloidal antenna concept provides 
a simple means for eliminating RF energy losses associated with small 
illumination angles in conventional Cassegrain feed antennas. The appli- 
cation of this concept may improve the performance characteristics of such 
antennas, particularly those which must operate with two RF frequencies. 

The multiple-reflection conical antenna concepts described above re- 
tain many of the advantages of the conical Gregorian antenna cited by 
Ludwig (Reference 1). In addition, proper choices of geometric parame- 
ters (e.g., cone angle and focal length of the subreflector surface gener- 
ator parabola) can provide configurations with very small diameter 
subreflector elements. For instance, a parametric analysis of the basic 
configuration shown in Figure 6 indicates that a ratio of subreflector 
outer diameter to main reflector outer diameter as small as 0.06 can be 
realized. This configuration would then produce a direct subreflector 
blockage of only 0.36% of the main reflector projected area (as com- 
pared with 16 to 25% blockage associated with the conical Gregorian 
concept). 

Other important antenna design criteria may, of course, preclude the 
practical achievement of such low blockage ratios, particularly in smaller 
diameter or low radio-frequency antennas. For instance, the subre- 
flector diameter should, in general, be many (e.g., 10 or more) wave- 
lengths associated with the operating radio frequency. It may be 
necessary, also, to avoid placing a reflective surface less than several 
RF wavelengths from the focal ring (e.g., point C in Figure 6) of the 
auxiliary subreflector. 

It is also recognized, of course, that the introduction of additional 
reflecting surfaces tends to increase performance degradation resulting 
from deviations of reflecting surfaces from their ideal geometries. This 
potential disadvantage is compensated, at least partially, by the relatively 
small diameters of the subreflectors. In general, the smaller the overall 
dimensions of a reflecting surface, the easier it is to maintain small 



84 



manufacturing tolerances and the smaller will be the thermal distortions 
(for a given thermal environment). 

The concepts presented above have been considered only from the 
standpoint of basic geometric feasibility and under the assumption that 
the RF vi^aves behave essentially as optical waves. Practical applications 
of these concepts would, of course, require more detailed comparative 
evaluations with respect to RF performance, ease of fabrication, struc- 
tural feasibility, weight, cost, reliability, and integrability with spacecraft 
systems. Effort is currently being directed toward the design, fabrication, 
and RF testing of a small (approximately 1-m diameter) model based on 
the version shown in Figure 6. 



Reference 

1. Ludwig, A. C, and Hardy, J., "Spacecraft Antenna Research: Prelim- 
inary RF Test of Conical Gregorian Antenna," in Supporting Research 
and Advanced Development, Space Programs Summary 37-63, Vol. Ill, 
pp. 42-46. Jet Propulsion Laboratory, Pasadena, Calif., June 30, 1970. 



85 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Aotenna Support Structure Aperture Blockage Loss 

A. Ludwig 
Telecommunications Division 



Loss in antenna gain caused by support structure aperture blockage is 
probably the most difficult loss factor to measure or calculate. In this 
article the loss is determined experimentally for aluminum and fiberglass 
structural configurations, and empirical formulas are developed to calculate 
the loss for other similar configurations. Experimental and analytical data on 
the X-band RF transmission characteristics of thin fiberglass sheets are pre- 
sented. It is concluded that fiberglass structures are far superior for mini- 
mizing gain loss. 



Introduction 

The feed or subreflector of an antenna must be attached to the reflec- 
tor, and typically the required support structure blocks some of the RF 
energy, causing a loss in antenna gain. This effect is called blockage loss 
and has been considered by several authors (e.g., References 1, 2, and 3). 
The direct experimental determination of this loss is very difficult since 
it is necessary to (1) determine the total efficiency loss of the antenna by 
an absolute gain measurement, and (2) evaluate all loss factors other than 
the blockage loss. Both of these steps are difficult and typically introduce 
tolerances comparable to or larger than the effect being measured. Accu- 
rately calculating the loss for a conventional truss structure is even more 
difficult. 

In this article, the loss is experimentally determined by comparing the 
gain of the antenna using a given configuration with the gain of the an- 
tenna using a configuration for which it is possible to accurately deter- 
mine the loss a priori. The results are then used to develop empirical 
formulas for loss calculations, and to demonstrate that two types of fiber- 
glass structures are far superior to aluminum structures for minimizing 
gain loss. 



86 



Support Configurations and Analysis 

Two basic types of configurations were considered: a conventional 
strut-type structure as shown in Figure 1, and a single large cylindrical 
shell as shown in Figure 2. The structural members used in the first con- 
figuration consisted of fiberglass or aluminum tubes of different diame- 
ters; the second configuration used only one cylinder made of 0.38-mm 
(0.015 in.)'-thick fiberglass. 

The analysis of the second structure, shown schematically in Figure 3, 
is relatively simple. For low transmission loss, multiple reflections within 
the cylinder may be neglected; also the radius of curvature is large com- 
pared to a wavelength, so the net loss is closely approximated by the loss 
of a plane wave incident on an infinite fiberglass sheet of the same 
thickness. 

To determine the dielectric properties of the fiberglass at the 8448-MHz 
test frequency, several samples were tested using a method reported pre- 
viously (Reference 4) in which the test sample is inserted across a section 
of WR 112 waveguide. As described in the above reference, at 8448 MHz 
this is equivalent to having a plane wave incident at 0.672 rad (38.5 deg) 
from the normal to the surface, vidth the E-field normal to the plane of 
incidence. The test results for three thicknesses are shown in Figure 4. 
Also shown are calculated results for three values of the dielectric con- 
stant e, which were obtained from a computer program developed by 
Otoshi.^ It is seen that for a dielectric constant of 5.0, the computed data 
matches the measured data reasonably well. This value of the dielectric 
constant is in the correct range for fiberglass (Reference 5). Using this 
value, the loss of a fiberglass sheet may be calculated for various angles 
of incidence as given in Figure 5. 

To confirm this data, the transmission loss was directly measured by 
inserting a fiberglass sheet between two horn antennas. Compared to the 
waveguide measurement, this technique has the advantage of allowing 
measurement of either polarization for any angle of incidence, but has 
the disadvantage of diffraction effects which can be difficult to estimate. 
However, the measured data agrees very well with the computed data as 
shown in Figure 5, resulting in high confidence in the data. 

For the support configuration shown in Figures 2 and 3, the angle of 
incidence y is 0.524 rad (30 deg). For either the case of linear or circular 
polarization (due to the circular symmetry of the structure), the loss will 



iWhere applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents the 
measured or calculated unit. 

^Otoshi, T. Y., private communication. 



87 




Figure 1. Strut support structure 




X - 




Figure 2. Cylindrical shell support structure 



88 



FIBERGLASS CYLINDER 
0,38-mni (0.015-in.) WALL THICKNESS 




Figure 3. Cylindrical support structure for conical antenna subreflector 

be the rms average of the values for E-field normal, and E-field perpen- 
dicular to the plane of incidence. Using the information in Figure 5, the 
loss is calculated to be 0.08 dB. There is an additional 0.05 dB of loss 
due to three joints where the thickness is doubled. The net loss of the 
structure in Figure 2 is therefore 0.13 dB. A conservative estimate of 
the tolerance on this value is ±0.08 dB. 

The analysis of the strut structure shown in Figure 1 is not as straight- 
forward or nearly as accurate as the cylinder analysis. In general, loss 
due to aperture blockage arises from two factors: (1) a fraction of the 
aperture is shadowed, reducing the effective aperture area of the an- 
tenna; and (2) a fraction of the radiated power is lost. To a first approxi- 
mation, these two effects are equal and if the fractional area blocked is 
AA, the blockage efficiency is given approximately by 



VB 



= (1 - AAY 



(1) 



Somewhat more sophisticated results are given in the References 1, 2, 
and 3, but the whole approach is based on such uncertain assumptions 
that it is not clear that anything more complicated than Equation 1 is 
justified. (The main questionable feature is that, typically, the structural 
members have dimensions on the order of a wavelength, but diffraction 



89 





0.01 0.02 


0.03 


0.04 


O.B 


' i 
(a) PHASE SHIFT 


1 


1 


0.6 


_ 








CALCULATED VALUES FORe 


<^ 


-^ 


0.4 


^^^\, 


0-^ 


-■^"^ 




MEASURED VALVES^ ^^^[^^-'''^ 


~ 


0.2 


z-^:^^^^^^^^^^ 




- 





,1*^^ 1 i 1 


1 





1.0 



0.6 



S 0.4 

2 
< 

0.2 



0.2 



0.4 0.6 

THICKNESS, mm 



0.8 



40 



-30 



- 20 



1 1 

(b) TRANSMISSION LOSS 




1 / 


' 1 


CALCULATED VALVES FORf 


= b/ 


Oy/^ 


/ 


/ 


Sy^ 




/< 


MEASURED VALUES^ y/^ ^ 


4,-^ 










1 





Figure 4. RF effect of fiberglass sheet in WR 112 
waveguide at 8448 i^Hz 



z 
o 




0.2 0.4 0.6 0.8 1.0 1.2 1.4 

ANGLE OF INCIDENCE, rod 



Figure 5. Transmission loss vs angle of incidence for fiberglass 
sheets of two thicknesses 



90 




Figure 6. Area shadowed by strut structure 

effects are not considered.) One modification of this application to Equa- 
tion 1 has been suggested (Reference 6) which does appear to be useful; 
the blocking structure is assumed to be partially transparent with an 
opacity coefficient a, and an effective blocked area is defined by 



so the loss is given by 



AAeff = ffAA 



5?B = (1 - a^AY 



For a perfect conductor, neglecting diffraction effects, one would expect 
the opacity factor to be 1.0. For a fiberglass tube, the opacity may be 
estimated by averaging the transmission loss and loss due to phase shifts 
over various angles of incidence. Based on this very rough approach, for 
a 0.51-mm (0.020-in.) wall tube with a wave incident at 0.524 rad (30 deg), 
one would expect an opacity of about 30%, and for a 0.89-mm (0.035-in.) 
wall, an opacity of about 65%. However, the tolerance on these estimates 
is near a factor of 2. 

The blocked area ^A is defined as 'the projection of the optical shadow 
of the support members on the aperture area of the antenna. Referring 
to Figure 6, which is a head-on view of the antenna, if the struts of 



91 



diameter d were all parallel to the axis of the antenna, and were located 
on a circle of diameter D, then we would have 

ttD - 8d 

aA = (4) 

TrLf 

In the actual test antenna configuration shown in Figure 1, the struts are 
not parallel to the axis, but Equation 4 is still a good approximation for 

the area. 



Experimental Results 

The various structures were used to support the subreflector of the 
conical antenna as shown in Figures 1 and 2. The relative gain of the an- 
tenna with the various structures was then measured using a bolometer 
detector and HP 415 meter (1800-Hz signal modulation). Since the sup- 
port structure loss is knoMoi for the case of the cylinder, this was used as 
the normalization to determine the absolute loss of the other structures. 

Using this normalization, where the loss of the cylinder is taken to be 
—0.13 dB, the values shown in Table 1 are obtained. The indicated toler- 
ance of ±0.10 dB includes measurement errors as well as the tolerance 
on the calculated cyHnder loss. Also shown in Table 1 are the blocked 
areas for the various cases. Using values for the blocked area and the 
loss. Equation 3 may be used to empirically determine the effective 
blocked area and values of a, which are also shown in Table 1. It is 
seen that for aluminum tubes of this size the effective area is substan- 
tially larger than the actual area, resulting in an opacity greater than 
the expected value of 1.0, whereas the effective area of the thin fiber- 
glass tubes is much less than the actual area, and the opacity is less 
than the expected value. Of course, in both cases, the expected opacity 

Table 1. Measured blockage loss and empirical values of effective opacity 
Aliimmum stmts Fiberglass struts 



Case 1.27-cm-di£un, 5.72-cm diam, 

1.27-cmdiam 3.81-cm diam 0.09-nun- O.Sl-mm- 

thick wall thick waU 

Measured blockage 0.52 ± 0.10 2.03 ± 0.10 0.10 ± 0.10 0.29 ± 0.10 

loss, dB 

Fractional blocked 3.9 11.6 3.9 17.4 

area, % 

Effective blocked 5.8 ± 1.0 20.8 ± 0.9 1.1 ± 1.1 3.3 ± 1.1 

area, % 

Opacity a 1.5 + 0.3 1.8 ± 0.1 0.3 ± 0.3 0.19 ± 0.06 



92 



Table 2. Calculated blockage loss for TOPS high-gain antenna 



Case 



Almninum stmt 
(3.81-cm diam) 



Fiberglass strut 
( 5.72-cm-diain, 
O.Sl-nunwall) 



Fiberglass 

cyKnder 

( 0.38-inin wall ) 



Fractional blocked 
area, % 


8.7 


12.0 


100 


Opacity a 


1.8 


0.19 


0.016 


Effective blocked 
area, % 


15.7 


2.3 


1.6 


Expected 
blockage loss, dB 


1.5 


0.20 


0.14 



values were very rough estimates. Unfortunately, the estimated tolerance 
swamps out the value of a for the case of the small fiberglass tube, but 
in the other cases the value is reasonably well determined. These empiri- 
cal values of opacity may be used in Equation 3 to extrapolate the results 
to other antennas with similar configurations. For example, the loss of 
several proposed support structure configurat:^ons^ior the Thermoelectric 
Outer-Planet Spacecraft (TOPS) high-gain antenna are shown in Table 2. 



To compute the loss of a cylindrical support for a conventional parabo- 
loidal reflector is more difficult than the case of the conical reflector. For 
the conical antenna the angle of incidence is constant; for the TOPS 
paraboloidal reflector the angle of incidence varies as show in Figure 7. 
If we divide the antenna into several regions and take the angle of inci- 
dence as being constant within each region, approximate values of the 
voltage transmission coefficient * and relative phase shift A.^ may be ob- 
tained as given in Table 3. The relative phase shift is the difference 



FIBERGLASS CYLINDER 
0.38-mm (0.015-in.) 
WALL THICKNESS 




Figure 7. Cylindrical support structure for conventional paraboloidal 
antenna subreflector 



93 



■o 

c 

"f 

ID 

a, 
a 

5 o 
*■ 13 

q S 

Sg 

i| 

o ts 

6 a. 
E k 
<s o 

a, T^ 

g ^ 
.S o. 

in 0) 

E 

ID 

c 



!2 




C8 

"S 

S 8 

-3 g 

2 o 

a g 

ns o 



a 



= 60 



a 

a 
"p. 

.2 



-I M 







•a 



o 



05 


1-1 


m 


o> 


■>!l< 


(N 


rtl 


i-H 


^ 


>-l 


cq 


IjO 


O 


o 


o 



00 


00 


05 


i5 

Oi 


o 


o 


o 


o 



CO 



CO 



c4 



in 


CO 


lr~ 


1^ 


en 


a> 


» 


in 


OS 


02 


CD 


05 


05 


05 


CT> 


as 


o 


o 


O 


o 



en 
o 



r-( 
I 



a> 
in 

05 

d 



CD 

in 
I 



CD ■* 

t- 00 

as 05 

d d 






c» 

OS 


CD 
05 


00 


03 


o 


O 


o 


o 



g 



o 

CO 



o 
in 



o 



in 
in 



in 


in 


o 


"f 


t 


*Y 


in 


in 




oa 


CO 


■*i^ 



l-H CM 



94 



between the actual phase shift through the sheet for a given region and 
the average phase shift of all regions. The effective voltage transmission 
coefficient t is then given by t = * cos A<^. The net transmission coeffi- 
cient of the cone is then given by an area weighted rms average of the 
transmission coefficients 

rnet= Y.h'n + n)^A (5) 

all 
regions 

This yields a value of Tnet = 0.9841 for the data of Table 3, which cor- 
responds to the loss of 0.14 dB given for this case in Table 2. 

These results demonstrate the clear RF superiority of fiberglass struc- 
tures over the aluminum structures (all structures are mechanically nearly 
equivalent) for the TOPS antenna. 



Conclusion 

It has been experimentally determined that aluminum tubes 1-2 wave- 
lengths in diameter have an effective blockage area approximately l%-2 
times their physical area and that thin wall fiberglass tubes have an 
effective blockage area much less than their physical area. Both thin wall 
fiberglass tubes and large fiberglass cylinders are very good support 
structures for reducing gain loss. It should be noted that dielectric struc- 
tures have an adverse effect on the system temperature of very low noise 
receiving antennas, so although the fiberglass structures are very attrac- 
tive for relatively noisy spacecraft antenna systems, they are not neces- 
sarily attractive for low noise ground antennas. 



References 

1. Gray, C. L,, "Estimating the Effect of Feed Member Blocking on 
Antenna Gain and Sidelobe Level," Microwave J., pp. 88-91, Mar. 1964. 

2. Wested, J. H., "Shadow and Diffraction Effect of Spars in a 
Cassegrainian System," Report F2118. Microwave Laboratory, Danish 
Academy of Technical Sciences, Copenhagen, Denmark, Mar. 1966. 

3. Ludwig, A., "Efficient Antenna Systems: Aperture Blockage and Sur- 
face Tolerance Loss Calculations for Non-Uniform Illumination and 
Error Distribution," in The Deep Space Network, Space Programs 
Summary 37-41, Vol. Ill, pp. 89-90. Jet Propulsion Laboratory, 
Pasadena, Calif., Sept. 30, 1966. 



95 



References (contd) 

4. Woo, K., and Otoshi, T. Y., "Spacecraft Antenna Research: An RF 
Study of Reflector Surface Materials for Spacecraft Antennas," in 
Supporting Research and Advanced Development, Space Programs 
Summary 37-61, Vol. Ill, pp. 99-106. Jet Propulsion Laboratory, 
Pasadena, Calif., Feb. 28, 1970. 

5. Handbook of Chemistry and Physics, 50th Edition, p. E-66. Edited by 
R. C. Weast. Chemical Rubber Co., Cleveland, Ohio, 1969-1970. 

6. Potter, P. D., The Design of a Very High Power, Very Low Noise 
Cassegrain Feed System for a Planetary Radar, Technical Report 32- 
653. Jet Propulsion Laboratory, Pasadena, Calif., Aug. 24, 1964. 



96 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Interplex Modulatiori 

S. Butman and U. Timor 
Telecommunications Division 



In a conventional phase-shift-keyed/phase modulated (PSK/PM) system, 
the receiver tracks the frequency and phase of the carrier by means of a 
phase-locked loop and coherently demodulates the data. However, due to 
the inherent nonlinearity of the phase-modulation process, some power is 
transmitted as cross modulation, which reduces the useful available power. 
This article describes a new PSK/PM modulation scheme, called Interplex, 
which reduces the cross-modulation power loss. The scheme can be imple- 
mented in existing systems without significant hardware changes and ap- 
pears attractive in concept for improving the performance of deep space 
telecommunications systems. 



Introduction 

In conventional multichannel frequency-multiplexed telemetry systems, 
several independent binary data channels are combined, using biphase- 
modulated subcarriers, to phase modulate a single RF carrier signal. Such 
systems are called phase-shift-keyed/phase-modulated (PSK/PM). The 
receiver tracks the frequency and phase of the carrier by means of a 
phase-locked loop and coherently demodulates the data. Lindsey (Refer- 
ence 1) and Weber (Reference 2) analyzed the performance of such 
systems, which depends on the povt^er in the data sidebands as well as on 
the unmodulated component of the carrier. However, due to the inherent 
nonlinearity of the phase-modulation process, some power is transmitted 
as cross modulation, which reduces the useful available power. 

This article describes a new PSK/PM modulation scheme, called Inter- 
plex, which reduces the cross-modulation power loss, without affecting 
the basic structure of the conventional system. Thus, it can be easily 
incorporated into existing systems. It appears attractive in concept for 
improving the performance of deep space telecommunications systems. 



97 



Formulation 

The general form of the phase-modulated RF signal in a multichannel 

PSK/PM system is 



z(i) = V^sin M + ©(f)] (1) 



where P is the total average power, wc is the carrier frequency, and ®(t) 
is the phase modulation. In conventional PSK/PM systems, ® (i) is a linear 
combination of binary phase-shift-keyed sine-wave or square-wave sub- 
carriers. We will temporarily assume that the system bandwidth is suffi- 
ciently large to handle square-wave subcarriers, because sine-wave sub- 
carriers produce more cross-modulation loss and should be avoided. This 
of course may not be possible in very high data rate systems where band- 
width becomes a factor; however, the basic concepts are the same. 



When a binary data stream dn{t) = ±1 phase-shift-keys a unit ampli- 
tude square wave, sq (»„*) = ±1, of frequency &>„, the result is again a 

binary wave, s„(i) = ±1, 

Sn{t) = dn{t) sq («)„*) (2) 

and the phase modulation © it) in a conventional system is 

®{t) = ^enSn{t) (3) 



where TSI is the number of channels and the coefficients 9i, d^," ' , &n are 
the modulation angles or modulation indexes whose choice determines the 
power allocation for each channel, the power allocated to the RF carrier, 
and the power that goes into cross modulation. We will analyze in detail 
the two-channel system. A generalization to the multichannel case will 
be briefly discussed in the last section. 



Two-Chanrie! Conventional PSK/PM System 

When only two channels are involved, the phase-modulated RF signal is 



z(*) = [V^PiSiW + \/fP2S2(i)] cos (met) 

+ [V2P, + VlPe« Si(*)so(i)] sin {m,t) (4) 



98 



where 



Pi = P sin- di cos- 02 = power in channel 1 

Po =P cos- 9i sin^ 02 = power in channel 2 

Pc = P cos- Oi cos^ 62 = power in carrier 

Pcm = P sin- 9i sin^ dz = power in cross modulation 



(5) 



The cross modulation in the case of a two-channel system with square- 
wave subcarriers is simply the product of the two phase-shift-keyed sub- 
carrier waveforms Si ( f ) Ss ( * ) • 



A block diagram of the receiver for this system is shown in Figure 1. 
The voltage-controlled oscillator (VCO) is in the phase-locked-loop 
arrangement that tracks the carrier component and produces the coherent 
reference signal cos (act + ^), where ^ is the receiver phase error. When 
z{t) is multiplied by VE'cos {o>ct + <^) and the result is filtered to remove 
frequencies above oc, the result is a base-band signal of the form 



y(t) = l^/F^S^(t) + VP^S,{t)] cos,/, 

+ [VPc + -\/Pc^iSt(t)s2it)] sin^ -I- n,j{t] 
where n,j{t) is the additive gaussian white noise. 



TRANSMITTER 




V2F sin [oj^t + e{t) 



sq(uj,t) 



RECEIVER 



COs(tO t ~^4 



VCO 



DEMODULATOR 
ASSEMBLY 



DEMODULATOR 
ASSEMBLY 



CHANNEL 1 



CHANNEL 2 



Figure 1. Conventional two-channel system 



99 



The data signals di{t) and d^it) are recovered from y{t) by multipl)'- 
ing with locally generated coherent subcarriers sq (a>it) and sq (aot) and 
filtering or bit detecting. 

For a perfectly coherent system (<^ = 0), the efficiency of this system, 
measured in terms of the fraction of total power converted to data power, is 



1 



-V- (7) 



From Equation 5 the total power is 

P = P, + P, + Pc + Po 



since by Equation 5 



P1P2 
= P, + P, + Po+ -^ (8) 



P P 

Pom = -jf- (9) 



Since in the usual case, the requirement for data power in channel 1 results 
in Pc < Pi, it is clear that Pcm > P2. Thus, the cross-modulation loss 
exceeds the power in the second (low rate) channel and indeed increases 
when Pc is decreased. Therefore, the total power needed is minimized 
when Pern = Pc = \/P\PI = P* which corresponds to choosing 9^ + 62 = 
90 deg. Thus, the minimum total power is 

p* = p, + p, + 2\^p^.,= {^/K + VKy- (10) 

and the maximum efficiency is 



U/P' J- ^ /P'\2 ^ ' 



" ^ (1 + v^)^ ^^'^> 

where a = P2/P1 is the ratio of power in channel 2 to the power in 
channel 1. If both channels employ the same, or equally efficient, coding 
schemes, then a is also the ratio of data rates. However, in general, the 
lower rate channel could be more efficiently coded than the high rate link. 

Referring to Equation 12 it is evident that the conventional PSK/PM 
two-channel system cannot be 100% efficient unless a = 0, which corre- 
sponds to having a single channel (P2 = 0). For two equal channels, i.e., 
P, = Pi or a = 1, Pcm = P* = Po = Pi and the efficiency is at most only 



100 



50%. It is worthwhile to observe that in this type of a system the carrier 
cannot be suppressed without suppressing one of the channels at the 
same time. Thus, power is wasted in two ways: one is in the transmission 
of unutihzed cross-modulation power, which is larger than the low rate 
channel power, and the other is in the transmission of more than the 
required amount of unmodulated RF carrier power. These two sources 
of inefficiency are reduced by the Interplex modulation scheme. 

Two-Channel Interplex 

Let the phase-modulating signal be a linear combination of Si(t) and 
Si{t) S2{t). The transmitted signal is 

z{t) = \/2P sin [met + ^iSi(f) + 0,So4t)] (13) 

where 

Scmit) = Si(*) S^it) (14) 

is the cross-modulation signal. 

Again in Equation 4 the signal can be expanded trigonometrically into 
four terms; however, the second data channel will now be the cross- 
modulation term, while the new "cross modulation" will be 

S^{t)s„n{t) = Sl(t) S,{t) = S,{t) (15) 

since sj(*) = (±1)^ = 1. 

The result is that second data channel and the cross-modulation term 
are interchanged, while the first data channel and the RF component 
remain unchanged. Therefore 

Z{t) = [\/2F^ Si(*) + \/W7,n Scm(*)] COS (oe*) 

+ [V2P; -I- v^Prs2(f)] Sin («c*) (16) 



where now 



'Pi = P sin^ B^ cos= ^2 = Pi 



I P2 = P sin^ ^1 sin^ B^ = Pc, 
Interplex 7 ^ Conventional (17) 

I Pc = P cos^ ^1 cos= e^ = ?o 

,Pcm = F cos^ ^1 sin^ 62 = P2 



101 



TRANSMITTER 




V2P sin Tw^f + e (t)l 



RECEIVER 



m/v^' 














DEMODULATOR 
ASSEMBLY 


"V 


y 






' 






cos(cj t +<fi) 














vco 




FILTER 
































90° 











CHANNEL ] 




DEMODUWTOR 
ASSEMBLY 



CHANNEL 2 



Figure 2. Interplex two-channel system 

The only change relative to the conventional PSK/PM system is the 
use of a multiplier in the transmitter to form the product of the two 
binary signals Si{t) and S2(*). Since the result is also a binary signal, this 
requires only an exclusive or gate or a chopper, as shown in Figure 2. 
The receiver remains the same except that in addition to generating the 
coherent reference signal cos (act) its 90-deg phase shift sin {a>ct) is also 
required. In this system Si{t) is obtained as in the conventional scheme, 
but S2{t) is obtained by mixing z{t) with sin (uc*), as shown in Figure 2. 

The power in the cross-modulation component 



p - ^^^^ _ 

Pcm — p — aPc 



(18) 



is now directly proportional to Pc and thus there is no advantage in 
transmitting more RF power than needed for tracking. Also, Fcm < ^2 
while for the conventional scheme we had Fcm > P2. In fact, of the four 
components, the cross modulation has the smallest power. The total 

power is 



P = Px + P2 + Fo + -^ Po 

= (! + «) (P, + To) 



(19) 



102 



0.2 




INTERPLEX- 



^-P =0 

c 

P /P= 0.05 



7;„(MAX) 



CONVENTIONAL 



0.25 0.50 0.75 1.00 

= =P2/P, 

Figure 3. Data power efficiency of two-channel systems 

where 

a = -— = tan- 02 (20) 

Thus, the efficiency 

« = !- 



P.+Pc 

= sin- ^1 (21) 

can be made large for all choices of a simply by taking Pc to be a small 
fraction of Pi, which is usually the case in practical systems. Moreover, 
it is now advantageous to completely suppress the carrier (^i = 90 deg) 
and achieve 100% efficiency for all ratios a. This can actually be realized 
because methods for tracking the phase of a suppressed carrier are the- 
oretically feasible for the two-channel Interplex system (Reference 3). 

A graph of the efficiency of the two-channel Interplex system and the 
conventional system as a function of a is given in Figure 3 for several 
values of Pc/P. Note that except for very small a the carrier power allo- 
cated by optimizing the conventional system is more than the amount 
required by the phase-locked receiver. The improvement gained by the 
Interplex scheme approaches 3 dB for the equal power case (a = 1). 



103 



Multichannel Systems 

In an N-channel PSK/PM system, the phase-modulated RF signal is 
still the same form as Equation 1, and the conventional modulation 
is given in Equation 3. However, as suggested by the two-channel 
Interplex system, we can let 



®it) = 



+ 



7 ^ dn Sn{t) 



Slit) 



(22) 



Which of the two schemes is more efficient depends now on the power 
allocations required as well as on the number of channels. In general, 
Interplex is more efficient when N is not too large (N < 4 if the channels 
are equal, but larger values of N can be used when there is one high- 
power channel with many low-power channels). Two such cases are illus- 
trated in Figure 4. 

It is possible to show that no JV-term linear combination of products 
of signals yields a better efficiency than either Interplex or conventional 
systems (Reference 4). However, if more than N terms are allowed (ex- 
tended interplex) in a linear combination of signal products, then schemes 
are known (Reference 5) which outperform both the conventional and 
the simple interplex of Equation 22. 




0.4 



6 10' 2 

NUMBER OF CHANNELS N 



10 



Figure 4. Efficiency for N channels with Pt/P, = a, k = 2, • • ; N 



Conclusion 

This article has presented a multichannel PSK/PM modulation scheme 
called Interplex which reduces cross-modulation loss and excess carrier 
reference power of conventional systems when the number of channels 



104 



is small. In systems with equal channels, Interplex is more efficient when 
the number of channels is four or less. The number of channels which 
can be combined efficiently via Interplex increases if there are many low- 
power channels and only one high-power link, as is often the case in 
deep space telemetry. 

Although this article emphasized square-wave subcarriers, the basic 
ideas carry over when the subcarriers are sinusoids (Reference 6). The 
expressions for the various power terms will involve Bessel functions, 
and it is not difficult to show that Interplex offers significant improve- 
ment when N is small, as in the case of square-wave subcarriers. How- 
ever, the performance with sinusoids is inferior to systems with binary 
waveforms. 

Because of its promise of increased efficiency, further studies are being 
initiated to discover applicability to specific spacecraft missions. Experi- 
mental tests of the performance with simulated and actual ground and 
spacecraft telecommunications systems are also in progress. 



References 

1. Lindsey, W. C, "Design of Block-Coded Communication Systems," 
IEEE Trans. Communication Technology, Vol. COM-15, No. 4, 
Aug. 1967. 

2. Weber, L. C, "Theory and Design of Coherent Digital Systems which 
Track Doppler Frequency," Proc. IEEE, Vol. 58, No. 6, June 1970. 

3. Butman, S., and Timor, U., "Suppressed-Carrier Tracking for Two- 
Channel Phase Modulated Telemetry," Proceedings of the 'National 
Electronics Conference, Vol. 26, Dec. 1970. 

4. Timor, U., "Optimum Configurations for PSK/PM Systems," in 
Supporting Research and Advanced Development, Space Programs 
Summary 37-66, Vol. Ill, pp. 33-36. Jet Propulsion Laboratory, 
Pasadena, Calif., Dec. 31, 1970. 

5. Tausworthe, R. C, "A Boolean-Function Multiplexed Telemetry Sys- 
tem," IEEE Trans. Space Electronics Telemetry, Vol. SET-9, No. 2, 
pp. 42-45, June 1963. 

6. LaFrieda, J., "Space Station Unified Communication: Optimum Per- 
formance of Two-Channel High-Rate Interplex Systems," in Support- 
ing Research and Advanced Development, Space Programs Summary 
37-65, Vol. Ill, pp. 31-36. Jet Propulsion Laboratory, Pasadena, Calif., 
Oct. 31, 1970. 



105 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Calculation of Space-Charge Forces in the Analysis 
of Traveling-Wave Tubes 

H. K. Detweiler 
Telecommunications Division 



A comprehensive large-signal traveling-vv^ave tube computer program has 
been developed for the study and design optimization of high-efficiency 
space-type tubes. Studies have been made previously with a theory which 
employs a "deformable-disk model" (DDM) for the electron beam, but 
neglects RF space-charge forces in the beam. That theory was found to 
yield accurate predictions for tubes in which RF space-charge forces are 
not the predominant factor in determining device performance. However, 
RF space-charge effects can be very important in tubes designed for space 
flight applications. Thus, it is essential to include them in the computer 
calculations if accurate predictions of device performance are to be ob- 
tained. Expressions for the space-charge fields, appropriate to the DDM 
representation of the electron beam, are presented in this article and the 
methods used in the calculations are described. 



Introduction 

A comprehensive large-signal traveling-wave tube (TWT) computer 
■program has been developed for the study and design optimization of high- 
efficiency space-type tubes. This program allows for a consideration of 
the various magnetic focusing means which are commonly employed to 
minimize weight and has provisions for determining the efficacy of the 
phase-focusing techniques used to improve efficiency. 

A typical TWT configuration is schematically illustrated in Figure 1. 
In essence, this device consists of an electron gun, an RF circuit capable 
of supporting the propagation of a slow electromagnetic wave having a 
longitudinal electric field component, and an electron collector. Electrons 
are emitted from the cathode and focused into a beam in the gun region 
such that their motion is predominantly parallel to the axis of the slow- 
wave circuit. They next traverse the circuit region where an interaction 
takes place with the RF wave propagating on the circuit. Subsequently, 
the electrons enter the collector and are removed from the device. When 



106 




Figure 1. Schematic illustration of a traveling-wave tube 

conditions are proper, the beam-wave interaction which occurs in the 
circuit region results in a net transfer of energy from the beam to the 
wave with resultant amplification of the RF signal. The increase in power 
carried by the circuit wave comes about as a result of a conversion of 
the kinetic energy of electrons in the beam. The radial circuit fields and 
space-charge (Coulomb) fields cause a radial perturbation of the electron 
trajectories during the interaction. A magnetic field is usually employed 
to constrain the electron beam as it passes through the circuit region; it 
may be a uniform axially directed field or spatially varying (e.g., peri- 
odic) field. 

The performance of TWTs can be evaluated by using a nonlinear 
Lagrangian analysis in which the electron beam is -subdivided into indi- 
vidual charge groups that are tracked through the interaction region. 
Early analyses employed a rigid-disk model for the electron beam (Ref- 
erence 1). In that model, the beam is divided axially into a number of 
constant diameter disks of charge as illustrated in Figure 2a. The effects 
of radial motion of the beam electrons cannot be evaluated with such a 
model. Later studies (References 1 and 2) made use of a ring model in 
which the beam is further subdivided radially into concentric rings of 
charge as shown in Figure 2b. These rings were permitted to change 
diameter according to the radial forces acting upon them, thus account- 
ing for the effects of radial variations. While accurate predictions of 
TWT performance were obtained, solutions were found to be quite costly 
because of the large number of charge groups required in the computer 
simulation. A disk model permits the use of fewer charge groups, but 
the modeling must be such that radial motion of the electrons and radial 
field variations, which have important effects in space-type TWTs, are 
taken into account. The "deformable-disk model" (DDM) illustrated in 
Figure 2c satisfies these requirements (Reference 2). 

In the DDM representation of the electron beam, the disks are allowed 
to vary in diameter in response to the radial fields acting upon them. 
The radial motion of electrons contained within a disk is described 



107 




(c) DEFORMABLE-DISK MODEL 



Figure 2. Electron beam models 



according to laminar-flow theory. The axial motion of a disk is obtained 
by averaging the forces across its diameter. 

Solutions to a set of nonlinear interaction equations based on the DDM 
representation of the electron beam, but neglecting the RF space-charge 
forces which result from the Coulomb interaction of the beam electrons, 
have been presented previously (References 2 and 3). The results show 
that accurate predictions are obtained for tubes in which RF space- 
charge forces are not the predominant factor in determining device per- 
formance. However, RF space-charge effects can be very important in 
the light-weight, high-efficiency traveling-wave tubes designed for space 
flight applications. Thus, it has been necessary to include them in the 



108 



computer calculations. Expressions for the space-charge fields, appro- 
priate to the DDM representation of the electron beam, are presented 
in this article and the methods used in the calculations are described. 



Expressions for the Space-Charge Fields 

Explicit expressions for the space-charge fields may be obtained 
through the solution of Poisson's equation within the interaction region 
by using Green's function techniques. Rowe (Reference 1, pp. 95-97) 
has carried out this procedure for a ring model of the electron beam by 
finding the space-charge potential determined from the Green's function 
for a delta-function ring of charge located in a perfectly conducting 
drift tube. He then found expressions for the radial and axial space- 
charge fields by differentiating this space-charge potential function. 
Utilizing Rowe's results, the space-charge fields for the DDM represen- 
tation of the electron beam are obtained in the following manner. The 
laminar-flow assumption is invoked, which permits a radial integration 
over all the rings of charge located at a given axial displacement plane 
to be performed in the ring-model space-charge-field expressions. Eval- 
uation of the resulting equations for the radius of a disk yields the space- 
charge-field components at that point. The radial field component is used 
directly; the axial field component is averaged over the cross section 
of the disk. 



The resulting expressions for the radial and axial space-charge-field 
components for the DDM representation of the electron beam are 



-C^o>\L 



^"-' (''' *) " U^^€oX- ' ^'-' ^''' '^' *' *'^ "^^'^ ^^^ 



a Jo 



and 



Ese-. (x, $) = ^2^^^^, j F,_, (x, X', #, $') sgn ($ - $') d¥^ 



1^ Jo 



(2) 



where 



1, for # > #' 
0, for «> = #' 
- 1, for $ < $' 



sgn (# - *') = ^ 0, for # = #' 



109 



Table 1. Definition of symbols 



a mean radius of the circuit, m 

C gain parameter defined by C = Zo\h\ /4Vo 

E,c-r, E,c-s radial and axial components of the space-charge field acting on a 
disk of normalized radius x and phase cj>, V/m 

Fz-r, F2-J radial- and axial-component space-charge weighting functions de- 
fined by Equations 3 and 4, respectively 

L dc beam current, A 

/o (to) zero-order Bessel function of the first kind of argument w 

}i (w) first-order Bessel function of the first kind of argument ic 

m number of representative charge disks injected into the interaction 
region during one cycle of the RF wave 

r radial-position variable, m 

«o average initial axial-velocity component of electrons in the beam, 
m/s 

Vo dc beam voltage, i.e., the dc voltage on the beam axis, V 

X normalized radius of a disk, ( Ca/uo ) r 

Xa normalized mean circuit radius, (Cw/Uo) a 

Zo characteristic impedance of the RF circuit (evaluated at the circuit 
radius ) at the frequency of the wave, i2 

z axial-distance variable, m 

e permittivity of free space, F/m 

VI roots of /o ( Vi Xa ) =0 

# phase position of an electron disk relative to the RF wave, rad 
e!>^ entrance phase of an electron disk, rad 
CO radian frequency of the RF wave, rad/s 

The functions 'F.^-r and Fg-- are the space-charge weighting functions 

which are given by 



and 



-"* /_^ 



_^—^ exp [-v^C|*-*'|] (4) 

fci v|xx' [A {yiXo)V 

where vi is determined from the successive zeros of /o(viXo), i.e., 
laiyix^ = 0. The remaining quantities introduced in the above equa- 
tions are defined in Table 1. 



110 



The space-charge weighting functions given by Equations 3 and 4 
indicate the influence of a source disk of radius %' and phase $' on the 
observed disk of radius x and phase $. The space-charge-field compo- 
nents at the position of the observed disk are then evaluated by inte- 
grating over all the source disks as done in Equations 1 and 2. The 
radial and axial space-charge forces on the observed disk are propor- 
tional to the field components determined from these equations. This 
procedure can be carried out in a straightforward manner during the 
computer solution of the interaction equations once the radius and phase 
of all charge disks are known. However, the weighting functions must be 
evaluated many times (considering the radial and axial force on each 
disk due to all the disks) at each of several hundred axial displacement 
planes. Repeatedly evaluating them directly from Equations 3 and 4, 
using the actual radius and phase of each disk, would result in prohib- 
itively long and costly computing times. Following the procedure sug- 
gested by Rowe (Reference 1) of using weighting-function tables reduces 
the computing time per solution appreciably and does not significantly 
affect the accuracy of the results. 

Weighting-Function Tables 

This procedure involves dividing the cross section of the interaction 
space into a number of annular regions (the innermost region is, of 
course, circular rather than annular). The weighting functions are calcu- 
lated for specified values of j # — <&' | at radii corresponding to the mid- 
radius of each of these regions and then stored in tabular form in the 
computer memory. This information is used by the large-signal TWT 
program to evaluate the weighting functions in the manner described 
below, thus avoiding the need to calculate them directly so many times. 

Several computer programs, separate from the DDM large-signal TWT 
computer program, are used to generate the weighting functions. These 
are used sequentially to calculate the "raw" weighting functions corre- 
sponding to the mid-radii of the space-charge regions directly from 
Equations 3 and 4 and then to truncate these weighting functions accord- 
ing to the procedure described later. The results are punched on cards 
which are subsequently read into the computer memory when calcula- 
tions are to be made with the large-signal program. These data are in the 
form of tables of Fa-^ and F.,-~ for specified values of | <E> — #' |, each table 
corresponding to a single value of (x, x'). In the main program, the com- 
puter is instructed to scan all of the tables when particular values of 
X, x', $, and *' are given, select those tables (one each for F^-^r and ¥.,-.^ 
corresponding to the regions within which x and x' are located, and cal- 
culate the appropriate weighting functions by interpolating (over # — #') 
between the tabulated values. 

It is obvious that this procedure does not yield the space-charge forces 
corresponding to the actual disk positions, but gives instead those forces 



111 



which would exist if each disk had a radius equal to the mid-radius of 
the space-charge region in which it is located. However, the resultant 
errors which are introduced into the calculations are not serious when a 
sufficient number of space-charge regions are used. This method permits 
a considerable reduction in computing time, which is necessary from a 
practical standpoint, and has given results in good agreement with ex- 
perimental data. If an improvement in accuracy is desired, or required, it 
can be obtained by subdividing the interaction space into a larger num- 
ber of space-charge regions. 

Figure 3 illustrates the radial subdivision of the interaction space into 
seven regions, which is sufficient for most traveling-wave tubes. The 
values of x and x' for which the weighting functions are computed and 
stored are indicated in this figure, as are the radii of the space-charge- 
region boundaries. As mentioned previously, when looking up the 
weighting functions from the tables, the radius of each disk is assumed 
to be equal to one of these indicated values of x (or x'), regardless of its 
actual location within the particular region. When a disk radius crosses 
a region boundary, it is then assumed to be equal to the value of x (or 
x') for the region it has entered. 

For the seven regions used in this model, there are a total of 98 
weighting-function tables. Each table consists of the values of a weight- 
ing function corresponding to a single value of (x, x') at 29 distinct values 
of I $ — #' j which span a -n range in phase. (The spacing of the | $ — <&' | 
values was chosen as 7r/160 for the range to tt/S, tt/IQ for tt/S to -n/l, 
and 7r/4 for -it/2 to it.) Since the weighting functions are even functions 
of # — $', it is only necessary to calculate and store them over a to tt 
range of <l> — $' values. 



RAOli OF 
REGION VALUES OF 
BOUNDARIES x OR x' 





-'3xyi4 


a/ 


^ @ -11V14 


4x /7 


^ _ 9x^,4 


=1/ 


^ ^ ,^/2 


a/ 


^ ^ 5,^/,4 


Q 


^ ^3x^14 


a/ 


^xyu 



Figure 3. Division of interaction space into seven annular regions 
for computation of space-charge weighting functions 



112 



2.4 




Figure 4. Radial space-charge weighting functions with 
xo/C = 1.5, X = xa/2, x' = variable 




0.4 



Figure 5. Axial space-charge weighting functions with 
xo/C = 1.5, X = x„/2, x' = variable 



Representative radial and axial weighting functions calculated for the 
seven-region model using Equations 3 and 4 with xJC = 1.5 are shown 
by the solid curves in Figures 4 and 5. The individual weighting func- 
tions are designated by an ordered pair of numbers which correspond to 
the numbered space-charge regions that they represent. The first number 



113 



in a pair refers to the region in which the radius of the observed electron 
disk is located, while the second refers to that in which the radius of the 
source electron disk is located. The short-range nature of the space- 
charge forces is clearly indicated by these plots. As can be seen, the 
weighting functions are quite small at | * — *' I = 7r/2. They continue 
to decrease for larger phase separations and are negligibly small for 
I # — #' I ^ IT. It is this property which allows the space-charge fields 
to be evaluated by integrating only over a 27r phase range as done in 
Equations 1 and 2. 

The space-charge fields calculated using the "raw" weighting functions 
directly are those arising from a continuous distribution of elementary 
charge elements, i.e., infinitesimally thin disks of charge. The discrete 
charge disks used in the Lagrangian analysis of the nonlinear interaction 
problem actually represent numerous electrons distributed over a finite 
volume and thus they have a finite size. The space-charge forces between 
these representative charge disks differ somewhat from those calculated 
on the basis of thin disks. However, the difference is significant only 
when the separation between representative charge disks becomes small 
enough that they, in effect, overlap. This can be taken into account 
approximately by truncating the weighting functions appropriately. 

The method used for the axial weighting functions is to truncate 
them linearly to zero at $ — $' = from their respective values at 
I $ — $' j = 27r/m, where m is the number of representative charge disks 
injected into the interaction region during one cycle of the RF wave. 
This results in a linear decrease in the axial space-charge force between 
two charge disks when their phase separation decreases below the initial 
disk spacing (which is also their effective initial phase width). 

The radial weighting functions for x = x' are linearly truncated from 
their respective values at |# — $'| = 2iT/m to average values at 
# — #' = assigned according to 

F,_, X = x') U-*'=o = -p^ > ^— 1 - exp f - V,-— 1 

(5) 

This equation was derived by computing the unweighted average of 
Fs-r for X = x' over the $ — #' interval from —ir/m to Tr/m. 

The truncated weighting functions depend upon the number of charge 
disks per cycle of the RF wave (m) used when making the large-signal 
calculations. The truncations for m = 32 are indicated by the dashed 
lines in Figures 4 and 5. Although these truncation procedures certainly 
do not make the space-charge calculations exact, they do approximately 



114 



account for the fact that the representative charge disks are not thin 
disks, but instead represent a finite amount of charge distributed over 
a finite volume. The accuracy improves as more representative charge 
disks per cycle are used because they become more like the elementary 
charge elements for which the fields are derived and the region over 
which the weighting functions must be truncated is reduced. H[owever, 
some sacrifice in accuracy must be accepted in order to limit the cost 
of the computations since the computing time increases roughly as the 
square of the number of charge disks employed. 

Results 

The accuracy of the space-charge calculations can be checked by com- 
paring the radial forces for an unmodulated beam in Brillouin flow 
obtained using the weighting functions to those calculated from Gauss's 
law. One such calculation performed for a beam whose radius was one- 
half that of the circuit yielded a value of the radial space-charge force 
which differed from the Gauss's law value by only 1%. A computer run 
made with the DDM program for this case showed that the beam was 
perturbed by the amount expected from theoretical considerations for a 
1% error in the radial space-charge force. 

A number of solutions have been obtained using the DDM large-signal 
TWT computer program, including RF space-charge forces, for device 
parameters investigated previously with the TWT theory based on a ring 
model for the beam, a theory for which experimental verification has 
been obtained (Reference 2). The results were found to be in good agree- 
ment, indicating that the deformable-disk model is an adequate repre- 
sentation of the electron beam and that no significant errors are made in 
the space-charge-force calculations described here. Of particular signifi- 
cance is that the cost per solution using the DDM program is only about 
one-tenth of that required for the ring-model program. 



References 

1. Rowe, J. E., Nonlinear Electron-Wave Interaction Phenomena. 
Academic Press, Inc., New York, 1965. 

2. Detweiler, H. K., Characteristics of Magnetically Focused Large-Signal 
Traveling-Wave Amplifiers, Technical Report 108. Electron Physics 
Laboratory, The University of Michigan, Ann Arbor, Oct. 1968. 

3. Detweiler, H. K., and Rowe, J. E., "Electron Dynamics and Energy 
Conversion in O-Type Linear-Beam Devices," in Advances in Micro- 
waves, Vol. VI. Academic Press, Inc., New York (to be published). 



115 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



A Magnetic Tape Recorder for Long 
Operating Life in Space 

E. Bahm 



Astrionics Division 



In the past, magnetic tape recorders for space applications have caused 
many problems. However, they are still widely used because they are the 
only mass memory device acceptable for spacecraft. Most of the tape recorder 
problems have been associated with the mechanical tape transport, while the 
tape recorder electronics generally achieved a satisfactory performance 
record. This article describes a tape recorder which uses a very simple me- 
chanical system to transport the tape with very few possible failure modes. 
The simplicity of the tape transport has been achieved at the expense of 
added complexity of the electronic system. The resulting tape recorder is 
better balanced in its mechanical and electronic reliability. The test results 
with a feasibility model have been very encouraging. 



Introduction 

Outer-planet spacecraft design studies have established the need for 
large capacity data storage systems with a lifetime of up to 12 yr. An 
extensive survey of all available mass storage techniques has shown that 
magnetic tape recording has the highest probability of meeting the 
requirements of outer-planet missions until 1980. However, spacecraft 
and satellite tape recorders in the past have achieved a less than satisfac- 
tory performance record in spite of considerable efforts in research and 
development. Even though JPL has never had an inflight tape recorder 
failure, doubts have been expressed whether the magnetic tape recorder 
can ever be perfected enough to meet projected outer-planet reliability 
and life requirements. 

A study of tape recorder failure modes in the past revealed that 
failures within the mechanical transport package outnumbered failures 
within the electronic system. However, it was not possible to identify 
a single part or subassembly within the transport package as being par- 
ticularly failure prone. The presently used tape transports, therefore, 



116 



must be regarded as particularly suspect systems having the potential 
for many different failure modes. 

A study of tape transports which have flown on spacecraft and satel- 
lites in the past shows that they were all complex devices with many 
moving parts. The reason for the complexity of the mechanical system 
is found in the peculiar functional and environmental requirements 
placed on space-borne data storage systems. One of the requirements 
most difficult to achieve with a tape recorder is the multiple-data rate. 
For certain appHcations in the past, data rates differed by a ratio of 
nearly 1:2000, which means that the highest tape speed had to be 2000' 
times faster than the lowest tape speed. 

Several years ago JPL recognized the need for less complicated tape 
transports and directed a strong effort toward the development of simple, 
reliable tape transports. The first of these transports uses the peripheral 
drive principle and will be flown for the first time in 1971 on board 
the Mariner spacecraft. This machine has achieved satisfactory test 
results, and the confidence is high for it to set new standards for tape 
recorder life and reliability. However, the peripheral drive tape recorder 
is only one step toward the development of a truly reliable recorder, 
which vvdll completely satisfy outer-planetary spacecraft requirements 
until 1985. Several more steps toward achieving this ultimate goal are 
already taking shape in the laboratory. 

This article describes a data storage system utilizing a simple tape 
transport, of which a feasibility model has already been built. This 
transport uses only two rotating assemblies. None of the rotating assem- 
blies operate at high speed. Besides the magnetic tape and the two 
rotating assemblies, there are no other moving parts, such as drive belts 
or spring tension devices. Most important, however, is the fact that this 
transport, due to its simplicity, is expected to have very few possible 
failure modes, and even those should occur with a low probability. The 
mechanical simplicity is achieved partly by unorthodox methods of driv- 
ing and tensioning the tape and partly by elimination of the naulti-speed 
requirement from the tape recorder while retaining it for the data storage 
system as a whole. 

The data storage system uses a pair of solid-state buffer memories 
for data rate conversion. It allows the tape recorder itself to operate at 
a single data rate which can be selected to be compatible with the tape 
transport. As a consequence, the mechanical subsystem has been simpli- 
fied and made more reliable at the expense of additional electronics. The 
advantages gained for the transport will outweigh the disadvantages 
caused by the introduction of additional electronics. If redundancy is 
used for certain circuits, such as the buffer memory, it will be possible 



117 



to further increase reliability of the data storage system. Present plans 
call for this tape recorder to be used for outer-planet missions. 



Data Storage System Design 

The data storage system will be able to store and reproduce a large 
amount of digital data at a variety of data rates. Figure 1 shows the 
data storage system in block diagram form. It uses a single-speed tape 
recorder and two identical serial buffer memories. The tape recorder 
communicates only with the buffer memories at a constant data rate, 
while the buffers communicate with the other subsystems at any data rate 
up to a certain limit R. 

During recording, data is first stored in Buffer A, while Buffer B 
transfers its contents to the tape recorder at a sufficiently high data rate 
to assure the data transfer to be finished before Buffer A is filled to 
capacity. The tape recorder is subsequently stopped until Buffer A is 
full. Then the function of the two buffers is reversed, and Buffer A 
transfers its contents to the tape recorder while Buffer B is recording 
the incoming data stream. This allows the recording of a continuous data 
stream with a tape recorder operating in a start/stop mode. The switches 
indicated in Figure 1 represent logic circuits capable of properly direc- 
ting the data streams and starting and stopping the tape recorder. This 
data storage system is described in detail in Reference 1. 

The buffer memory can be a long shift register or any other semi- 
conductor, core, or plated wire memory. The buffer capacity determines 
the length of a data block written on the magnetic tape. The tape re- 
corder stops and restarts between successive data blocks during which 
time the tape moves at a variable speed, and no data can be recorded. 
This results in a gap between data blocks. The gap length is strictly a 
tape transport characteristic and depends upon tape speed, start time, 
and stop time of the transport. It is, therefore, desirable to design the 
tape recorder for generating short gaps. It is also desirable to use buffers 
with sufficient storage capacity to yield data blocks which are long com- 
pared to the gap length in order to achieve good tape utilization. 

For the tape jecorder described in this article, the gap length is 
approximately 1.27 cm (0.5 in.)^ at a tape speed of 17.78 cm/s (7 in./s). 
If a linear recording density of 1575 bits/cm (4000 bits/in.) and single 
track recording is assumed, a pair of 8096-bit buffers would generate 
data blocks of 5.08 cm (2 in.). This would result in 80% of the magnetic 
tape being used for data recording. 



iWhere applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents 
the nieasured or calculated unit. 



118 





|— 


BUFFER A 


h 






DATA INPUT 
AMD o— 


-^ 






TAPE 
RECORDER 


OUTPUT 


/ ^ 


/ 




BUFFER B 


— 


/ 




/ 


/ 

— DATA RATE 

0—R 

(VARIABLE) 






^ DATA RATE >R 
(CONSTANT) 



Figure 1. Data storage system 

Tape Transport 

The most important design requirements for the tape transport are high 
reliabihty and long life. This implies that a transport can never employ 
components that are basically unreliable or subject to considerable wear. 
Any mechanical system, however, must be satisfied with components 
having at least some wear and limited reliability. It is concluded, there- 
fore, that all components and materials which are subject to wear, fatigue, 
or chemical instability should be known to function for 12 yr with some 
acceptable probability of success. Furthermore, their number should 
be reduced to the bare minimum. 

From these rather general design rules, a number of more specific 
postulates can be derived: 

(1) The transport mechanism shall be as simple as possible. It shall 
be stripped of all non-essential functions or components. 

(2) Since there is no known way to construct a tape transport without 
bearings (which are subject to wear and fatigue), their number 
shall be minimized, and they shall be selected for minimum wear 
and fatigue. Ball bearings are generally considered most desirable 
for tape recorders. Their wear can be reduced to negligible values 
if operated at very low speed and load and assured lubrication. 
Material fatigue is also negligible if they are sufficiently oversized. 
Proper lubrication can be assured for long periods by using 
grease instead of oil. Again, large bearings will hold larger quan- 
tities of lubricant, and slow speed will stretch out the aging 
process of the lubricant. 

(3) A tachometer is not an essential component and shall not be used. 
Playback of a prerecorded control frequency on the tape will more 
reliably generate a speed signal. 

(4) Drive belts commonly used in tape transports can fatigue and 
break. There is not enough data available today to assure that 
l?;;lts can maintain the necessary tension over a period of 12 yr. 
Drive belts, therefore, shall not be used. 



119 



(5) The oxide surface of the magnetic tape should not be in sUding 
contact with any sohd surface to minimize tape -wear. If this is 
not possible, the total surface area sliding against the oxide and 
the contact pressures involved shall be minimized. 

( 6 ) Magnetic tape shall be handled as gently as possible. It, therefore, 
shall be guided along as few devices as possible and it shall not 
be wound tightly on a reel. 

(7) The number of non-metallic substances shall be minimized and 
the chemical stability and compatibility of all materials inside the 
transport package shall be carefully verified. 

(8) The number of connector pins feeding through the transport 
package shall be minimized because connector feedthroughs pre- 
sent a sealing hazard. This suggests incorporating part of the 
electronics inside the transport package, especially for multi- 
channel recorders. All electronic components inside the transport 
shall be enclosed in hermetically sealed metal containers to pre- 
vent contamination of the transport by outgassing products from 
electronic components. 

In order to satisfy Postulates 1 and 6, a coplanar reel-to-reel transport 
configuration is most promising. Figure 2 shows a very simple configura- 
tion. It consists of two motors with reels and tape packs on each motor 
shaft. It also uses two stationary tape guides, which do not touch the 
oxide, and a set of recording heads. All components are mounted on a 
precision plate. 

The magnetic tape is fastened to the reel hubs. The take-up reel 
motor pulls the tape and winds it on its reel. The supply-reel motor 




-HEAD STACK 
-TAPE GUIDE 



TAPE 
PACK 



REEL AND MOTOR 



Figure 2. Two-motor tape transport 



120 



50 - 



40 



20 - 



10 - 



1 


1 1 1 1 
ACTUAL DC MOTOR 


- \^ 


CHARACTERISTIC _ 


\^ 


,0 ^^ DESIRED MOTOR CHARACTERISTIC - 


' \ 




A. 


_ o 


Vs. 


z 


\\^ 


< 


Y\ioo 


Q^ 




o 

z 


30.5 \/\ 


\ V°° V TAPE 


< 


V\ ^\ LENGTH, feet - 


Q_ 


6I.0\\. 300 ^^^ 


o 








meters oi ^\\ ^"^ 

^V 500 






121.9 >5~J 600 


=__!_ . 






~ I5I4 \182.9 


ASSUMPTIONS 


\ 


TAPE SPEED: 


10.2cm/s(4 in./s) 


TAPE TENSION 


0.3 kg - 


MAX TAPE PACK DIAM: 10.2 cm (4 in.) 


MIN TAPE PACK DIAM; 3.8 cm (1.5 in.) 


TAPE LENGTH: 


182.9 m (600 ft) 
1 1 1 1 



3 0.6 0.9 1.2 

TORQUE, kg-cm 

Figure 3. Take-up reel drive 



develops torque in the direction opposite to the tape motion. It, therefore, 
pulls back on the tape, generating tape tension. While the take-up reel 
motor generates tape speed, the supply-reel motor provides for the nec- 
essary tape tension. The transport is symmetrical and, therefore, can 
drive the tape in both directions equally vi^ell. Tape speed reversal is 
obtained by interchanging the functions of the two motors. 

During normal operation the tape speed has to be precisely constant. 
Since the tape pack diameter on the take-up reel changes constantly, 
the take-up motor speed will change throughout a tape pass. At the 
beginning of a tape pass, the tape pack is small and motor speed has 
to be high. For the same reason, motor torque is low if constant tape 
tension is assumed. As more tape is wound on the reel, motor speed will 
decrease and torque increase. Figure 3 shows the desired motor speed 
as a function of motor torque at constant tape tension. This hyperbolic 
function can be nicely approximated by the proper design of a dc motor 
and fine trimming with a series resistor to the motor. The take-up reel 
motor therefore will automatically generate approximately constant tape 
speed if constant tape tension is provided. Conversely, if the tape speed 
is held constant, tape tension will deviate from the nominal values only 
by a small amount. 



121 



MAGNETIC TAPE 




CONSTANT 
REFERENCE 
FREQUENCY 



Figure 4. Drive electronics for two-motor tape transport 

The supply motor generates tape tension and is being servo-controlled 
to regulate the tape tension in such a way that constant tape speed 
results. This is being done with a phase-lock servo, which compares a 
voltage derived from the tape with the voltage output of a stable oscil- 
lator. The tape signal is pre-recorded on a precision laboratory recorder 
on one track over the full length of tape. The tape recorder itself has only 
playback capability on this track. The frequency derived from this track 
is directly proportional to the tape speed. 

The phase-lock servo has two feedback loops, as shown in Figure 4. 
One loop generates an error signal proportional to the difference of the 
frequencies of the two voltages. This error signal is filtered and amplified 
and will subsequently be used to drive the supply motor. It wiU regulate 
motor current in such a manner as to cause the tape frequency to become 
approximately equal to the stable reference frequency. A second feedback 
loop will generate an error signal proportional to the phase difference 
between the two voltages. Its error signal will take over the job of regu- 
lating the motor current after the first loop has brought the tape fre- 
quency within capture range of the second loop. 

This double-loop servo will feed just enough electrical power into the 
supply motor to cause tape speed to be precisely constant at all times. 
The speed is determined by the external reference frequency and the 
density at which the tape frequency has been recorded. 

A very important feature of this tape transport is the fact that the tape 
tension will disappear as soon as the recorder is turned off. This is very 
desirable because it vsdll prevent tape-to-head stiction during prolonged 
periods of inoperativeness. However, the tape has to be prevented from 
falling off the tape guides or throwing a loop. For this purpose, the tape 
reels contain flanges which are more precise than for most other tape 
recorders. The tape is allowed to fall down on the flanges after the 
recorder has been turned off. Throwing a loop is prevented by using a 



122 



magnetic brake in each motor. The motors, always running at slow speed, 
will be stopped by the brake in a very short time. 

The brake consists of a powerful permanent magnet and a weak per- 
manent magnet which is magnetized by the powerful magnet. As one 
magnet rotates and the other remains stationary, the weak magnet is 
continually re-magnetized by the powerful magnet. This causes high 
hysteresis losses because the coercivity is not negligible. These losses 
result in a drag torque which opposes the rotation and can be made 
constant in the time and speed domain. Past experience indicates the 
required brake torque will be on the order of 0.07 to 0.36 kg-cm 
(1 to 5 oz-in.), depending upon the reel diameter. In a practical motor, 
the powerful magnet is identical with the dc motor magnet and the weak 
magnet takes the place of the soft iron yoke ring. Therefore, the braking 
action is obtained by simply selecting a proper magnetic material for 
the yoke ring. No geometric changes of the motor design are required. 

In order to obtain good damping characteristics, the motor is designed 
with relatively high brake torque. This generates more tape tension than 
desired. The brake torque of the supply motor must therefore be reduced 
by driving the motor in the direction of the tape travel with very little 
torque. Referring again to Figure 4, the double-loop servo generates an 
error signal that is amplified to drive the supply motor. The servo ampli- 
fier is biased so as to drive the supply motor with low torque in the 
direction of tape travel if the error signal is zero. If the tachometer fre- 
quency begins to fall below the stable reference frequency, a positive 
error signal is generated and drives the supply motor with more torque. 
As the supply motor generates more torque against the brake, the pull 
on the tape will be relaxed somewhat, which allows the free running 
take-up motor to accelerate and increase the tachometer frequency. Tape 
speed is thus stabilized by regulating the net shaft torque of the braked 
supply motor. 

As mentioned before, the tape transport will be operated in a start/stop 
mode. Because both motors run at very slow speeds and exhibit a sub- 
stantial drag torque, the tape transport stops very fast. It also starts very 
fast because of the high starting torque of the dc motor. 

The general reliability and operating life of an incrementally operated 
tape transport is often questioned. Increased wear of bearings, tape, and 
heads is claimed. This may be true to some degree. Several years ago, 
JPL developed an incremental tape recorder (Reference 2) which was 
subjected to extensive life testing at high repetition rates. This machine 
accumulated approximately lO** start/stop cycles before it was finally put 
in storage. No bearing, head, or tape load was ever exchanged. This test 



123 



did not preclude the possibility of accelerated wear within an incre- 
mentally operated tape transport, but showed that a properly designed 
machine can perform a large number of start/stop cycles. 

The motors of the tape transport of Figure 2 run in the vicinity of 100 
rev/min for a typical space application. If operated continuously for 1 
yr at 100 rev/min, a bearing will accumulate approximately 50 million 
revolutions. With proper lubrication this will not wear out an originally 
healthy bearing. It is not clear, however, if proper lubrication is assured 
during a stop/start transition. Some degradation of the lubricating 
process must be assumed. Measurements of electrical current conduc- 
tivity between inner and outer race ways of ball bearings indicate that 
some separation of the metallic surfaces is accomplished even when the 
bearing is stopped. This leads to the conclusion that at least some lubrica- 
tion occurs all through the stop/start cycle. 

Concluding Remarks 

The tape recorder described in this article is currently being developed 
for future outer-planet missions. A feasibility model has been built and 
operated successfully for more than 1000 h without failure. 



References 

1. Slaughter, D. W., "A Multi-Instrument Data Conditioning, Storage 
and Retrieval System for Planetary Spacecraft," in Supporting Re- 
search and Advanced Development, Space Programs Summary 37-27, 
Vol. IV, pp. 101-107. Jet Propulsion Laboratory, Pasadena, Calif., 

June 30, 1964. 

2. Bahm, E., "Tape Recorder With Incremental Playback Capabilities," 
in Supporting Research and Advanced Development, Space Programs 
Summary 37-40, Vol. IV, pp. 170-174. Jet Propulsion Laboratory, 
Pasadena, Calif., Aug. 31, 1966. 



124 



JPL Quarterly Technical Review Volume 1, Number 1 April 1971 



Lunar Traverse Missions 

R. G. Brereton and J. D. Burke 
Advanced Technical Studies Office 

R. B. Coryell 

Project Engineering Division 

L D. Jaffe 
Space Sciences Division 



The results of recent JPL studies on Lunar Traverse Missions are com- 
pared with the announced characteristics of the Soviet Lunokhod 1 rover, 
delivered to the Moon by the L-una 17 spacecraft in November 1970. Except 
for some differences in emphasis among the scientific experiments, the 
Lunokhod mission is quite similar to those recommended in the JPL studies. 



Introduction 

It has long been recognized (References 1-3) that mobility is essential 
for exploring lunar and planetary surfaces. For the past several years, 
scientists and engineers at JPL have been working on various aspects 
(References 4-15) of lunar and planetary roving missions to prepare 
for the time when it would be possible to carry instrument payloads on 
mobile vehicles controlled from Earth. When the Soviet spacecraft 
Luna 17 delivered an automated rover, Lunokhod 1 (Figures 1, 2, and 3), 
to the Moon, this prospect became a reality. In this article, we compare 
the results of our studies with the announced data (References 16 and 
17) on the Lunokhod mission, whose main objectives appear to be almost 
exactly those recommended for an early mission by the JPL study teams. 



125 



^ 




* 







i 



.m-st- 



m' 






^r 






riiii n 



% 



r 













-^fer;?k'**^*- 



iSih- 



*s...^ 




.-.?«% 



Figure 1. Soviet Moon Car Lunokhod 1 in testing-assembling building prior to flight of Luna 17. Two TV cameras are 
at front; dark cylindrical objects at sides are telephotometer (facsimile) cameras, two scanning in vertical plane and 
two scanning slightly below horizontal (photo credit: TASS from SOVFOTO) 



Figure 2. Working parts of Lunokhod 1 pictured during test at Lunodrome 
(photo credit: TASS from SOVFOTO) 



127 



■" I 












if-C"- s. 



























,-- ', -^ ,--» , <w* 

r- .-~'V~-. ^v -r^ -"■■' - -< 






-J 









'-^ ' .;- 'V .- ' !.- -^ 5» '-t '\- - , .-; '..?, i 'I 

Figure 3. image of lunar surface from Lunokhod telephotometer 
(facsimile) camera showing one wheel and tracks left by vehicle 

(photo from Prawda) 



128 



Lunar Scientific Objectives 

The major goal of lunar scientific exploration remains to determine the 
origin and history of the Moon and its implications for the origin and 
history of the Earth and the solar system. In the JPL studies, the follow- 
ing major questions, whose answers would meet this goal, were posed: 

(1) Initial source of bulk lunar material: 

^a) Where was its location in the circumsolar cloud? 

(b) What was its pre-accretion chemical evolution? 

Mode of accumulation of the Moon: 



(2) 



(3) 



The 



a) Did it accumulate by independent accretion or by derivation 
from the Earth? 

b) What was the time of accumulation, i.e., the elapsed time 
since the effective cessation of nucleosynthesis? 

c ) What was the duration of accumulation? 
Post-accretion lunar history: 

a ) What are the major Moon-wide geological processes and their 
energy sources? 

b) What is their chronology? 

oUowing prerequisite investigations, whose results would provide 
a basis for answering the major questions, were suggested: 

(1) The distribution of surface chemical and isotopic compositions, 
including trace elements. 

(2) The internal structure and petrology and the physical state of 
the interior. 

(3) The present thermal regime including internal temperature dis- 
tribution, surface heat flow, and abundances and distribution of 
heat sources. 

(4) The correlation among morphology, composition, and chronology 
of surface material. 



At post-ApoZZo time, it is unlikely that satisfactory answers to these 
questions will have been obtained. Automated rovers will not provide 
direct answers to the major questions and prerequisite investigations, 
but they can provide a unique means for step-by-step accumulation of 
essential data. 



129 



Essential Rover Measurements 

The optimum geological measurements for rovers are those that 
characterize surface geological units in terms of morphology and com- 
position and those of a geophysical nature that permit determination of 
deeper subsurface structure. Desirable parameters for measurement are 
those that are likely to vary over a long traverse in a way that can be 
correlated with lithology or morphology as deduced from Apollo and 
Lunar Orbiter photographs. Undesirable parameters are those that are 
likely to vary randomly over the whole surface or with time. 

Based on the above criteria, a few relatively simple, fundamental 
surface measurements are essential for a traverse over previously unex- 
plored lunar regions. These measurements are practical and likely to be 
most feasible within the expected constraints of a rover program. 

(1) Imaging. There should be: 

(a) Continuous high-resolution imaging in the visible spectrum, 
ideally in color and with spatial resolution of at least 0.1 mm 
in close-up mode. 

(b) Monoscopic and stereoscopic panoramic views, and magni- 
fied views of selected outcrops as well as of individual rock 

fragments. 

(c) Search for bedrock, and delineation of field relations of rock 
units; e.g., distinction of intrusive and depositional contacts. 
It is important that the undisturbed regolith surface be 
viewed in situ and close up, since return of undisturbed 
surface material to Earth is difficult. 

(2) Characterization of surface material. The bulk elemental composi- 
tion of surface materials must be found using some easily meas- 
ured parameters. Gamma-ray spectrometry and spectral reflec- 
tance are possible techniques. 

(3) Elemental and mineralogical characterizations. Detailed elemental 
and mineralogical characterization via neutron activation and 
X-ray diffraction methods can be made on selected specimens at 
sites of special interest (Reference 18). 

(4) Geophysical measurements should be made as follows: 

(a) Gravity profiles (discrete measurements with spacing de- 
pending on observed variations). 



130 



(b) Heat flow measurements with sensitivity sufficient for 
detecting fluxes of 4.184 X 10-« J-s-^-cm-^ (10-^ cal-s-^-cm-^).^ 
This is a difficult measurement and may not be feasible for 
an automated rover. 

(c) Seismic measurements using deployed surface charges as 
well as natural events. 

Instrumentation Techniques 

Imaging 

The essential instrument for guiding and navigating a rover and for 
observing and sampling the lunar surface to achieve the above objectives 
is an imaging system. The technical requirements on image quality and 
telecommunications bandwidth are such that two types of cameras are 
needed; the total number of cameras may be more than two, for redun- 
dancy or for convenience in achieving desired fields of view. The two 
types of cameras and their functions are listed in Table 1. 

Table 1. Rover imaging systems 



JPL imaging sensor 
requirement 



Fimction 



Lunokhod design 



Television 

Near field ahead and 
to sides 

Close-Tip with 
magnification 

Far field 

Photofacsimile 
Horizon panorama 



Near field 



Guidance (driving) 
and sampling 

Sample investigation 

Magnified views of 
distant features 



Landmark navigation 
and geologic 
reconnaissance 

Geologic observation 
and redundancy with 
TV 



Two forward-looldng TV 
cameras, one wide-angle, 
one narrow-angle 



Four telephotometers, 
two scanning horizon, 
two scanning fore and 
aft through vertical 



On the basis of Surveyor and Apollo observations, a survey of opinions 
among scientists, and laboratory tests, some conclusions of the JPL 
imaging studies were: 

(1) Stereo is desirable but not essential in the near field for driving. 



iWhere applicable, the International System of Units is stated first, followed by the 
customary units in parentheses. In each case, the value in parentheses represents 
the measured or calculated unit. 



131 



(2) Magnification and manipulation, i.e., changing illumination and 
viewing angles, are essential for the close-up petrologic analysis 
of samples, and a large depth-of-field is highly desirable. 

(3) Color is not needed for the panoramic or near-field lunar views, 
but is highly desirable in the magnified close-ups. 

The Lunokhod system apparently does not include color and is not 
optimized for stereo, and sample collection and manipulation are not 
provided. However, the system does have the main characteristic recom- 
mended; namely, it uses television for the near-field and driving functions 
(where speed of display is more important than picture quality) and 
photofacsimile for panoramic reconnaissance (where high resolution 
and high photometric, dimensional, and spectral fidelity are desired), 
with some overlap for redundancy. 

Orientation and Navigation 

On the basis of studies, laboratory experiments, and field tests (Refer- 
ence 7) in the California desert (Figures 4 and 5), the JPL teams devised 
a practical scheme for landmark navigation and evaluated the require- 
ments for rover imaging and other sensors as well as ground displays and 
command functions. Table 2 summarizes these results. 

Table 2. Rover navigation 



JPL requirement 



Function 



Lunokhod design 



Horizon landmark identifi- 
cation and bearings 

Sun, Earth azimuth and 
elevation 

Vehicle pitch, roll and 
heading relative to local 

vertical 

Distance travelled 



Direction travelled 



Position fix 

Orientation, rough 
position 

Orientation and 
hazard limit 
sensing 

Dead reckoning 



Dead reckoning 



Telephotometers, i.e., 
photofacsimile cameras 

Telephotometers and 
antenna servo positions 

Tilt sensors in 

telephotometer field of 
view, and sun or shadow 
azimuth 

Odometer on extra towed 
wheel, sensors on 
driving wheels 

Unknown 



It is not obvious from announcements made to date that the Lunokhod 
uses or needs a landmark navigation system, since it moved only a few 
kilometers and then returned to its landing point. It does have all the 
other functions listed in Table 2. The JPL studies ( Reference 19 ) showed 
that landmark navigation is the only practical way to attain the accuracy 
needed on a traverse of hundreds of kilometers. Competing techniques 
such as inertial or celestial navigation require more instrumentation and 



132 






11 



c 

1 .5 

"3 5 

2 §• 
OJ c 

a ® 
E .£ 

Si 

I! 

M 5 
■s > 

C -D 
g I 

> "i 



£ 

3 
M 



133 



I1T1 



=ic 



Figure 5. Interior of van (simulating Earth-based control center) showing pictorial 
displays: (top) panorama, (center) magnified yiew of part of horizon, (bottom) 
close-up of samples 

do not offer comparable performance for the particular missions con- 
sidered feasible early in a surface exploration program. Of course, the 
use of landmarks is limited to areas previously mapped, for example, by 
lunar orbiters; this is not a severe constraint for the missions studied. 

Other Scientific Instruments 

In addition to the television and facsimile instruments and sample 
manipulation device, it was concluded (as mentioned above and in 
References 5, 7, and 8) that early lunar rovers should carry limited in- 
strumentation for measuring surface chemical composition, e.g., an X-ray 
diffractometer/spectrometer, and also, if possible, geophysical instru- 
ments such as a gravimeter and precision ranging transponder. 

The Lunokhod payload includes an X-ray spectrometer that can be 
deployed to the lunar surface to measure soil composition, a pene- 



134 



trometer-and-vane device for measuring soil bearing and shear strength, 
and radiation detectors for determining the lunar radiation background 
environment. In addition, the rover carries an X-ray telescope aimed near 
the zenith with sensitivity in the 2 X 10-^» to 10 X 10-"-m (2 to 10-1) 
region and about a 52-mrad (3-deg) field of view, and a French-built 
laser retroreflector. 

The Soviet spacecraft therefore is attempting experiments closely 
similar to those recommended for U.S. automated rovers for initial 
reconnaissance, but with relatively less emphasis on lunar mineral 
sampling and internal properties, and relatively more emphasis on radia- 
tion and astronomical measurements. Though the precision ranging 
experiment was recognized in the JPL studies as very important in the 
study of Earth-Moon motions, it was not recommended that the rover 
carry a laser reflector, since this appeared more suitable as a fixed-site 
experiment. The Lunokhod retroreflector, used intermittently now while 
the rover is stopped at night, can presumably continue in use after the 
machine finally stops moving. 

The Lunokhod design appears adequate for every critical function, 
with the exception that the long traverse mission requires an order of 
magnitude higher average speed than Lunokhod 1 has demonstrated. 
The interaction among rover power supply and demand, lunar lighting, 
time needed for experiments, safe driving speeds, and ground-system 
duty cycle was worked out in the JPL studies. The resulting conclusion 
was that night survival, as now achieved by Lunokhod 1, would be 
essential because at best only a few tens of kilometers could be covered 
during each lunar day. The slow progress of Lunokhod 1 may be in 
part due to power-system limitations, but also probably reflects a proper 
degree of caution at the start of this new class of missions on the Moon. 



References 

1. Exploration of the Moon, the Planets, and Interplanetary Space, Re- 
port 30-1. Edited by A. R. Hibbs. Jet Propulsion Laboratory, Pasadena, 
Calif., Apr. 30, 1959. 

2. Lunar Exploration-Strategy for Research 1969-1975, National Acad- 
emy of Sciences, Space Science Board, Washington, D. C, Sept. 1969. 

3. 1967 Summer Study of Lunar Science and Exploration, Santa Cruz, 
Calif., NASA SP-157. Edited by W. N. Hess. National Aeronautics 
and Space Administration, Washington, 1967. 

4. Adams, J. B., et al., "Strategy for Scientific Exploration of the Terres- 
trial Planets," Reviews of Geophysics, Vol. I, pp. 623-661, Aug. 1969. 



135 



References (contd) 



5. Brereton, R. G., "The Objectives for Roving Vehicles in a Lunar 
Exploration Program," in Supporting Research and Advanced Devel- 
opment, Space Programs Summary 37-52, Vol. Ill, pp. 253-255. Jet 
Propulsion Laboratory, Pasadena, Calif., Aug. 31, 1968. 

6. Brereton, R. G., "Lunar Mission Planning," in Supporting Research 
and Advanced Development, Space Programs Summary 37-54, 
Vol. Ill, pp. 230-238. Jet Propulsion Laboratory, Pasadena, Calif., 
Dec. 31, 1968. 

7. Brereton, R. G., and Howard, E. A., "Comments on Geological Ob- 
servations From an Automated Vehicle (Field Test)," in Supporting 
Research and Advanced Development, Space Programs Summary 
37-55, Vol. Ill, pp. 258-263. Jet Propulsion Laboratory, Pasadena, 

Calif., Feb. 28, 1969. 

8. Brereton, R. G., "An Active Seismic Experiment for an Automated 
Roving Vehicle," in Supporting Research and Advanced Develop- 
ment, Space Programs Summary 37-56, Vol. Ill, pp. 213-216. Jet 
Propulsion Laboratory, Pasadena, Calif., Apr. 30, 1969. 

9. Brereton, R. G., "Lunar Surface Gravity Investigations," in Supporting 
Research and Advanced Development, Space Programs Summary 37- 
57, Vol. Ill, pp. 1-6. Jet Propulsion Laboratory, Pasadena, Calif., June 

30, 1969. 

10. Brereton, R. G., Ulrich, G. E., and Dahlem, D. H., "Imaging and 
Sampling Requirements for an Automated Lunar Roving Vehicle," 
in Supporting Research and Advanced Development, Space Programs 
Summary 37-60, Vol. Ill, pp. 1-3. Jet Propulsion Laboratory, Pasa- 
dena, Calif., Dec. 31, 1969. 

11. Brereton, R. G., "Geophysical Experiments for the Manned Portion 
of a Lunar Roving Vehicle Mission," in Supporting Research and 
Advanced Development, Space Programs Summary 37-61, Vol. Ill, 
pp. 1-4. Jet Propulsion Laboratory, Pasadena, Calif., Feb. 28, 1970. 

12. Brereton, R. G., et al., "A Miniaturized Absolute Gravimeter for 
Terrestrial, Lunar, and Planetary Research," in Supporting Research 
and Advanced Development, Space Programs Summary 37-62, Vol. 
Ill, pp. 1-5. Jet Propulsion Laboratory, Pasadena, Calif., Apr. 30, 

1970. 

13. Brereton, R. G., "Automated Post-Missions for the Lunar Roving 
Vehicle," in Supporting Research and Advanced Development, Space 
Programs Summary 37-62, Vol. Ill, pp. 5-8. Jet Propulsion Labora- 
tory, Pasadena, Calif., Apr. 30, 1970. 



136 



References (contd) 

14. Strand, J. N., "Tests of Instruments Proposed for the Scientific Pay- 
load of a Lunar Rover," in Supporting Research and Advanced 
Development, Space Programs Summary 37-62, Vol. Ill, pp. 15-18. 
Jet Propulsion Laboratory, Pasadena, Calif., Apr. 30, 1970. 

15. Brereton, R. G., "Mission Objectives for a Lunar Roving Vehicle," 
in Supporting Research and Advanced Development, Space Programs 
Summary 37-64, Vol. Ill, pp. 1-3. Jet Propulsion Laboratory, Pasa- 
dena, Calif., Aug. 31, 1970. 

16. Soviet-Bloc Research in Geophysics, Astronomy, and Space, JPRS 
51991, No. 242. Joint Publications Research Service, Dec. 15, 1970. 

17. Soviet-Bloc Research in Geophysics, Astronomy, and Space, JPRS 
52087, No. 243. Joint Publications Research Service, Dec. 30, 1970. 

18. Nash, D. B., Sampling of Planetary Surface Solids for Unmanned 
In Situ Geological and Biological Analysis: Strategy, Principles, and 
Instrument Requirements, Technical Report 32-1225. Jet Propulsion 
Laboratory, Pasadena, Calif., Nov. 15, 1967. 

19. Lewis, R. A., "A Computerized Landmark Navigator: Development 
and Test Plan," in Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 1-2. Jet Propulsion 
Laboratory, Pasadena, Calif., Oct. 31, 1970. 



137 



Author Index With Abstracts 



ADAMS, J. B. 

AOl Surveyor Final Report— Lunar Theory and Processes: 
Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gault (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 
H. iViasursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 

A02 Surveyor Final Report— Lunar Theory and Processes: 
Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 

of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 

R. A. Phinney (Princeton University), and E. M. Shoemaker (U.S. 

Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

For abstract, see Gault, D. E. 



AKLONIS, J. J. 

A03 Viscoelastic Behavior of Elastomers Undergoing 
Crosslinking Reactions 

J. Moacanin and J. J. Akionis (University of 
Southern California) 



139 



Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-66, Vol. Ill, pp. 187-189, 

December 31, 1970 

For abstract, see Moacanin, J. 



AKYUZ, F. A. 

A04 VISCEL— A General-Purpose Computer Program for Analysis 
of Linear Viscoelastic Structures: User's Manual 

F. A. Akyuz and E. Heer 

Technical Memorandum 33-466, Vol. I, February 15, 1971 

A general-purpose computer program (VISCEL) for the solution 
of linear viscoelastic structures is described. VISCEL is an exten- 
sion of the program ELAS, which has been developed for the 
in-core solution of linear equilibrium problems of structural 
mechanics of limited size (approximately 500-600 unknovi'ns) and 
with a minimum of computer time (3-4 min in the IBM 7094, 
Model I). The standard features and capabilities of ELAS have 
been preserved. The solution is obtained by means of the dis- 
placement method and the finite element technique, together 
with the use of incremental time steps and a synchronized mate- 
rial property concept. The solution is obtained at the end of 
each time step as incremental and accumulative displacements and 
stresses. The recursive equations expressing the property of the ma- 
terial with memory have been incorporated in the computations. 
Also, a scheme which employs constant time steps in the logarith- 
mic scale can be used to minimize the number of computations 
resulting from the accumulative effects of the material memory. 

Almost any structure with linear elastic material properties and 
continuous structures with linear viscoelastic material prop- 
erties can be handled by VISCEL. The program is written in 
FORTRAN IV language for use in 32K IBM 7094 machines with 
a standard hardware configuration having a minimum of 15 
system units. The source deck consists of about 8600 cards; the 
object deck contains about 1500 cards. The physical program 
VISCEL is available from the Computer Software Management 
and Information Center (COSMIC), the NASA agency for the 
distribution of computer programs. 

ALLEY, C. 0. 

A05 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 



140 



S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of 
Hawaii), and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-150, 
March 1970 

For abstract, see JaflFe, L. D. 

ANDERSON, T. 0. 

A06 Integrated-Circuit Packaging System 

T. 0. Anderson and D. Bodkin 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 29-31, November 30, 1970 

This article describes a model of an integrated-circuit packag- 
ing system for use as the Deep Space Network standard. The 
basic technique used was first developed in the construction of 
a video data compressor reported earlier. The advanced model 
of this packaging scheme has been adopted, with minor modifi- 
cations, for the prototype of the telemetry data decoder assembly 
for Pioneer F to be used throughout the Deep Space Instrumen- 
tation Facility. 

ARNETT, J. C. 

A07 Evaluation of 26- to 32-AWG Wire for Outer Planet 
Mission Applications 

J. C. Arnett 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 142-147, 
Octobers!, 1970 

Tests were performed establishing dimensional, physical, elec- 
trical, and handling characteristics of small-gage wire for outer 
planet mission applications. Environmental tests in vacuum and 
low temperature were made to evaluate exposure-related degra- 
dation effects. The most promising candidates for volume- and 
weight-limited electronic packaging applications on future space- 
craft were selected. 



141 



ASHLOCK, J. C. 

A08 Applying Nonadaptive Transversal Filters to Playback of 
Digital Tape Recorder Signals 

J.C.Ashlock 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ml, pp. 148-152, 
October 31, 1970 

Previous work leading to an attractive detector for use in bit 
detection of digital tape recorder signals is reviewed. It is shovsoi 
that the design of the matched and transversal filters in this 
detection scheme can be approached from more than one point 
of view; two of these approaches are examined in detail and 
experimentally compared for the case of 10,000 bits/in./track. 
Detector waveforms and bit error rate data are given. 



BACK, L. H. 

BOl Changes in Heat Transfer From Turbulent Boundary Layers 
Interacting With Shock Waves and Expansion Waves 

L. H. Back and R. F. Cuffel 

AlAA J., Vol. 8, No. 10, pp. 1871-1873, October 1970 

This article discusses heat transfer from turbulent boundary layers 
in supersonic flows where changes in surface curvature can pro- 
duce shock waves and expansion waves (e.g., corner flows) or 
where shock waves generated elsewhere in the flow impinge on 
the boundary layer. Heat-transfer measurements are presented in 
these interaction regions, and a rather simple method involving 
the integral form of the energy equation is used to estimate the 
change in heat transfer that is observed. The prediction is then 
compared to other experimental data obtained at shock impinge- 
ment locations. 

B02 Relationship Between Temperature and Velocity Profiles in a 
Turbulent Boundary Layer Along a Supersonic Nozzle 
With Heat Transfer 

L. H. Back and R. F. Cuffel 

AlAA J., Vol. 8, No. 11, pp. 2066-2069, November 1970 

The relationship between measured temperature and velocity 
profiles is presented for an accelerating, turbulent boundary- 
layer flow of air through a cooled, convergent divergent nozzle. 
Boundary-layer measurements were made upstream, along the 



142 



convergent section, and near the end of the divergent section 
where the flow is supersonic. These measurements span a rela- 
tively large flow speed range, the inlet and exit Mach numbers 
being 0.06 and 3.7, respectively. The operating conditions were 
such that the boundary layer remained essentially turbulent; i.e., 
laminarization did not occur in the accelerating flow. The wall 
was cooled externally, the ratio of wall-to-stagnation temperature 
being 0.43-0.56. 

The measurements are also related to current interest in the struc- 
ture of very-high-speed turbulent boundary layers. For example, 
measurements are often made near the exit of supersonic nozzles 
with wall cooling. The present measurements provide information 
on the upstream history of the accelerating flow and on the 
relationship of upstream profiles to the profile near the nozzle exit. 



BALL, J. E. 

BOS The Mariner VI and VII Flight Paths and Their Determination 
From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 



BAWIFORD, R. M. 

B04 Equivalent Spring-Wfass System for Normal Modes 

R. M. Bamford, B. K. Wada, and W. H. Gayman 

Technical Memorandum 33-380, February 15, 1971 

Since the lower resonant frequencies are of interest in most 
structural problems, a significant reduction of independent 
variables is possible by the use of the normal modes of struc- 
tural subsystems as independent variables. This memorandum 
describes a technique that can be used to generate equivalent 
spring-mass models for the normal modes of a structural sub- 
system when the generalized mass matrix and resonant frequen- 
cies are available. Where modal truncation is employed, the 
residual mass matrix is used to preserve the correctness of 
the rigid-body mass properties. Applications of the modeling 
technique and the residual mass matrix are discussed. 



143 



BANES, i. 

B05 Heat-Sterilizable Battery Development 

[August-September 1970] 

R. Banes 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 80-81, 
October 31, 1970 

In the program to develop heat-sterilizable silver-zinc cells, pro- 
duction model cells of the 70-A-h primary design have been 
characterization-tested and are being evaluated under space flight 
conditions. The goals for the 25-A-h cells capable of ninety 60% 
cycles have been attained and this development has been discon- 
tinued. The development of the foiir hundred 60% cycle cell 
has been modified to provide for more experimental work before 
testing to simulate flight profiles. 

BARENGOLTZ, J. B. 

B06 Jupiter's Electron Dose Calculations on Metal Oxide 

Semiconductor Structures 

S. P. Li and J. B. Barengoltz 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 166-170, 
December 31, 1970 

For abstract, see Li, S. P. 



BATELAAN, P. D. 

B07 Improved RF Calibration Techniques: PDS Cone Waveguide/ 

Pofarimeter Calibrations 

P. D. Batelaan, B. Seidel, and R. B. Lyon 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 61-63, November 30, 1970 

The waveguide losses and reflection coefficient measurements 
are presented for the polarization diversity S-band (PDS) cone. 
Tests were also conducted to verify the polarimeter capabilities of 
the PDS cone. Results indicated excellent agreement with theory. 

BATTERSON, S. A. 

BOS Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 



144 



S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of 
Hawaii), and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffe, L. D. 

BAUMAN, A. J. 

B09 Isolation and Characterization of Coal in Antarctic 
Dry-Valley Soils 

A. J. Bauman, E. M. Bollin, G. P. Shulman, and R. E. Cameron 

Antarc. J. U.S., Vol. V, No. 5, pp. 161-162, 
September-October 1970 

The Allison wet combustion method appHed to soils from two 
Antarctic dry -valley sites showed that they contained 0.1-0.7% 
"organic carbon." However, solvent extraction and combined 
pyrolysis/gas chromatography /mass spectrometry unexpectedly 
showed no indication of the free or kerogen-bound carbon com- 
pounds usually present in these soils. Heavy-liquid density flota- 
tion and oxidative differential thermal analysis were then applied 
to the samples, both before and after digestion with HF, in an 
effort to elucidate the nature of the anomalous "Allison carbon." 
Sub-surface samples were collected at the junction of McKelvey 
and Victoria Valleys, 1.5 km west of Lake Vida, and in Wheeler 
Valley above Miller Glacier, opposite Killer Ridge. The results 
of the investigation are presented. 

BAUIVIERT, L D. 

BIO Evolution and Coding: Inverting the Genetic Code 

L. D. Baumert and D. Cantor (University of California, 
Los Angeles) 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 41-44, 
October 31, 1970 

The amino acid sequences of proteins together with a presumed 
evolutionary model have been used to specify the genetic nucleo- 



145 



tide sequences of these proteins. Sample results are presented. The 
number of possible nucleotide sequences for human cytochrome c 
has now been reduced by a factor of 1.4 X 10^. 



BERMAN, P. A. 

B 1 1 Effects of Lithium Doping on the Behavior of Silicon 

and Silicon Solar Cells 

P. A. Berman 

Technical Report 32-1514, February 1, 1971 

The Jet Propulsion Laboratory is sponsoring investigations into 
the applicability of lithium doping for improvement of silicon 
solar cell radiation resistance. This report discusses the author's 
interpretation of the results of the industry programs, in par- 
ticular the efforts to improve cell processing techniques and the 
experiments conducted to improve the theoretical understanding 
of the action of lithium in irradiated silicon and silicon solar cells. 
The major conclusions reached as a result of the investigations are 
presented, and suggestions for future work are made. It appears 
that lithium-doped solar cells can be fabricated which exhibit 
(recovered) efficiencies significantly in excess of efficiencies 
associated with state-of-the-art N/P solar cells after exposure 
to high fluences of 1-MeV electrons and neutrons. 

B12 Effects of High-Temperature, High-Humidity Environment 
on Silicon Solar Cell Contacts 

R. K. Yasui and P. A. Berman 

Technical Report 32-1520, February 15, 1971 

For abstract, see Yasui, R. K. 

B13 Activation Energy of Annealing in Lithium-Doped Silicon 

P. A. Berman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 68-69, 
October 31, 1970 

A very strong point of agreement among investigators is that the 
activation energy associated with neutralization of radiation- 
induced defects in hthium-doped silicon (whether the defects 
be caused by 1-MeV electrons, 30-MeV electrons, or neutrons) is 
very close to the activation energy associated with diffusion of 
lithium in silicon and gives strong support to the theory that 
neutralization of radiation-induced defects is a result of lithium 



146 



diffusion to the defect sites. The experimental results and analysis 
performed by the various investigators leading to this conclusion 
are summarized. 



BERWIN, R. 

B14 RF Techniques: Superconducting Magnet for X-Band Maser 

R. Berwin and P. Dachel 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 45-47, 
October 31, 1970 

The current experimental development of an X-band supercon- 
ducting magnet is reported. The advantages of using the super- 
conducting magnet as an integral part of the traveling wave 
maser in the cloud-cycle refrigerator are examined in relation to 
the presently used external permanent magnets. 

BODKIN, D. 

B15 Integrated-Circuit Packaging System 

T. 0. Anderson and D. Bodkin 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 29-31, November 30, 1970 

For abstract, see Anderson, T. O. 

BOLLIN, E. M. 

B16 Isolation and Characterization of Coal in Antarctic 
Dry-Valley Soils 

A. J. Bauman, E. M. Bollin, G. P. Shulman, and R. E. Cameron 

Antarc. J. U.S., Vol. V, No. 5, pp. 161-162, 
September-October 1970 

For abstract, see Bauman, A. J. 

BOUNDY, R. A. 

B17 Fabrication Development of Lightweight Honeycomb-Sandwich 
Structures for Extraterrestrial Planetary Probe Missions 

R. G. Naglerand R. A. Boundy 

Technical Report 32-1473, January 15, 1971 

For abstract, see Nagler, R. G. 



147 



BOWERS, M. T. 

B18 On the Relative Proton Affinity of Argon and Deuterium 

M. T. Bowers (University of California, Santa Barbara) and 
D. D. Elleman 

J. Am. Chem. Soc, Vol. 92, No. 25, pp. 7258-7262, 

December 16, 1970 

In mixtures of Ar and Da at high pressures, the following ion- 
molecule reaction scheme is observed: 

D2++ D,-^(D3i* + D (1) 

(D3i* + (D,)^^(D3-)t + D, (2) 

(D3+)* + Ar -^ ArD+ + D, (3) 

(D3+)t + Ar-T^ ArD+ + D, (4) 

ArD+ + D,-^D3-^ + Ar (5) 

(D3*)* has of the order of 2 eV of energy according to the experi- 
ments of Leventhal and Friedman. (D3+)t is the lowest vibra- 
tional state obtainable by collision of (D3+)* with D2. The results 
given here suggest that (D3+)f is not the ground state but has at 
least 1 and possibly 2 quanta of vibrational energy (i.e., 10-20 
kcal/mol). From pressure dependence studies, it is shown that a 
maximum of three collisions is needed to moderate all (D3+)* to 
(D3+)t. From reaction 5, PA(D2) > PA(Ar). From threshold- 
double-resonance experiments on reaction 4, PA(D2)^ ^ PA(Ar) 
+ 7 kcal/mol, with an uncertainty of ±5 kcal/mol. PA(D2)t is 
the energy required to remove D+ from (Ds*)!. The intrinsic pro- 
ton (or deuteron) affinity of D2, PA(D2), is felt to be 10-20 
kcal/mol larger than that of PA(Do)t. 

BRANDT, R. D. 

B19 Computer Refreshed Display 

R. D. Brandt 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. ill, pp. 16-18, 
October 31, 1970 

This article describes the design philosophy and hardware im- 
plementation of a computer refreshed display which has a repe- 
tition rate of approximately 28 fields per second. The display is 
used to view video information that has been processed by a 
digital computer. The display greatly reduces the time necessary 
to yield the end process because it allows the operator to view 
the intermediate processes while the "job" is being run on the 
computer. 



148 



BRATENAHL, A. 

B20 Experimental Study of Magnetic Flux Transfer at the 
Hyperbolic Neutral Point 

A. Bratenahl and C. M. Yeates 

Phys. Fluids, Vol. 13, No. 11, pp. 2696-2709, November 1970 

Reported here is a laboratory study of a plasma flow process 
sometimes referred to as the severing and reconnecting of mag- 
netic field lines at a hyperboHc or X-type neutral point. It is 
found that a hyperbolic pinch develops at the neutral point, 
resulting in plasma compression. The ohmic electric field of the 
pinch current enables field line reconnection to take place through 
resistive diffusion. The reconnection rate is substantially increased 
by a reduction in the size of the pinch region effected by flow 
adjustment through pairs of stationary slow-mode shocks in a 
manner similar to that deduced and described by Petschek. 
Strong evidence is presented for this wave-dominated configura- 
tion. However, it is found that the pinch current becomes pro- 
gressively concentrated at the neutral point and along the shock 
loci until eventually a critical current density is reached, marked 
by a sudden and large anomalous increase in resistivity as pre- 
dicted by Friedman and Hamberger. At this point the wave- 
assisted diffusion mode is terminated and there is observed: (1) a 
cutoff in pinch current, (2) a large increase in the electric field, 
(3) a corresponding increase in reconnection rate, and (4) the 
generation of a system of large-amplitude fast-mode waves. The 
waves, bearing evidence of the onset of plasma turbulence, effect 
a rapid and gross redistribution of flux among the cells defined 
by the separatrix and blow the slow-mode shocks off down- 
stream. The increased electric field raises the possibility of rapid 
magnetic energy dissipation through acceleration of particles to 
high energy. 



BRECKENRIDGE, W. G. 

B21 The Mariner VI and VII Flight Paths and Their Determination 
From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 
For abstract, see Gordon, H. J. 



149 



BRERETON, R. G. 

B22 Lunar Elevation Correction for Gravity iVleasurements 

R. G. Brereton 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 1-3, 

December 31, 1970 

This article reviews some of the corrections that will be required 
for lunar surface gravity observations. Because the lunar Bouguer 
correction is smaller than its terrestrial counterpart, elevation 
control for lunar gravity surveys can be reduced by a factor of 
2 for most field operations. 

BUFFINGTON, J. P. 

B23 Post- Detection Recorder Evaluation 

J. P. Buffi ngton 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 136-137, November 30, 1970 

The difficulties in reproducing baseband telemetry recordings 
have been attributed to time displacement error. This article 
discusses a method of comparing tape transports with good accu- 
racy. The results of pragmatic tests are presented on a particular 
tape transport having very low time displacement error on which 
phase-modulated telemetry data are recorded and subsequently 
demodulated, using a phase-locked loop subcarrier demodulator 
assembly. 



BURNS, T. L 

B24 DSS Upgrades for Mariner Mars 1971 

T. L. Burns 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 114-115, November 30, 1970 

During the period July through December 1970, the deep space 
stations (DSSs) committed to the Mariner Mars 1971 Project 
have undergone or are scheduled to undergo reconfiguration in 
preparation for the mission. The reconfiguration consists of block 
upgrades of subsystems, rearrangement of the control and com- 
munications rooms to provide space for new equipment, and 
major maintenance on older equipment. The work performed on 
each subsystem is described in this article. 



150 



CALLAHAN, P. S. 

COl DSN Progress Report for November-December 1970: Probing 
the Solar Plasma With Mariner Radio Metric Data, 
Preliminary Results 

P. F. MacDoran, P. S. Callahan, and A. I. Zygielbaum 

Technical Report 32-1526, Vol. I, pp. 14-21, February 15, 1971 

For abstract, see MacDoran, P. F. 

CAMERON, R. E. 

C02 Soil Microbial and Ecological Investigations in the 
Antarctic Interior 

R. E. Cameron, R. B. Hanson, G. H. Lacy, and F. A. Morelli 

Antarc. J. U.S., Vol. V, No. 4, pp. 87-88, July-August 1970 

In November-December 1969, 10 soil samples were collected 
aseptically from the surface to the depth of permafrost at five 
sites on a traverse west of Coalsack Bluff (approximately 84° 15'S, 
162°E). Another 14 samples were collected from five sites on a 
traverse north of the Bluff. During the latter traverse, a camp 
site was established for 1 wk just below the west end of "Coal- 
sack Bluff West," and environmental measurements were made 
continually or every 3 h for soil and/or microclimatic character- 
istics. Air sampling for microflora was also undertaken on four 
sides of the camp site. The results of the investigations are briefly 
discussed. 

COS Microbiological Analyses of Snow and Air From the 
Antarctic Interior 

G. H. Lacy, R. E. Cameron, R. B. Hanson, and F. A. Morelli 

Antarc. J. U.S., Vol. V, No. 4, pp. 88-89, July-August 1970 

For abstract, see Lacy, G. H. 

C04 Isolation and Characterization of Coal in Antarctic 
Dry-Valley Soils 

A. J. Bauman, E. M. Bollin, G. P. Shulman, and R. E. Cameron 

Ar)tarc. J. U.S., Vol. V, No. 5, pp. 161-162, 
September-October 1970 

For abstract, see Bauman, A. J. 



151 



CAMPBELL, J. K. 

COS The Mariner VI and VII Flight Paths and Their Determination 

From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 

T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 
For abstract, see Gordon, H. J. 

CANTOR, D. 

C06 Evolution and Coding: Inverting the Genetic Code 

L. D. Baumert and D. Cantor (University of California, 
Los Angeles) 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 41-44, 
October 31, 1970 

For abstract, see Baumert, L. D. 

CAPEN, C. F. 

C07 Observational Patrol of Mars in Support of Mariners V} and VII 

C. F. Capen 

Technical Report 32-1492, June 15, 1970 

A summary of the physical appearance of Mars during the 1969 
apparition is presented for use in planetary research and in sup- 
port of the Mariner VI and VII missions. An account is given of 
the seasonal meteorological activity and surface conditions before 
and during the Mariner encounters. Diameter measurements of 
the regressing south polar cap are tabulated. For comparison 
with Mariner pictures, a current Regional Mars Map 1969 of 
longitudes 240 to 100 deg (inclusive) was prepared from high- 
resolution observations (0.1 to 0.2 arc sec) acquired during late 
Martian summer. Selected photographs and drawings are repro- 
duced for reference with the text. 

CAPUTO, R. S. 

COS Review of Radioisotope Thermoelectric Generators for 

Outer Planet Missions 

R. S. Caputo 



152 



Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. I!l, pp. 70-75, 
December 31, 1970 

The nominal performance of current radioisotope thermoelectric 
generator (RTG) programs is reviewed and performance predic- 
tions are made for long-term operations based on the most recent 
module data. The RTG programs that are considered for service 
of up to 5 or 7 yr are Transit (Isotec), Pioneer (SNAP 19-TAGS), 
and SNAP 27 Integral, which all use a lead telluride thermoelec- 
tric material; the multi-hundred watt (MHW) silicon germanium 
generator is considered for missions as long as 12 yr. The MHW 
system, using the advanced technology fuel capsule for near-term 
missions or the less-developed HeHpak heat source for later mis- 
sions, holds the greatest potential for future RTG applications. 

CARTER, K. R. 

C09 DSN Progress Report for November-December 1970: SFOF 
Configuration Control 

K. R. Carter 

Technicai Report 32-1526, Vol. I, pp. 122-123, 
February 15, 1971 

This article describes the need for and design of a Space Flight 
Operations FaciHty (SFOF) configuration control system based 
on the highly dynamic nature of the facility and the unique, 
critical requirements levied upon it by multiple and simultaneous 
flight projects supported by various JPL functional organizations. 
Only hardware changes are discussed. 

CASPERSON, R. 

CIO DBS 61/63 Facility Modifications and Construction 

R. Casperson, G. Kroll, and L. Kushner 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 154-158, November 30, 1970 

DSS 61/63 (Robledo Deep Space Station) is being reconfigured 
to an 85-ft-diam/210-ft-diam antenna complex. This article 
describes the facility modifications and construction necessary 
to accomplish this reconfiguration. 

CHADWICK, H. D. 

Cll Signal Design for Single-Sideband Phase Modulation 
H. D. Chadwick 



153 



Supporting Research and Advanced Devetopment, 
Space Programs Summary 37-66, Vol. Ill, pp. 54-58, 

December 31, 1970 

A single-sideband phase-modulated (SSB-PM) signal is a func- 
tion of both a time function and its Hilbert transform. In this 
article a set of time functions is derived whose Hilbert transform 
contains minimum energy outside of a specified time interval. 
These functions are useful for reducing the intersymbol inter- 
ference problem that arises when SSB-PM signals are detected 
with a correlation detector. 



CHAHINE, M. T. 

C12 Inverse Problems in Radiative Transfer. Determination of 

Atmospheric Parameters 

M. T. Chahine 

Technical Report 32-1351, R. II (Reprinted from J. Atmos. ScL, 
Vol. 27, No. 6, pp. 960-967, September 1970) 

It is shown that the relaxation method for inverse solution of the 
full radiative transfer equation leads to unique temperature pro- 
files. Apart from its attractive simplicity, the algorithm is also 
capable of discriminating between noise and valid information 
without any need for data smoothing. A set of new inverse prob- 
lems is formulated for the determination of the concentration of 
absorbing gases in an atmosphere, the extent and height of 
clouds, and surface elevations. The proposed methods are illus- 
trated by examples in the earth's atmosphere for the region of 
the 4.3-fj. CO, band. 



CHAD, B. T. 

C13 Thermal Modeling of Spacecrafts With Imperfect Models 

B. T. Chao (University of Illinois) 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 136-137, 
October 31, 1970 

Theoretical requirements for thermal scale modeling of un- 
manned spacecrafts are well understood at the present time. Dif- 
ficulties arise in practice mainly because of their structural 
complexity. This study explored a concept of model testing, 
utilizing models that do not completely satisfy the similitude 
criteria. The concept is based upon representing the error states 
in a multi-dimensional euclidean space, separating the errors 



154 



into positive and negative groups, and extrapolating the error 
states to the zero error condition. 



CHAO, C. C. 

C14 Tracking System Analytic Calibration Activities for the 
Mariner Mars 1969 Mission 

B. D. Mulhall, C. C. Chao, N. A. Mottinger, P. M. Muller, 

V. J. Ondrasik, W. L. Sjogren, K. L. Thuleen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 

For abstract, see Mulhall, B. D. 

CI 5 DSN Progress Report for November-December 1970: A Cursory 
Examination of the Sensitivity of the Tropospheric Range 
and Doppler Effects to the Shape of the Refractivity Profile 

L F. Miller, V. J. Ondrasik, and C. C. Chao 

Technical Report 32-1526, Vol. 1, pp. 22-30, 
February 15, 1971 

For abstract, see Miller, L. F. 



CIS The Mariner VI and Vli Flight Paths and Their Determination 
From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinboid, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 

C17 Polar Motion: Doppler Determinations Using Satellites 
Compared to Optica! Results 

C. C. Chao and H. F. Fliegel 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 23-26, November 30, 1970 

Determinations of polar motion from doppler observation of 
navigation satellites made by the U.S. Naval Weapons Labora- 
tory over a 2-yr span (1968.0-1969.9) are compared to those of 
the three primary optical agencies for polar motion. Formulas 



155 



are given for estimating the true variance of each data source. 
The order of precision, measured by inverse standard deviation, 
of the various sources of polar motion is as follows : International 
Polar Motion Service, Bureau International de L'Heure, Inter- 
national Latitude Service, and U.S. Naval Weapons Laboratory. 
The doppler data are considered to be useful and important 
because they are presumably independent of the systematic 
errors affecting optical sources. 



CHEN, C.J. 

C18 Transition Probabilities for Xe I 

C. J. Chen and R. H. Garstang (University of Colorado) 

J. Quant. Spectrosc. Radiat. Transfer, Vol. 10, No. 12, 
pp. 1347-1348, December 1970 

Renewed interest in the spectra of the rare gases in connection 
with shock tubes, high temperature arcs, and lasers has led to 
fresh demands for transition-probability data. The rare gases 
show large departures from LS-coupling, and /7-coupling is also 
inadequate for many of the lower multiplets. Intermediate cou- 
pling calculations are therefore required. Calculations of this 
type have been performed for many transitions in Ne I, Ar I, and 
Kr I, but the authors were unable to find any studies of 
Xe I in the literature. Intermediate coupling line strengths for 
the 5p^6s-5p^6p and 5p'^6s-5p^7p transition arrays in Xe I 
have now been calculated. The final transition probabilities are 
tabulated in this article. 



CHEN, J. C. 

C19 Structural Analysis of a Solid Propellant Motor Under 
Axisymmetric Thermal and Pressure Loading 

J. C.Chen 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 176-178, 
October 31, 1970 

The stresses in a circular solid propellant grain section have been 
solved for axisymmetric transient thermal and pressure loading. 
The propellant is ass-umed to be linear, rheologically simple, 
viscoelastic material. The material property is represented by an 
exponential series in time which leads to a recurrence relation, 
eliminating the problem of recalculating the history of material 
response at each time step. 



156 



CHRISTENSEN, E. M. 

C20 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffa, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of 
Hawaii), and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffe, L. D. 



CLAUSS, R. C. 

C21 Low Noise Receivers: Microwave Maser Development 
[September-October 1970] 

R. C. Clauss 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 49-51, November 30, 1970 

Isolators used with comb-type traveling wave masers (TWMs) 
have been described previously in several Space Programs Sum- 
maries. Efforts to improve the isolator performance have been 
one of the objectives of maser development for several years. 
This work has improved TWM performance by reducing losses 
in the comb structure. A cryogenic switching circulator for use 
at X-band has been developed for JPL by E and M Laboratories. 
A versatile liquid nitrogen-cooled dewar system has been used 
for hard vacuum testing of the circulator. 



CLAYTON, R. M. 

C22 Experimental Observations Relating the Inception of Liquid 
Rocket Engine Popping and Resonant Combustion to the 
Stagnation Dynamics of Injection Impingement 

R. M. Clayton 

Technical Report 32-1479, December 15, 1970 

Ordinary liquid rocket combustion processes are never truly 
steady processes. They are usually observed as low-intensity. 



157 



random combustion-chamber pressure variations. However, a 
clearly distinguishable, aperiodic form of nonsteadiness is also 
frequently observed. This form of nonsteadiness is characterized 
by discrete, large-amplitude waves propagated throughout the 
combustion volume and is classified as popping. Popping and 
resonant combustion, as exhibited by annular and cylindrical 
versions of an 18-in.-diam engine, are found to occur for a par- 
ticular range of propellant temperature and mixture ratio con- 
ditions used in a boundary (near-wall) injection system. 

The correlation of these conditions of temperatxnre and mixture 
ratio is based on the argument that the impingement of two 
streams of equal dynamic pressure is inherently unsteady, and 
that small variations to either side of unity dynamic-pressure 
ratio can produce relatively large changes in the mixture and 
direction of the efflux from the impingement region. Pops are 
extremely effective in precipitating sustained combustion res- 
onance, unless the combustor is stabilized by control devices 
such as baffles. Reactive streams (hypergolic systems) and non- 
reactive streams (like-on-like systems) are discussed, as well as a 
proposed mechanism for producing initial combustion disturb- 
ances. 



C23 Injector Hydrodynamics Effects on Baffled-Engine Stability— A 
Correlation of Required Baffle Geometry With Injected 

Mass Flux 

R. M. Clayton 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 222-232, 

December 31, 1970 

Baffle stabilizing performance for the last of a series of three high- 
impedance research injectors is presented and the results for all 
three injectors are compared. It is shown that high dynamic- 
stability margins can be provided by baffles without extensive trial 
and error injector design changes when well-decoupled, reproduc- 
ible injection schemes are used iaitially. The stable configurations 
required (1) a large enough baffle length L to reduce the ratio 
of local mass flux (evaluated for individual injection elements 
at L) to the average mass flux over the chamber cross section, 
£^rei, to approximately 3 (out of a typical range for these experi- 
ments of 0.05 < Srei < 1000), and (2) simultaneously a sufficient 
number of baffle blades to reduce the ratio of average peripheral 
width of the baffle cavities to the first tangential wave length 
to <0.57. 



158 



COFFIN, R. C. 

C24 Development of Techniques for Mark III Implementation 

R. C. Coffin 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 124-127, November 30, 1970 

The implementation of the Deep Space Development Plan is 
resulting in significant changes in the Deep Space Network. This 
article describes the changes that are evident in packaging 
circuitry, and computer concepts. The new packaging technique 
characterized by the Mark III module, is designed to reflect the 
emphasis on integrated circuitry and printed circuit techniques 
In the area of circuitry, developments are being made to allow 
for the increased application of automatic control and checkout 
In addition to these "concrete" examples of new developments 
there are also changes occurring in the very concepts by which 
the equipment is designed. All new designs are being evaluated 
in light of increased use of computer control. 



COLLINS, R. J. 

C25 Surveyor Final Report— Lunar Theory and Processes: 
Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gault (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 
H. Masursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 



C26 Surveyor Final Report— Lunar Theory and Processes: 
Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 

of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 

R. A. Phinney (Princeton University), and E. M. Shoemaker (U.S. 

Geological Survey) 

icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

For abstract, see Gault, D. E. 



159 



COSTOGUE, E. N. 

C27 Electric Propulsion Power Conditioning 

[August-September 1970] 

E. N. Costogue 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 84-88, 
October 31, 1970 

The primary function of the electric propulsion power condition- 
ing system is to control the flow of power from the solar panel 
source to the ion thrusters to obtain high propellant utilization. 
To verify the power requirements of the hollow cathode ion 
thruster and to determine the control loop characteristics of the 
power conditioner, a task was initiated to modify an available 
breadboard power conditioner for an oxide cathode thruster con- 
figuration to operate with the hollow cathode thruster power 
requirements. The characteristics of the new supplies are pre- 
sented with a brief description of the circuit techniques employed. 



CRAWFORD, W. E. 

C28 Stepper Motor Drive Electronics for the Soiar Electric 

Thrust Vector Control Subsystem 

W. E. Crawford 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 108-110, 
December 31, 1970 

This article describes the design of a stepper motor drive elec- 
tronics. This work was done in conjunction with the design and 
construction of the solar electric thrust vector control system. 
Unique features of this stepper motor drive are discussed and a 
comparison with commercially available stepper motor drivers 
is made. 



CUDDIHY, E. F. 

C29 Superposition of Dynamic Mechanical Properties in the 
Glassy State 

E. F. Cuddihy and J. Moacanin 

Technical Report 32-1509 (Reprinted from J. Polyn). Sci., 
Pt. A-2: Polym. Phys., Vol. 8, No. 9, pp. 1627-1634, 
September 1970) 



160 



Superposition of the loss tangent curves could be achieved for 
the ,8-transition of a series of homologous epoxy resins. It was 
found that both a vertical and horizontal shift were necessary to 
achieve superposition when the curves were plotted as the 
logarithm of the loss tangent versus reciprocal absolute temper- 
ature. Resins from the diglycidyl ether of bisphenol A (DGEBA) 
were prepared with five different curing agents and their loss 
tangent curves measured on a free-oscillation torsion pendulum 
(ca. 1 cps). The /3 transition is caused by DGEBA, which was 
found via molecular models to contain a mobile group. The in- 
tensity of the loss for three of the resins was found to be pro- 
portional to the concentration of DGEBA, molecular models 
revealing that no additional mobile groups were introduced by 
these curatives. The remaining two curing agents introduced 
mobile groups into their systems, and, for these two, no separate 
transitions were identified but the intensity of the DGEBA p 
transition was increased. This may be caused by a coupling of 
the DGEBA mobile groups through the flexibility of the curative- 
introduced mobile groups. 

C30 On the Presence of Crystallinity in Hydrogenated 
Polybutadienes 

J. Moacanin, A. Eisenberg (McGill University, Canada), 
E. F. Cuddihy, D. D. Lawson, B. G. Moser (Moser Dental 
Manufacturing Company), and R. F. Landel 

Technical Report 32-1512 (Reprinted from J. App/. Po/ym. Sci., 
Vol. 14, No. 9, pp. 2416-2420, September 1970) 

For abstract, see Moacanin, J. 

C31 Investigation of Sterilizable Battery Separators 
[August-September 1970] 

E. F. Cuddiliy, D. E. Waimsley, J. Moacanin, and H. Y. Tom 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 171-176, 
October 31, 1970 

Graft copolymer membranes prepared by grafting poly(potas- 
sium acrylate) onto a thin film of crosslinked polyethylene are 
employed as separator membranes in sterilizable silver-zinc bat- 
teries. Changes that occur in the morphological state of the graft 
copolymer membrane resulting from exposure to the battery en- 
vironment were investigated using electron microscopy, electron 
microprobe analysis, and scanning electron microscopy. The ob- 
served results were then discussed and correlated with chemical 
changes that are known to occur in the membrane. 



161 



CUFFEL, R. F. 

C32 Changes in Heat Transfer From Turbulent Boundary Layers 
Interacting With Shock Waves and Expansion Waves 

L. H. Back and R. F. Cuffel 

AIAAJ., Vol. 8, No. 10, pp. 1871-1873, October 1970 

For abstract, see Back, L. H. 

C33 Relationship Between Temperature and Velocity Profiles in a 
Turbulent Boundary Layer Along a Supersonic Nozzle With 

Heat Transfer 

L. H. Back and R. F. Cuffel 

AIAA J., Vol. 8, No. 11, pp. 2066-2069, November 1970 

For abstract, see Back, L. H. 

CURKENDALL, D.W. 

C34 The Mariner VI and VII Flight Paths and Their Determination 

From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Mulier, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 

DACHEL, P. 

DOl RF Techniques: Superconducting Magnet for X-Band Maser 

R. Berwin and P. Dachel 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 45-47, 
October 31, 1970 

For abstract, see Berwin, R. 



DAMLAMAYAM, D. 

D02 Spacecraft Antenna Research: Antenna Tolerances 
D. Damlamayan 



162 



Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 43^9, 
December 31, 1970 

The effect of systematic and random errors on the gain of anten- 
nas representable by a field distribution over an aperture are 
discussed, with particular reference to reflectors and lenses. It is 
shown quantitatively that the manufacturing tolerances for lenses 
can be far less stringent than for reflectors. Indeed the easier tol- 
erances of lenses constitute their main advantage over reflectors. 



DeGENNARO, L 

DOS High-Speed Data/Wide-Band Data Input/Output Assembly 

R. Wengert, L. DeGennaro, and J. Mclnnis 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 133-136, November 30, 1970 

For abstract, see W^engert, R. 



DEO, N. 

D04 Extraction of Complete Subgraphs: Command Prefix 
Code for TOPS 

N. Deo 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 164-166, 
December 31, 1970 

Sandwiched between the idle sequence and the actual command 
words, a prefix word can be transmitted for synchronizing the 
command decoder aboard the spacecraft. Since the Thermo- 
electric Outer-Planet Spacecraft (TOPS) will have several com- 
mand decoders, it is important to obtain the largest set of 
mutually compatible prefix words of a specified length and 
specified error-correcting capability. Linear graph theory is used 
to solve this problem. The solution requires extraction of maxi- 
mal complete subgraphs out of a given graph. An algorithm for 
such extraction is sketched. Algorithms for connectedness of a 
graph and for identification of articulation points, as well as maxi- 
mally connected nonseparable blocks, serve as subalgorithms. 



DIEM, W. 

DOS Video Image Display Assembly 

W. Diem 

163 



The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 94-96, November 30, 1970 

The advent of imaging devices -on most spacecraft has led to 
the development of a Video Image Display Assembly by the 
Deep Space Network. This assembly will provide high quality 
tonal image displays and operational prints for real-time valida- 
tion and preliminary analysis of spacecraft pictures. A functional 
description of the assembly is presented. 

DONNELLY, H. 

D06 Block IV Receiver-Exciter Development 

H. Donnelly, A. C. Shallbetter, and R. E. Weiler 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 115-124, November 30, 1970 

The Block IV receiver-exciter is an automated subsystem de- 
signed to meet the future requirements of the Deep Space 
Network. This article gives a summary of the development of 
the engineering model of the Block IV, describing basic design 
goals and listing pertinent subsystem specifications. Photographs 
showing packaging techniques and the physical layout of the 
system are also included. 

DORE, M. A. 

D07 Neutron Yield From (a, n) Reaction With O^s Isotope 

M. Taherzadeh and M. A. Dore 

Supportirig Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 58-64, 
October 31, 1970 

For abstract, see Taherzadeh, M. 

DOWNS, G. S. 

DOS Observations of Interstellar Scintillations of Pulsar 
Signals at 2388 MHz 

G. S. Downs and P. E. Reichley 

Astrophys. J., Vol. 163, No. 1, Pt. 2, pp. L11-L16, 
January 1, 1971 

The scintillation index and fading time have been measured at 
2388 MHz. These measurements, together with low-frequency 
measurements, are interpreted in terms of the extended-medium 



164 



theory of Uscinski. Typically we find a scale size of electron 
irregularities of 4 X 10^° cm and an rms value of the electron den- 
sity fluctuations of 2 X 10"° cm-\ Failure to observe long-term 
variations suggests a second component of density fluctuations. 

DUXBURY, T. C. 

D09 The Mariner VI and VU Flight Paths and Their Determination 
From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 
For abstract, see Gordon, H. J. 

DIO Navigation Data From Mariner Mars 1969 TV Pictures 

T. C. Duxbury 

Navigation, Vol. 17, No. 3, pp. 219-225, Fall 1970 

As described in this article, a navigation experiment on the 1969 
Mariner mission to Mars used TV pictures of Mars in estimating 
the spacecraft trajectory. The lit limb of Mars was measured to 
determine the direction to the center of Mars in TV coordinates. 
The location of the center of Mars was determined to ~50 km 
(lo-) from the TV data. Additional processing of the TV data is 
expected to yield the center location to ~30 km (lo-). 

DWORNIK, S. E. 

Dll Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhieman (California 
institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of 
Hawaii), and A. L. Turkevich (University of Chicago") 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffe, L. D. 



165 



EISENBERG, A. 

EOl On the Presence of Crystallinity in Hydrogenated 

Polybutadienes 

J. Moacanin, A. Eisenberg (McGill University, Canada), 
E. F. Cuddihy, D. D. Lawson, B. G. iVloser (Moser Dental 
Manufacturing Company), and R. F. Landel 

Technical Report 32-1512 (Reprinted from J. Appl. Polym. Sci., 
Vol. 14, No. 9, pp. 2416-2420, September 1970) 

For abstract, see Moacanin, J. 



EISENBERGER, I. 

E02 Estimating the Parameter of an Exponential Distribution 

Using Quantiles 

1. Eisenberger 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. li, pp. 31-36, November 30, 1970 

This article presents the results of an investigation into the effects 
of a finite sample size on the bias and eiBciency of quantile 
estimators of the parameter of an exponential distribution, arising 
in Deep Space Instrumentation Facility wearout detection. These 
estimators were derived on the basis of the asymptotic normal 
distribution of the quantiles used. The exact moments of the 
quantiles and estimators are derived and computed for sample 
size n = 50, 100, and 200. Unbiased optimum or near-optimum 
estimators are also constructed using up to seven quantiles for 
these sample sizes. The results show that, even for moderate 
values of n, the bias of the asymptotic estimators are not 
excessive. 



ELLEMAN, D. D. 

EOS On the Relative Proton Affinity of Argon and Deuterium 

M. T. Bowers (University of California, Santa Barbara) and 
D. D. Eileman 

J. Am. Chem. Soc, Vol. 92, No. 25, pp. 7258-7262, 

December 16, 1970 

For abstract, see Bowers, M. T. 



166 



ERICKSON, D. 

E04 DSN Progress Report for November-December 1970: 

Concatenation of Short Constraint Length Convolutional Codes 

D. Erickson 

Technical Report 32-1526, Vol. I, pp. 46-51, February 15, 1971 

Several methods of decoding a concatenated pair of K = 6, 
V = 2 convolutional codes are investigated. It was found tliat 
none of the methods provides performance which is suitable for 
space channel application. 

ESTABROOK, F. B. 

EOS Solution of Partial Differential Systems 

F. B. Estabrook, B. K. Harrison (Brigham Young University), 
and H. D. Wahlquist 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, p. 17, 
December 31, 1970 

This article summarizes a new method that has been found for 
obtaining various kinds of special solutions of sets of nonlinear 
partial differential equations. It has been applied to representa- 
tive sets of equations in fluid physics, plasma physics, and 
general relativitv. 



EVANS, R. H. 

E06 High-Speed Data Block Demultiplexer 

R. H. Evans 

Tfie Deep Space Netvfork, Space Programs Summary 37-66, 
Vol. II, pp. 105-106, November 30, 1970 

This article presents a functional description of the block demul- 
tiplexer (BDXR). The BDXR will be used in the Deep Space 
Network Ground Communications Facility (GCF) Deep Space 
Station Communications Equipment Subsystem to provide a new 
interface between the receiving circuit of one high-speed-data 
channel and a maximum of six on-station computers (OSCs). 
The BDXR will examine the OSC destination codes of each data 
block and transfer only those blocks properly addressed to any 
combination up to six OSCs. The BDXR application will mini- 
mize the OSC machine loading for the receive data function, and 
the GCF High-Speed-Data System function of transferring data 
blocks from source to sink is precisely performed. 



167 



FERRERA, J. D. 

FOl TOPS Attitude-Control Single-Axis Simulator 

J. D. Ferrera and G. S. Perkins 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 118-119, 
October 31, 1970 

This article describes the configuration of the single-axis simu- 
lator which will be used to provide a breadboard hardware veri- 
fication of the present Thermoelectric Outer-Planet Spacecraft 
(TOPS) baseline attitude-control system. The gas bearing and 
table are detailed with preliminary information on the systems 
which will be mounted on the table. 



FINNIE, C. 

F02 DSN Progress Report for November-December 1970: 

Frequency Generation and Control: Atomic Hydrogen Maser 
Frequency Standard 

C. Finnic 

Technical Report 32-1526, Vol. I, pp. 73-75, 
February 15, 1971 

System considerations are desczibed for a prototype hydrogen 
maser cavity tuner for use with the atomic hydrogen maser 
frequency standard developed at the Jet Propulsion Laboratory. 
The tuner system and the tuner operation sequence are illustrated. 



FISHER, J. G. 

F03 Mesh Materials for Deployable Antennas 

J. G. Fisher 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 122-125, 
October 31, 1970 

Evaluation of mesh materials for deployable antennas continues. 
The results of RF testing of Paliney 7, a precious metal alloy, as 
a substitute for Chromel R are given, with a preliminary value 
for its solar-absorptance-to-emittance ratio. A description is in- 
cluded of equipment developed to evaluate the elastic character- 
istics of mesh materials at various temperatures, along with 
representative curves derived from its use. 



168 



F04 Development of a Conical-Gregorian Higli-Gain Antenna 
J. G. Fisher 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. ill, pp. 118-119, 
December 31, 1970 

Continued development of the conical-Gregorian antenna con- 
cept is described. A furlable 6-ft-diameter model utilizing a 
0.020-in.-thick 2024-T3 aluminum alloy sheet as the reflective 
surface was constructed. Problems associated with the design, 
fabrication, and testing of this model are discussed, as well as 
plans for continued development in the direction of compliant 
reflective surfaces supported by stifE but furlable members. Results 
of preliminary tests to evaluate materials and design details for 
this concept are included. 

FLIEGEL, H. F. 

F05 Polar Motion: Doppier Determinations Using Satellites 
Compared to Optical Results 

C. C.Chaoand H. F. Fliegel 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. 11, pp. 23-26, November 30, 1970 

For abstract, see Chao, C. C. 

FREILEY, A. J. 

F06 DSN Progress Report for November-December 1970: Tracking 
and Data Acquisition Elements Research: Polarization 
Diverse S-Band Feed Cone 

D. E. Neff and A. J. Freiley 

Technical Report 32-1526, Vol. I, pp. 66-72, 
February 15, 1971 

For abstract, see Neff, D. E. 



GALE, G. 

GOl Hydrostatic Bearing Runner Level Reference 

G. Gale and H. Phillips 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. 11, pp. 80-83, November 30, 1970 

This article describes a method used to survey a 70-ft-diameter 
circle, which is used as an elevation reference for surveying the 



169 



210-ft-diameter antenna hydrostatic bearing runner at DSS 14 
(Mars Deep Space Station). The surface surveyed, and then 
used as an intermediate height reference, is the top of the 
azimuth drive bull gear, which is set on the antenna concrete 
pedestal. The center of the circle is shielded from the reference 
circle so that conventional optical methods are not applicable. 
The method described gives a probable error in elevation of less 
than 0.001 in. 



GARSIA, A. M. 

G02 A Real Variable Lemma and the Continuity of Paths of 

Some Gaussian Processes 

A. M. Garsia, E. Rodemich, and H. Rumsey, Jr. 

Ind. Univ. Math. J., Vol. 20, No. 6, pp. 565-578, 
December 1970 

The now standard method of constructing a separable and 
measurable model for a mean continuous stochastic process, 
starting from a given consistent system of joint distributions, 
although somewhat arbitrary, is perhaps unavoidable in the gen- 
eral case. However, a more direct approach that is frequently 
used by communications engineers in the gaussian case is to 
expand the paths in terms of the eigenfunctions of the covariance 
kernel. The resulting expression, which is usually referred to as 
the Karhunen-Loeve expansion and was apparently introduced 
quite early by M. Kac, is a very natural tool to use. 

The purpose of this article is to show that, at least in the cases 
when the paths are known to be almost surely continuous, this 
procedure can indeed be used to produce the desired models. In 
fact, it is shown that the best possible estimates for the modulus 
of continuity of the sample paths can be directly obtained from 
a study of the partial sums of this expansion. 

The main tool here is a real variable lemma whose significance 
will, perhaps, transcend the applications that have led to its dis- 
covery. This is a lemma which, roughly speaking, states that the 
finiteness of a certain integral involving a given function has a 
bearing on the modulus of continuity of such a function. Results 
of similar nature have appeared in Fourier analysis and partial 
differential equations, but, as far as the authors know, no result 
of the generality of this lemma has appeared in the literature 
before. The power of the lemma lies in the fact that it provides 
a step which enables the user to pass from global estimates, often 
readily available in a probabilistic setting, to local estimates, 
which usually appear to be of a more elusive nature. 



170 



GARSTANG, R. H. 

G03 Transition Probabilities for Xe 1 

C. J. Chen and R. H. Garstang (University of Colorado) 

J. Quant. Spectrosc. Radiat Transfer, Vol. 10, No. 12, 
pp. 1347-1348, December 1970 

For abstract, see Chen, C. J. 



GARTHWAITE, K. 

G04 A Preliminary Special Perturbation Theory 
for the Lunar Motion 

K. Garthwaite, D. B. Holdridge, and J. D. Mulholland 

Technical Report 32-1517 (Reprinted from Astron. J., 
Vol. 75, No. 10, pp. 1133-1139, December 1970) 

A combination of literal and numerical integration techniques 
has been used to produce a lunar ephemeris more adequate for 
high-precision applications than has heretofore been available. 
The numerical integration was differentially fitted to source posi- 
tions computed from a reduced theory at half-day intervals over 
a 20-yr span, a process intended to eliminate the gravitational 
defect in the literal theory. Spectral analysis of the residuals 
confirms the earlier conjecture that this defect is a truncation 
effect in the planetary perturbation terms of the theory. Compari- 
son of the final ephemeris with transit circle observations shows 
a small systematic effect in right ascension and the previously 
known bias in declination, but the standard deviation is less than 
0.8 arc sec for each coordinate. Comparison with a few prelimi- 
nary laser range observations shows residuals of the order of 
100 m. 



GAULT, D. E. 

G05 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langiey Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of 
Hawaii), and A. L. Turkevich (University of Chicago) 



171 



Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffa, L. D. 

G06 Surveyor Final Report— Lunar Theory and Processes; 
Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gauit (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 
H. Masursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 

G07 Sorveyor Final Report— Lunar Theory and Processes: 
Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 
of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 
R. A. Phinney (Princeton University), and 

E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

Observations of the western horizon shortly after sunset during 
the Surveyor VII mission revealed, along the crest of the horizon, 
a bright line of light similar to that previously reported for the 
Surveyor V and VI missions. Though not sufficiently well-defined 
to be recognized at the time, the phenomenon also occurred dur- 
ing the Surveyor I mission. Although no sunset observations were 
made on Surveyor III, it appears that this postsunset phenom- 
enon along the western horizon (and probably the eastern horizon 
at sunrise) is not an unusual event, but occurs regularly as the 
natural consequence of some aspect of the lunar environment. A 
discussion of the phenomenon is presented here. 



GAYMAN, W. H. 

G08 Equivalent Spring-Mass System for Normal Modes 
R. M. Bamford, B. K. Wada, and W. H. Gayman 
Technical Memorandum 33-380, February 15, 1971 
For abstract, see Bamford, R. M. 

172 



GOLD, T. 

G09 Surveyor Final Report— Lunar Theory and Processes: 
Chemical Observations by Surveyor V 

T. Gold (Cornell University) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 224-225, 
March 1970 

The important observation that the lunar soil at the Surveyor V 
landing site is basaltic in composition is taken by many to sub- 
stantiate the viewpoint, previously widespread, that volcanism 
formed most of the lunar surface, supplying a differentiated type 
of rock. The case for this is, however, by no means so simple or 
so clearcut. The arguments previously voiced against a wide- 
spread differentiation on the moon are now just as strong, or in 
some cases even strengthened, by recent observations. This con- 
troversy is briefly discussed in this article. 



GIO Surveyor Final Report— Lunar Theory and Processes: 
The Physical Condition of the Lunar Surface 

T. Gold (Cornell University) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 226-229, 
March 1970 

The five successful Surveyor soft landings demonstrated that the 
lunar surface is composed, in general, or very fine, slightly co- 
hesive rock powder. The depth of this material, the particle size, 
and the ubiquity of this type of surface can still be debated; but 
very significant constraints can be placed on each. This article 
describes the Surveyor results pertinent to the physical condition 
of the lunar surface, particularly the observed spray phenomena. 
A discussion is included on the importance of the results for 
future lunar technology. 



GORDON, H. J. 

Gl 1 The Mariner VI and VI! Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Mulier, C. C. Chao, B. D. Mulhali, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 



173 



This report describes the current best estimate of the Mariner VI 
and VII flight paths and the way in which they were determined 
using Deep Space Instrumentation FaciHty tracking data. The 
flight paths are separated into three phases: (1) launch to 
maneuver or pre-maneuver phase, (2) cruise or post-maneuver 
phase, and (3) encounter phase. Discussions of the Precision Navi- 
gation Project, flight operations, maneuver analyses, and optical 
observables are included. 



GOSS, W. C. 

G12 TOPS Attitude-Control Single-Axis Simulator 
True Position Encoder 

W. C. Gossand L.S.Smith 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 119-121, 
October 31, 1970 

The Thermoelectric Outer-Planet Spacecraft (TOPS) single-axis 
simulator is being built upon a gas-bearing table as a test bed for 
future attitude-control systems. To evaluate the attitude-control 
system performance, a frictionless technique of monitoring the 
positional activity of the test bed was developed. This article 
describes the true position encoder developed and its functional 
characteristics. Performance tests demonstrating the achievement 
of 0.01-deg angular accuracy over a full 360-deg rotation are 
presented. 



HABBAL, N. 

HOI SFOF IBM 350/75 User Device Switching Assemblies 

N. Habbal 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 75-77, November 30, 1970 

Two IBM 360/75 computers are installed in the Space Flight 
Operations Facility (SFOF). Either computer may be used for 
real-time mission support while the other is used for off-line 
processing or as backup to the real-time computer. To gain 
maximum flexibility and economy, a switching system has been 
developed to provide switching of user input/output devices 
such as cathode-ray tube displays, card readers, and line printers. 
These switching assemblies, which form part of the real-time 
input/output interface subsystem, are described in this article. 



174 



HADEK, V. 

H02 Energy Transfer in Bipyridilium (Paraquat) Salts 

A. Rembaum, V. Hadek, and S. P. S. Yen 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 189-191, 
December 31, 1970 

For abstract, see Rembaum, A. 



HOB Electrical Properties of TCNQ Salts of lonene Polymers 
and Their Mode! Compounds 

V. Hadek, H. Noguchi, and A. Rembaum 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 192-198, 
December 31, 1970 

Electrically conducting polysalts were prepared by the reaction 
of ionene polymers with LiTCNQ in presence or in absence of 
neutral TCNQ. The specific resistivity, the activation energy for 
conductivity, and the Seebeck coefficient were determined as a 
function of the number of CH, group between positively charged 
nitrogens. The wide variations of electrical properties could not 
be correlated with the length of the polymethylene chain in the 
polymer. X-ray analysis of single crystals of model compounds 
revealed that the electrical properties depend mainly on crystal 
geometry. 



HAMILTON, T. W. 

H04 DSN Progress Report for November-December 1970: DSN 
Inherent Accuracy Project 

T. W. Hamilton and D. W. Trask 

Technical Report 32-1526, Vol. I, pp. 1 1-13, 
February 15, 1971 

The Deep Space Network (DSN) Inherent Accuracy Project was 
formally established in July 1965 to: (1) determine (and verify) 
the inherent accuracy of the DSN as a radio navigation instru- 
ment for lunar and planetary missions, and (2) formulate designs 
and plans for refining this accuracy to its practical limits. The 
organization of the project and the current technical work per- 
formed are summarized in this article. 



175 



HAND, P. J. 

H05 Digital Gyro System (Phase I) 

P.J. Hand 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 105-107, 

December 31, 1970 

A complete, self-contained, single-axis, digital gyro system has 
been developed and built for use with the Thermoelectric Outer- 
Planet Spacecraft single-axis attitude-control system simulator. 
The gyro system has been under test for more than one month 
and has accumulated over 900 h of operational time. Measured 
performance is shown by two charts of long- and short-term drift 
rate and of pulse scale factor calibration stabiUty. 



HANSELMAN, R. 

H06 Wideband Digital Data System Terminal Configuration 

R. Hanselman 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 107-110, November 30, 1970 

This article covers the specific configuration of each of the 
terminals involved in the data portion of the Deep Space Net- 
work Ground Communications Facility 1971-1972 Wideband 
System. A description of each of the major equipments used in 
the system is also covered. This article is an amplification of a 
previous article on this subject earlier in this SPS series. 

HANSON, R. B. 

H07 Soil iWicrobiai and Ecological Investigations in 

the Antarctic Interior 

R. E. Cameron, R. B. Hanson, G. H. Lacy, and F. A. Morelli 
Antarc. J. U.S., Vol. V, No. 4, pp. 87-88, July-August 1970 
For abstract, see Cameron, R. E. 

H08 Microbiological Analyses of Snow and Air From 
the Antarctic Interior 

G. H. Lacy, R. E. Cameron, R. B. Hanson, and F. A. Morelli 

Anfarc. J. U.S., Vol. V, No. 4, pp. 88-89, July-August 1970 

For abstract, see Lacy, G. H. 



175 



HANSON, R. J. 

H09 Automatic Error Bounds for Real Roots of Polynomials 
Having Interval Coefficients 

R. J. Hanson 

Technical Report 32-1497 (Reprinted from Comput J., 
Vol. 13, No. 3, pp. 284-288, August 1970) 

A generalized Newton-Raphson method for use with interval 
arithmetic is described. This algorithm can, for example, be used 
with great effectiveness to obtain precise bounds for the real 
roots of real polynomials whose coefficients are not exactly 
known. Two eigenvalue problems for real matrices are given as 
examples. 

HIO Unitary Similarity Transformation of a Hermitian 
Matrix to a Real Symmetric Tridiagonal Matrix 

R. J. Hanson 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 10-12, 
December 31, 1970 

The details necessary for transforming a general complex her- 
mitian matrix to real tridiagonal form are given. To accomplish 
this. Householder unitary transformations are used primarily. 
Some computational points are also presented which can be used 
to decrease the amount of computer storage and time. 



HARPER, L 

Hll DSIF Integrated-Circuit Layout and ^soperimetric Problems 

L Harper 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. 11, pp. 37-42, November 30, 1970 

This article shows how to lay out 16 integrated circuits for the 
maximum-likelihood convolutional decoder on a linear card so 
that the total length of connecting wires is mimimized. The 
methods used can be applied to any circuit diagram of reasonable 
size, since all calculations were done by hand using special 
properties of the graph of the circuit. In general, growth of the 
calculations is exponential with the number of circuits, but the 
particular graphs that arise in the Deep Space Instrumentation 
Facility (DSIF) subsystems usually have properties such as sym- 
metries or regularity which allow great simplification by ad hoc 



177 



means. The methods are extended to rectangular cards, and can 
be extended to higher dimensions in an obvious way. The prob- 
lem of minimizing the maximal length of a connecting wire is 
also considered, and areas for further research are suggested. 



HARRISON, B. K. 

H12 Solution of Partial Differential Systems 

F. B. Estabrook, B. K. Harrison (Brigham Young University), 
and H. D. Wahlquist 

Supporting Research and Advanced Developnnent, 
Space Programs Summary 37-66, Vol. Ill, p. 17, 
December 31, 1970 

For abstract, see Estabrook, F. B. 



HASBACH, W. A. 

H13 Lightweight Solar Panel Development 

[August-September 1970] 

W. A. Hasbach 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 73-80, 
October 31, 1970 

The design, analysis, fabrication, and testing of a lightweight 
solar panel made of built-up beryllium structure with an active 
solar cell area of 29 ft- are described. Testing included modal 
survey, reverberant acoustic, random vibration, sinusoidal vibra- 
tion, static load, thermal-vacuum-shock, substrate frequency 
check, and power output tests. The design goal of 20-W/lb spe- 
cific power output was achieved. 



HAUDENSCHILD, C. 

H14 Mufti-Phase Ammonia Water System (Rev. 1) 

C. Haudenschild 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 4-9, 
December 31, 1970 

Equations are fitted to tabular laboratory data available for 
ammonia water systems. The equations relate temperature, con- 
centration, and partial pressures over solution, solid hydrate, solid 



178 



water, and solid ammonia. The freezing curve, in the form of 
an equation for temperature as a function of concentration, is 
given for the phase boundary of each region. Finally, a phase 
diagram displaying all equations is produced. This article is a 
revision of that appearing in Space Programs Summary 37-64, 
Vol. Ill, and includes changes in tabular data. 



HEER, E. 

H15 VISCEL— A General-Purpose Computer Program for Analysis 
of Linear Viscoelastic Structures: User's Manual 

F. A. Akyuz and E. Heer 

Technical Memorandum 33-466, Vol. I, February 15, 1971 

For abstract, see Akyuz, F. A. 

H15 Optimum Pressure Vessel Design Based on Fracture 
Rrtechanics and Reliability Criteria 

E. Heer and J.-N. Yang 

Technical Memorandum 33-470, February 1, 1970 

Spacecraft structural systems and subsystems are subjected to a 
number of qualification tests in vsrhich the proof loads are chosen 
at some level above the simulated loads expected during the 
space mission. Assuming fracture to be the prime failure mech- 
anism, and allowing for time effects due to cyclic and sustained 
loadings, this memorandum treats an optimization method in 
which the statistical variability of loads and material properties 
are taken into account, and in which the proof load level is used 
as an additional design variable. In the optimization process, the 
structural weight is the objective function, while the total ex- 
pected cost due to coupon testing for material characterization, 
failure during proof testing, and mission degradation is a con- 
straint. Numerical results indicate that, for a given expected cost 
constraint, substantial weight savings and improvements in reli- 
ability can be realized by proof testing. 

H17 Optimization of Space Antenna Structures 
E. Heer and J.-N. Yang 
Technical Memorandum 33-472, March 15, 1971 

This memorandum develops an optimization scheme that can 
readily be applied to the optimum design of space antennas, as 



179 



well as to the evaluation and comparison of antenna concepts, 
antenna structural types, and antenna structural materials. The 
objective function is either cost or weight; the design variables 
are diameter, weight per imit area, manufacturing precision 
measure, and sizes of structural elements. With system require- 
ments such as antenna gains, communication frequencies, etc., as 
constraints, the objective function is minimized with respect to 
the design variables. Through this optimization process, it can be 
demonstrated whether the effort of improving a particular tech- 
nology, such as manufacturing, has advantages under certain 
operational requirements. 

H18 Reliability of Randomly Excited Structures 

J.-N. Yang and E. Heer 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 128-136, 
December 31, 1970 

For abstract, see Yang, J.-N. 



HOFFMAN, J. K. 

H 19 Evaluation of Spacecraft Magnetic Recording Tapes and 
Magnetic Heads [August-September 1970] 

S. H. Kalfayan, R. H. Silver, and J. K. Hoffman 

Supporting Research and Advanced Developnnent, 
Space Programs Summary 37-65, Vol. Ill, pp. 168-171, 
October 31, 1970 

For abstract, see Kalfayan, S. H. 



H20 Evaluation of Recording Tape and Heads for 

Spacecraft Magnetic Tape Recorder Applications 

[October-November 1970] 

J. K. Hoffman, S. H. Kalfayan, and R. H. Silver 

Supporting Research and Advanced Developnnent, 
Space Programs Summary 37-66, Vol. Ill, p. 160, 
Decembers!, 1970 

Phase III of a study of the characteristics of magnetic recording 
tapes and the tape-to-head interface in the spacecraft environ- 
ment was completed. This article briefly describes the work, but 
gives no results. 



180 



H21 Evaluation of Magnetic Recording Tapes: A Method for the 
Quantitative Determination of Stick-Slip 

R. H. Silver, S. H. Kalfayan, and J. K. Hoffman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 198-200, 
December 31, 1970 

For abstract, see Silver, R. H. 



HOLDRIDGE, D. B. 

H22 A Preliminary Special Perturbation Theory 
for the Lunar Motion 

K. Garthwaite, D. B. Holdridge, and J. D. Mulholland 

Technical Report 32-1517 (Reprinted from Asfron. J., 
Vol. 75, No. 10, pp. 1133-1139, December 1970) 

For abstract, see Garthwaite, K. 



HOLMES, J. 

H23 Decoding and Synchronization Research: A Note on the 

Optimality of the All-Digital Command System Timing Loop 

J. Holmes 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 19-21, 
October 31, 1970 

A more general sampling geometry is investigated for the timing 
update portion of the all-digital, single-channel, command system 
that has been developed as part of the Thermoelectric Outer- 
Planet Spacecraft Project. With the existing threshold of 2.2 dB, 
it is shown that the optimum sampling geometry, constrained to 
16 equally spaced samples per cycle, is the existing single-sample 
procedure. 



HOPPER, E. T. 

H24 Ion Thruster Connectors 

E. T. Hopper 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Hi, pp. 211-212, 
December 31, 1970 



181 



A commercially available connector has been modified for use 
in an ion thruster system. Modifications permit use in vacuum 
of a single connector for leads v^^ith voltage differentials up to 
3000 V without arc-over or detectable leakage. This connector 
appears suitable for flight application. 



HORTON, T. E. 

H25 Shock-Tube Thermochemistry Tables for 

High-Temperature Gases: Nitrogen 

W. A. Menard and T. E. Horton 

Technicai Report 32-1408, Vol. IV, December 1, 1970 

For abstract, see Menard, W. A. 

HULTBERG, J.A. 

H26 Thermal Analysis System 1: User's Manual 

J. A. Hultberg and P. F. O'Brien 

Technical Report 32-1416, March 1, 1971 

A computer program (Thermal Analysis System I) was written to 
calculate steady-state temperatures for a radiation-conduction- 
coupled constant-property thermal model. A two-region spectral 
analysis is provided for the radiation portion of the computation. 
The "script £?" technique is used for infrared heat transfer, and 
the radiosity technique is used for solar heat input. The program 
is designed for maximum ease of use from the user's standpoint. 
The rules for order and placement of user input data to the pro- 
gram are almost free-form. The output is formatted for ease of 
user understanding and diagnosis of errors. Some user control of 
output is provided. 



HURD.W.J. 

H27 Digital Clean-Up Loop Transponder for Sequential 

Ranging System 

W. J. Hurd 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 18-27, 
December 31, 1970 



182 



The theory, implementation, and experimental performance of 
an improved ranging transponder for sequential component rang- 
ing systems are presented. The new transponder system, called 
a clean-up loop, regenerates the ranging signal from the signal 
plus noise at the spacecraft receiver so that only signal and not 
receiver noise is transmitted on the downlink. The improvement 
in downlink signal-to-noise ratio afforded by this system is up to 
46 dB in the present model, with further improvement possible. 
This will enable accurate ranging at distances of 31 AU using a 
low-gain spacecraft antenna, and could solve the uplink noise 
problem for ranging a solar electric multi-mission spacecraft at 
closer distances. 



H28 Performance of a Phase-Locked Loop During Loss of Signal 

W. J. Hurd 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 28-32, 
December 31, 1970 

When a phase-locked loop (PLL) is tracking the phase of a signal 
in noise, and the signal is suddenly removed, the phase error vari- 
ance increases with time after loss of signal. This article derives 
the statistics of the N state variables for an Nth order PLL as a 
function of time after loss of signal. A specific result is that for 
first-order loops with no frequency offset and for perfect integra- 
tor second-order loops, the rms phase error doubles in about 
OA/bi, seconds after loss of signal, where &l is the one-sided loop 
bandwidth in hertz. 



JACKSON, E. B. 

JOl DSS 13 Operations 

E. B. Jackson 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, p. 89, November 30, 1970 

Operations at DSS 13 (Venus Deep Space Station) are reported 
for the period August 16 through October 15, 1970. During this 
period, the station maintained a reduced schedule of clock syn- 
chronization transmissions, continued its support of the program 
of pulsar observations, participated in cooperative planetary radar 
experiments with DSS 14 (Mars DSS), and continued develop- 
ment of the Ephemeris Offset Tracking Program. Major main- 
tenance performed on the 1.2-MW, 400-Hz motor-generator set 
and progress on the FIRE-X program are also reported. 



183 



JAFFE, L D. 

J02 Surveyor Final Reports— Introduction 

L. D. Jaffa and R. H. Steinbacher 

Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 145-155, 
March 1970 

This article introduces a series of articles in this issue that review 
and summarize preliminary Surveyor findings, compare the re- 
sults from each mission, and, in some cases, give results of 
analyses made after the publication of the preliminary mission 
reports issued just subsequent to the end of each mission. Those 
spacecraft characteristics most necessary to an understanding of 
the scientific data obtained and the corresponding characteristics 
of spacecraft operations are discussed here. 

JOS Surveyor Final Report— Principal Scientific Results 
From the Surveyor Program 

L. D. Jaffa, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langlay Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gauit (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

The successful soft landings made by five Surveyor spacecraft 
permitted detailed examinations of the lunar surface at four mare 
sites along an equatorial belt and at one highland site in the 
southern hemisphere. The aiming areas, selected before launch, 
were chosen after examination of telescopic and Lunar Orbiter 
photographs (except for the Surveyor I mission, which preceded 
the Lunar Orbiter flights). All five spacecraft landed within these 
selected areas. The landing sites were: 

Surveyor L Flat surface inside a 100-km crater in Oceanus Pro- 
cellarum, 1 radius from the edge of a rimless 200-m crater. 

Surveyor 111. Interior of a subdued 20O-m crater, probably of 
impact origin, in Oceanus Procellarum. 

Surveyor V. Steep, inner slope of a 9- by 12-m crater, which 
may be a subsidence feature, in Mare Tranquillitatis. 

Surveyor V7. Flat surface near a mare ridge in Sinus Medii. 



184 



Surveyor VII. Ejecta or flow blanket north of, and less than 1 
radius from, the rim of the crater Tycho in the highlands. 

The small craters; resolvable rock fragments; particle size; struc- 
ture and mechanical behavior of the fine material; optical, ther- 
mal, and radar characteristics; and chemical composition for 
these landing sites are described here. Observations of the earth 
and of the solar corona are also discussed. 



J04 Lunar Surface: Changes in 31 Months and Micrometeoroid Flux 
L. D. Jaffa 

Science, Vol. 170, No. 3962, pp. 1092-1094, 
December 4, 1970 

Comparison of pictures of the lunar surface taken 31 mo apart 
by Surveyor III and Apollo 12 show only one change in the areas 
disturbed by Surveyor: a 2-mm particle, in a footpad imprint, that 
may have fallen in from the rim or been kicked in by an ap- 
proaching astronaut. Vertical walls 6 cm high did not collapse, 
and dark ejecta remained dark. No meteorite craters as large as 
1.5 mm in diameter were seen on a smooth soil surface 20 cm 
in diameter; this indicates a micrometeoroid flux lower than 
4 X 10"'^ micrometeoroids/m--s at an energy equivalent to about 
3 X 10"** g at 20 km/s. This flux is near the lower limit of pre- 
vious determinations. 



JAWORSKI, W. 

JOS Manner Venus-Mercury 1973 Solar Array Components: 
500-h Irradiation Test Results 

W. Jaworski 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 125-131, 
October 31, 1970 

Test results of the 500-h irradiation of Mariner Venus-Mercury 
1973 solar array components are briefly described. Three identi- 
cal groups of samples (6 samples in each) have been subjected to 
testing in the vacuum chamber at 5 X lO"' torr. A different type 
of irradiation was applied to each group: ultraviolet, proton, and 
simultaneous ultraviolet and proton. The fluxes and energy were 
those likely to be present in the vicinity of Mercury; sample 
temperature was 140 °C (maximum allowable). 

The optical measurements of solar reflectance, transmittance, and 
absorptance do not indicate significant changes caused by the 



185 



irradiation applied; however, some components sustained me- 
chanical damage due to possible thermal incompatibility. 

JOS Cracking of Filter Layers in a High Performance Solar Cell Filter 

W. Jaworski 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 115-117, 

December 31, 1970 

The incident of cracking of the filter layers in a high performance 
filter cover for solar cells (modified 4026 filter) has been investi- 
gated, and the results are evaluated and discussed. It appears that 
a probable cause of cracking was a combined effect of induced 
manufacturing stresses and elevated temperature during the test. 
There is some evidence to believe that if these manufactxiring 
stresses were absent, this type of filter could perform satisfac- 
torily, and would be suitable for solar arrays designed for the 
near-sun missions at about 0.5 AU. 



JET PROPULSION LABORATORY 

J07 Mariner Mars 1969 Project Report: Performance 

Jet Propulsion Laboratory 

Technical Report 32-1460, Vol. II, March 1, 1971 

This second of three volumes of the Mariner Mars 1969 Project 
Report describes the performance of the mission by flight and 
Earth-based elements during the launch and space flight phases. 
The first volume describes the pre-operational activities, includ- 
ing planning, development and design, manufacture, and testing; 
the third volume deals with the scientific program, including 
experiment results. 

The dual-spacecraft (Mariners VI and VII) Mars flyby mission 
was successfully conducted according to plan. A number of flight 
anomalies were observed, including a major incident involving 
the Mariner VII spacecraft shortly before its Mars encounter, but 
these difficulties were overcome. The performance of all elements 
was generally excellent, and copious scientific data were returned 
to the Earth, including television pictures, ultraviolet and infra- 
red spectral data, surface-temperature measurements, and other 
information. 

The flight performance of each element is analyzed, problems 
are discussed, and recommendations based on the experience 
are presented. 



186 



JET PROPULSION LABORATORY: 
ASTRIONICS DIVISION 

JOS Manner Mars 1971: Astrionics [September-October 1970] 

Jet Propulsion Laboratory: Astrionics Division 

Flight Projects, Space Programs Summary 37-56, Vol I, 
pp. 9-12, November 30, 1970 

Although the concept of a peripheral belt drive had been proven 
feasible prior to its selection for the Mariner Mars 1971 tape 
transporter, it had not been adequately mathematically modeled 
to achieve a thorough understanding of the mechanism. When 
stick-slip (random incremental tape velocity) occurred at the tape- 
to-head interface early in the developmental stages of the project, 
a thorough understanding of the tape tension, tension variation, 
and mechanism for developing tape tension became inperative. 
A rigorous analytical model of the transport drive u'as devel- 
oped. The quasistatic analysis was used to develop an expression 
for take-up tension as a function of: (1) pay-out tape tension, 
(2) deck reel and idler geometry, (3) static force and moment 
equilibrium, (4) belt and tape elasticity, (5) magnetic head drag, 
(6) tape length, and (7) the relationships between belt thick- 
ness and tape thickness. The analytical model and the conclusions 
reached are described in this article. 

J09 Viking, Orbiter System: Astrionics [September-October 1970] 

Jet Propulsion Laboratory: Astrionics Division 

Flight Projects, Space Programs Summary 37-65, Vol. I, 
pp. 53-55, November 30, 1970 

The Mariner engineering data formats were fixed in both length 
and content. A flight data subsystem using a reprogrammable 
data format would enable more efficient usage of the data link 
during the Viking missions, since the option would be available 
to program various subsets of the total telemetry measurement 
list into the format when they are needed and to program them 
out of the format at other times. Such a system is described in 
this article. 

JET PROPULSION LABORATORY: 
DATA SYSTEMS DIVISION 

JIO Mariner Mars 1971: Data Systems [September-October 1970] 

Jet Propulsion Laboratory: Data Systems Division 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 3-4, November 30, 1970 



187 



The mission and test computer system completed the real-time 
support of the Mariner Mars 1971 proof-test-model system tests 
using a data system based on a single Univac 1219 computer. A 
second data input subsystem,- telemetry assemblers, and remote 
and local serial interface equipment for intercommunication with 
display equipment were added to the hardware in order to pro- 
vide for the simultaneous testing of two flight spacecraft, which 
began in late-September. A Univac 1219 computer was assigned 
to each spacecraft for this test phase. By mid-October, sufficient 
programming development was completed to begin using the 
Univac 1230 computer and the two Univac 1219 computers in 
an integrated three-computer system configuration. Activities 
related to the test phases and the initial use of the new configura- 
tion are described in this article. 

JET PROPULSION LABORATORY: 
ENGINEERING MECHANICS DIVISION 

Jll Mariner Mars 1971: Engineering !\flechanics 

[September-October 1970] 

Jet Propulsion Laboratory: Engineering iVIechanics Division 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 21-30, November 30, 1970 

Some or all of a spacecraft's mass properties must be known in 
order to perform launch vehicle performance calculations, space- 
craft aV capabihty calculations, autopilot stability and perfor- 
mance analyses, attitude-control gas consumption estimates, and 
spacecraft/launch-vehicle separation analyses. The analytical 
and measurement activities to determine the mass properties for 
the Mariner Mars 1971 spacecraft are described, and the meas- 
ured and calculated values are tabulated. 

The second discussion involves an evaluation of the capability 
of the peak select acceleration control system. This evaluation 
was necessitated by dynamic test implementation problems 
encountered during forced vibration testing of the propulsion 
module. The particular phase of the evaluation that is described 
was performed with the aid of an analog computer that simulated 
the dynamic characteristics of the propulsion module and vibra- 
tion exciter and the vibration exciter and amplifier electrical 
characteristics. The uniqueness of the evaluation was the com- 
bination of the real-time analog simulation of the test structure 
and shaker system with the actual test control system. 

An evaluation was also made of the codispersion propellant 
expulsion bladder. This bladder is a flexible TFE-FEP Teflon 
laminate membrane that fits inside a 30-in.-diameter titanium 



ISS 



propellant tank and is pressurized by nitrogen to expel pro- 
pellants contained therein under 0-g conditions. This article 
summarizes some significant test results on the codispersion ma- 
terial derived prior to production of flight bladders of this type. 

The final discussion involves an evaluation of the spacer rod 
material for the spring-loaded spacer system employed by the 
narrow-angle television camera to maintain dimensional require- 
ments between critical optical elements. The tests were made on 
random samples to verify material requirements and to obtain 
property data. 

J 12 Viking, Orbiter System: Engineering Mechanics 
[September-October 1970] 

Jet Propulsion Laboratory: Engineering iVlechanics Division 

Flight Projects, Space Programs Sumnnary 37-66, Vol. I, 
pp. 51-52, November 30, 1970 

This article discusses the Viking-spacecvait/ Centaur adapter and 
the orbiter/lander adapter separation interfaces. Each separation 
interface consists of four dual-squib release-nut mechanisms 
that provide the structural load path across the four interface 
hardpoints and four caged stoke spring assemblies that provide 
the separation force. 



JET PROPULSION LABORATORY: 
GUIDANCE AND CONTROL DIVISION 

J13 Mariner Mars 1971: Guidance and Control 
[September-October 1970] 

Jet Propulsion Laboratory: Guidance and Control Division 

Fliglit Projects, Space Programs Summary 37-66, Vol. I, 
pp. 4-8, November 30, 1970 

Calibration of the reference and telemetry /monitor potentiome- 
ters that was performed on the scan electronics proof test model 
is described in this article. The calibration procedure was 
developed for use on the Mariner Mars 1971 Project. The refer- 
ence potentiometers store the scan platform reference angles in 
such a way that each stored angle is proportional to the voltage 
on the reference potentiometer wiper. The telemetry /monitor 
potentiometer is mechanically coupled to the reference potenti- 
ometer and is used to monitor the position of the reference 
potentiometer and, hence, the stored reference angle. The stored 
angle may be varied in increments by stepping the reference 
potentiometer shaft by a drive mechanism. Calibration was 



189 



achieved by recording the potentiometer wiper positions as 
functions of a number of position increments. 

An important activity in building an attitude-control gas system 
is the proper sizing of the gas nozzles to meet spacecraft control 
torque requirements. A nozzle-sizing computer analysis program 
and a thrust measurement stand are utihzed. With two exceptions 
that necessitated additional test work, the procedure is similar 
to that developed for the Mariner Mars 1969 Project. The two 
exceptions, the test program, and the resulting conclusions are 
discussed. 

J 14 Viking, Orbiter System: Guidance and Control 

[September-October 1970] 

Jet Propulsion Laboratory: Guidance and Control Division 

Fiight Projects, Space Programs Summary 37-66, Vol. !, 
pp. 47-51, November 30, 1970 

During the orbit of Mars by the Viking orbiter system, the Sun 
will periodically be occulted. The design of the circuit for auto- 
matic sensing of occultation and the associated logic is presented 
in this article. 

An articulation control subsystem has been proposed for the 
Viking spacecraft. Similar subsystems whose prime function is 
the articulation of bodies on spacecraft would be combined into 
a single subsystem. This article describes the design of a stepper 
motor control system that offers an excellent opportunity for a 
substantial hardware savings by multiplexing or time-sharing 
a major portion of the circuitry among the various functions 
in the subsystems. This is possible without any degradation in 
accuracy or performance. The only difference between the two 
designs being evaluated is the error-correction technique. One 
employs an error-actuated constant-rate mechanization, while the 
other corrects continuously, using a rate proportional to the error 
amplitude. A description of the systems functional elements 
and the results of an error analysis are included. 



JET PROPULSION LABORATORY: 
MARINER MARS 1971 PROJECT 

J15 Mariner Mars 1971: Project Description 

[September-October 1970] 

Jet Propulsion Laboratory: Mariner Mars 1971 Project 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 1-2, November 30, 1970 



190 



The primary objective of the Mariner Mars 1971 Project is to 
place two spacecraft in orbit around Mars that will be used 
to perform scientific experiments directed toward achieving a 
better understanding of the physical characteristics of that 
planet. Principal among these experiments are measurements of 
atmospheric and surface parameters at various times and loca- 
tions to determine the dynamic characteristics of the planet. 
An engineering objective is to demonstrate the ability of the 
spacecraft to perform orbital operations in an adaptive mode 
wherein information from one orbital pass is used to develop the 
operations plan for subsequent orbital passes. Specific mission 
objectives, the spacecraft, its scientific experiments, and manage- 
ment and support responsibilities for the project are briefly 
described. 



JET PROPULSION LABORATORY: 

MARINER VENUS-MERCURY 1973 PROJECT 

J16 Manner Venus-Mercury 1973: Project Description 
[September-October 1970] 

Jet Propulsion Laboratory: /War/ner Venus-iVIercury 1973 Project 

Ffight Projects, Space Programs Summary 37-66, Vol. 1, 
p. 31, November 30, 1970 

The primary objective of the Mariner Venus-Mercury 1973 
Project is to launch one spacecraft in October 1973 to obtain 
environmental and atmospheric data for the planet Venus in 
February 1974 and to conduct exploratory investigations of the 
planet Mercury's environment, atmosphere, surface, and body 
characteristics some 7 wk later, with first priority assigned to the 
Mercury investigations. The secondary objectives are to perform 
interplanetary experiments enroute to Mercury and to obtain 
experience with the gravity-assist mission mode. The spacecraft, 
its scientific experiments, and preliminary project planning are 
described. 



JET PROPULSION LABORATORY: 
PROPULSION DIVISION 

J17 Mariner Mars 1971: Propulsion [September-October 1970] 

Jet Propulsion Laboratory: Propulsion Division 

Flight Projects, Space Programs Summary 37-66, Vol. 1, 
pp. 12-21, November 30, 1970 

The Mariner Mars 1971 spacecraft incorporates an on-board 
modularized propulsion subsystem to furnish impulse to the 



191 



spacecraft for trans-Mars trajectory correction, orbit insertion, 
and orbit trims. The propulsion subsystem operates on the 
liquid propellants nitrogen tetroxide and monomethylhydrazine. 
The effects of propellant saturation with gaseous nitrogen on the 
hydrauhc resistance are discussed. 

Standard laminate Teflon bladder bags employed as liquid- 
propellant expulsion devices have failed due to the formation 
of tears and cracks near an aluminum seal ring that forms the 
mouth of the bag. These failures occurred during flight- 
acceptance tests in which various solvents were used as referee 
fuels. From a consideration of the conditions imposed on the 
bags during the tests, it was recognized that the neck regions 
of the bags are biaxially stressed while, at the same time, being 
bathed by the test solvent. This article presents the results of 
a study on the efi:ects of solvents on the biaxial properties 
of standard laminate materials. Also included are test results 
obtained on a new candidate material designated codispersion 
laminate, as well as the results of a study on the effects of 
solvents on the Teflon components used in the construction of the 
laminate materials. 



JET PROPULSION LABORATORY: 
SPACE SCIENCES DIVISION 

J 18 Mariner Venus-Mercury 1973: Space Sciences 

[September-October 1970] 

Jet Propulsion Laboratory: Space Sciences Division 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 32-37, November 30, 1970 

The objectives of the Mariner Venus-Mercury 1973 imaging 
experiment are to: (1) map and identify the major physiographic 
province of Mercury on the basis of topographic forms and 
optical properties of surface materials; (2) determine the simi- 
larities and differences between the major surface features of 
Mercury and those on the earth, the moon, and Mars, with 
special emphasis on the recognition of endogenic structures; 
(3) determine the distribution of surface features with reference 
to the dynamic axes of Mercury and investigate the boundaries 
with surrounding terrain; and (4) establish correlations with 
earth-based observations. For the planet Venus, close-up photog- 
raphy will produce additional spectral, radio emission, and radio 
occultation observations. This article discusses the scientific infor- 
mation about the planets that will be obtained with the experi- 
ment, the interplanetary measurements that will be performed. 



192 



the in-flight cahbration and test observations, and the preliminary 
mission sequence. A description of the television subsystem is 
included. 



JET PROPULSION LABORATORY: 
TELECOMMUNICATIONS DIVISION 

J 19 Mariner Venus-Mercury 1973: Telecommunications 
[September-October 1970] 

Jet Propulsion Laboratory: Telecommunications Division 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 37-41, November 30, 1970 

It is planned that the Mariner Venus-Mercury 1973, as well as 
the Mariner Mars 1971 and Viking, spacecraft communications 
systems will use science data words whose lengths are different 
from the 6-bit block-coded words that will be transmitted over the 
spacecraft-to-earth communications links and received with 
the multi-mission telemetry system of the Deep Space Network. 
In the analysis presented in this article, science words of length 
M bits are assumed to be serially time-multiplexed onto the 6-bit 
words. These 6-bit words are mapped onto (32,6) biorthogonal 
coded words and transmitted from the spacecraft to earth. The 
6-bit coded words are received and block decoded, and then 
the science words are decommutated from the received serial 
bit stream. The analysis shows the error rate for the data words 
of various word lengths when the error rate for 6-bit coded 
words is known. 



J20 Viking: Telecommunications [September-October 1970] 

Jet Propulsion Laboratory: Telecommunications Division 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 43^7, November 30, 1970 

The Viking relay link will operate at various times during the 
mission to provide the capability for lander-to-orbiter (uplink) 
and orbiter-to-lander (downlink) communications via a UHF 
channel. The uplink will be supported by a telemetry transmitter 
in the lander and a telemetry receiver/detector in the orbiter. 
The downlink will be supported by an amplitude-modulated 
transmitter in the orbiter and a receiver/tone detector in the 
lander. Previous flight projects have not used relay links, and 
the design of this link represents a first effort in many areas. 



193 



Accordingly, little experience is available on which to base pre- 
dictions of performance. To ensure integrity of design and to 
evaluate link parameters, a simulation program was undertaken 
to duplicate link signals at various mission phases and to measure 
actual equipment responses. The background, objectives, and 
test configuration for this simulation program are described in 
this article. 



JET PROPULSION LABORATORY: 

VIKING PROJECT 

J21 Viking: Project Description and Status 

[September-October 1970] 

Jet Propulsion Laboratory: Viking Project 

Flight Projects, Space Programs Summary 37-66, Vol. I, 
pp. 42^3, November 30, 1970 

The primary objective of the Viking Project is to significantly 
advance current knowledge of the planet Mars by direct meas- 
urements in the atmosphere and on the surface and by observa- 
tions of the planet during approach and from orbit. Particular 
emphasis will be placed on obtaining information concerning 
biological, chemical, and environmental factors relevant to the 
existence of life on the planet at this time or some time in 
the past or the potential for the development of life in the 
future. Two spacecraft, each consisting of an orbiter system and 
a lander system, are planned for launch during the 1975 oppor- 
tunity. The orbiter system is being developed by JPL; Langley 
Research Center is responsible for the lander system, being 
developed under contract by the Martin-Marietta Corporation. 
Langley Research Center also has overall management responsi- 
bility for the project. The specific objectives for the orbiter 
system and the lander system are described. Status information 
includes reviews, breadboard testing, and engineering model 
design. 



JU¥INALL, G. L 

J22 Studies of the Reaction Geometry of the 
Alkaline Silver Electrode 

G. L. Juvinall 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 82-84, 
October 31, 1970 



194 



The results of studies of the phenomena occurring at the surface 
of the alkahne silver electrode during electrochemical oxidation 
are reported. The scanning electron microscope was used for 
observing the reaction sites. The rmique capabilities of this in- 
strument permit definite conclusions to be drawn concerning the 
nature of the reactions taking place on the electrode surface. 
Photographs with magnification in the range of 10,000 to 13,000 
are included. 



KALFAYAN, S. H. 

KOI Evaluation of Spacecraft Magnetic Recording Tapes 
and Magnetic Heads [August-September 1970] 

S. H. Kalfayan, R. H. Silver, and J. K. Hoffman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Hi, pp. 158-171, 
October 31, 1970 

Monel-metal-bracketed magnetic heads were compared to brass - 
bracketed heads in their behavior toward 3M 20250 magnetic 
recording tape. The two kinds of heads showed about the same 
degree of frictional resistance and stickiness, under various en- 
vironmental conditions, to new, outgassed, and "vacoted" 3M 
20250 tape specimens. 



K02 Evaluation of Recording Tape and Heads for 

Spacecraft Magnetic Tape Recorder Applications 
[October-November 1970] 

J. K. Hoffman, S. H. Kalfayan, and R. H, Silver 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, p. 160, 
December 31, 1970 

For abstract, see Hoffman, J. K. 



K03 Evaluation of Magnetic Recording Tapes: A Method for the 
Quantitative Determination of Stick-Slip 

R. H. Silver, S. H. Kalfayan, and J. K. Hoffman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 198-200, 
December 31, 1970 

For abstract, see Silver, R. H. 



195 



KATOW, M. S. 

K04 DSN Progress Report for November-December 1970: Antenna 
Structures: Evaluation of Reflector Surface Distortions 

M. S. Katow 

Technical Report 32-1526, Vol. i, pp. 76-80, 
February 15, 1971 

The reflector surface distortions of the 210-ft-diam antenna, as 
evaluated by the linearized formulation of the rms paraboloid best- 
fitting computer program, has provided suiEcient significant digits 
in its answers for meaningful results. This article presents a clearer 
documentation as well as the error bounds of the formulation. 
Since basically the solution is a non-linear problem, improved 
formulation would be desirable. However, the program should 
be useful for evaluating larger than 210-ft-diam antennas with 
about the same degree of distortion. 



KELLER, 0. F. 

K05 Materia! Compatibility [August-September 1970] 

0. F. Keller and L. R. loth 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 180-181, 
October 31, 1970 

A material compatibility program is in progress to evaluate the 
effects of long-term storage of earth-storable propellants with 
selected materials of construction for spacecraft propulsion sys- 
tems. All aspects of the total system are considered and include 
propellant, material, test fixture, test container, instrumentation, 
test environment, and facility. The present status of specimen/ 
capsule testing at the Edwards Test Station is reported. Fuel 
specimen/capsules, imder test at 110°F, are described and pre- 
liminary resxdts of post-test evaluations are discussed. 



KINNEY, I. P. 

K06 A System of Computer Programs for interactive 

Trajectory Design 

T. P. Kinney 

Supporting Researcli and Advanced Development, 
Space Programs Summary 37-65, Vol. Mi, pp. 12-15, 
October 31, 1970 



196 



Mission trajectory design lias been accomplished at JPL with the 
aid of various computer programs that are run sequentially. The 
procedure is vulnerable to delays caused by normal processing of 
the individual computer runs. The Flight Path Design (system 
of) Program(s), FPDP, allows the analyst to perform a major 
portion of necessary design work from a remote computer termi- 
nal. Intermediate graphical output is displayed on a cathode-ray 
tube. The analyst interacts with FPDP, modifying parameters 
and cueing programs, thus obtaining in a single computer run 
results which previously required several passes. Significant de- 
creases in both man and machine time can be achieved. 



KNOELL, A. C. 

K07 Basic Concepts in Composite Beam Testing 

J. V. Mullin (General Electric Company) and A. C. Kneel! 
Mater. Res. Stan., Vol. 10, No. 12, pp. 16-33, December 1970 
For abstract, see Mullin, J. V. 

KOCH, R. E. 

K08 The Manner VI and VII Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 

KOLBLY, R. B. 

K09 Switched-Carrier Experiments 

R. B. Kolbly 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 84-88, November 30, 1970 

This article describes experiments to investigate the feasibility 
of time sharing a klystron amplifier between two uplink channels 
in order to simultaneously track two spacecraft. Two frequency 
experiments are described. 



197 



KROLL, G. 

KIO DSS 61/63 Facility l\/l(Kiifications and Construction 

R. Casperson, G. Kroll, and L. Kushner 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 154-158, November 30, 1970 

For abstract, see Casperson, R. 



KUIPER, G. P. 

Kl 1 Surveyor Final Report— Lunar Theory and Processes: 

Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gault (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 
H. Masursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 

K12 Surveyor Final Report— Lunar Theory and Processes: 

Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 
of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 
R. A. Phinney (Princeton University), and 

E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

For abstract, see Gault, D. E. 



KURIGER, W. L 

K13 A Proposed Laser Obstacle Detection Sensor for a Mars Rover 

W. L. Kuriger (University of Oklahoma) 

Supporting Research and Advanced Developnnent, 
Space Programs Summary 37-66, Vol. Ill, pp. 80-89, 

December 31, 1970 

A mechanization is proposed for a laser obstacle detector that 
has characteristics appropriate for a Mars rover. This application 
will require the utmost possible in simplicity, small size, and 



198 



minimum power needs. A pulsed gallium-arsenide laser is 
suggested, scanned in a vertical plane, together with an ava- 
lanche photodiode detector for ranging between 5 and 30 m. 
A discussion of a simple signal-processing technique is included, 
and the expected signal-to-noise ratio is calculated. 



KUSHNER, L H. 

K14 DSS 61/63 Facility IViodifications and Construction 

R. Casperson, G. Kroll, and L. Kushner 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 154-158, November 30, 1970 

For abstract, see Casperson, R. 

K15 85-ft-diam Antenna Tracking Station Power Plant 
Reconfiguration 

L. H. Kushner 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. 11, pp. 159-160, November 30, 1970 

The existing power plants of the seven Deep Space Instrumenta- 
tion Facility 85-ft tracking stations are planned for reconfigura- 
tion. This article summarizes the reconfiguration plans, which 
include modification/rearrangement of existing power plant 
equipment and installation of new equipment. The final con- 
figuration is directed toward a standardization of power gener- 
ating units consisting of one size diesel engine (Caterpillar D-398) 
driving 350- and 50-kW generators. This standardization provides 
for required operational power growth of stations with minimum 
number of different size/ratings of engine-generator units. 



LACY, G. H. 

LOl Soil Microbial and Ecological Investigations in 
the Antarctic Interior 

R. E. Cameron, R. B. Hanson, G. H. Lacy, and F. A. Morelli 

Antarc. J. U.S., Vol. V, No. 4, pp. 87-88, July-August 1970 

For abstract, see Cameron, R. E. 

L02 Microbiological Analyses of Snow and Air From 
the Antarctic Interior 

G. H. Lacy, R. E. Cameron, R. B. Hanson, and F. A. Morelli 



199 



Antarc. J. U.S., Vol. V, No. 4, pp. 88-89, July-August 1970 

Snow and air were collected by aseptic techniques and examined 
for the presence of microorganisms at the Beardmore camp (ap- 
proximately 84° IT'S, 162°22'E; 2100-m elevation) on the Walcott 
Neve, Queen Alexandra Range, during the austral summer 1969- 
1970. The results of the analyses performed are briefly discussed 
in this article. 



LAESER, R. P. 

LOS DSN Progress Report for November-December 1970: 
Mariner Mars 1971 Mission Support 

R. P. Laeser 

Technical Report 32-1526, Vol. I, pp. 4-6, February 15, 1971 

The Deep Space Network (DSN) support plans for the Mariner 
Mars 1971 mission have been modified by a move of the analog 
playback function from the Space Flight Operations Facility 
media conversion center to the Deep Space Instrumentation 
Facility Compatibility Test Area and by the DSN assumption 
of the responsibility for sequence of event generation computer 
software. Both of these new plans are discussed. 



LA FRIEDA, J. 

L04 Space Station Unified Communication: Optimum Performance 
of Two-Channel High-Rate Interplex Systems 

J. La Frieda 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 31-36, 
October 31, 1970 

The optimum data efficiency and bit-error performance of two- 
channel digital coherent systems are determined, where the data 
signals phase-modulate an RF carrier with biphase-modulated 
sine-wave subcarriers. Two types of phase modulation are con- 
sidered: linear binary phase-shift keying (BFSK) and interplex 
BPSK. It is shown that interplex BPSK outperforms linear BPSK 
and that the improvement in performance increases as the ratio 
of channel data rates (power) approaches unity. The sine-wave 
subcarriers considered are necessary in the Manned Space Sta- 
tion, where the data rates are so high that square-wave sub- 
carriers can not be considered. 



200 



LAN DEL, R. F. 

LOS On the Presence of Crystallinity in Hydrogenated 
Polybutadienes 

J. Moacanin, A. Eisenberg (McGill University, Canada), 
E. F. Cuddihy, D. D. Lawson, B. G. Moser (i\floser Dental 
iVlanufacturing Company), and R. F. Landel 

Technical Report 32-1512 (Reprinted from J. Appl. Polym. Sci., 
Vol. 14, No. 9, pp. 2416-2420, September 1970) 

For abstract, see Moacanin, J. 



LAUE, E. 

LOS Multichannel Radiometer Narrow-Band Solar Spectra! 
Irradiance at 75 km 

E. Laue 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 158-162, 
October 31, 1970 

Spectral filter radiometric measurements of the solar irradiance 
obtained during an X-15 flight approximately 80 km above the 
earth's surface are compared with four normalized solar spectral 
curves. A solar spectral irradiance curve is developed using por- 
tions of those curves whose integrated pass-band values most 
nearly approach the X-15 measurements. 



LAWSON, D. D. 

L07 On the Presence of Crystallinity in Hydrogenated 
Polybutadienes 

J. Moacanin, A. Eisenberg (McGill University, Canada), 
E. F. Cuddihy, D. D. Lawson, B. G. Moser (Moser Dental 
Manufacturing Company), and R. F. Landel 

Technical Report 32-1512 (Reprinted from J. Appf. Polym. Sci. 
Vol. 14, No. 9, pp. 2416-2420, September 1970) 

For abstract, see Moacanin, J. 



LAYLAND, J. W. 

LOS An Optimum Squaring Loop Prefilter 

J.W. Layland 

201 



IEEE Trans. Commun. Techno!., Vol. COM-IS, No. 5, 
pp. 695-697, October 1970 

Squaring loops are often discussed as a means of establishing a 
coherent carrier reference for bi-phase PSK (phase-shift-keyed) 
modulation. The optimal presquaring filter is derived under the 
assumptions that the modulating spectrum is narrow with respect 
to the carrier frequency and that the phase-locked loop band- 
width is much narrower than the modulating spectrum. 



LEAHEY, C. F. 

L09 DSN Progress Report for November-December 1970: Mark IIIA 
Simulation Center EMR 6050-Univac 1108 Computer Interface 

C. F. Leahey 

Technical Report 32-1526, Vol. I, pp. 88-92, 

February 15, 1971 

The Mark IIIA simulation center is capable of simultaneously 
simulating two spacecraft and three deep space stations using 
the Univac 1108 and EMR 6050 computers. The EMR 6050 
and the Univac 1108 were interfaced using Bell System 303C 
modems and a JPL-designed interface adapter. The design of the 
interface was constrained by two factors: (1) the final location of 
the Univac 1108 was undetermined at the time of finalization 
of the interface assembly design, and (2) the EMR 6050 and the 
Univac 1108 have different word lengths. The hardware and 
software approaches used to satisfactorily mate the two com- 
puters are explained. 



LEAVITT, R. K. 

LIO DSN Progress Report for November-December 1970: 
Refractivity Influence on DSS Doppler Data 

F. B. Winn and R. K. Leavitt 

Technical Report 32-1526, Vol. I, pp. 31^1, 
February 15, 1971 

For abstract, see Winn, F. B. 



LEONARD, W. D. 

LI 1 Thermoelectric Generator Performance Correlation 
W. D. Leonard (Resalab, Inc.) 

202 



Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 89-95, 
October 31, 1970 

The experimental test results of a thermoelectric generator were 
compared to the analytically predicted performance. The gen- 
erator under consideration was a thermoelectric generator de- 
signed and built by RCA and referred to as the RCA reference 
design converter. The method used to calculate the performance 
of the generator is detailed to illustrate the flexibility of a com- 
puter code to predict the performance of a variety of thermo- 
electric generator designs. Included in the analysis is the method 
used to account for extraneous resistance and shunt heat losses. 

LEVY, G. S. 

L12 The Quasi-Stationary Coronal Magnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

C. T. Stelzried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison, (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), and 
J. M. Wilcox (University of California, Berkeley) 

Sol. Phys., Vol. 14, No. 2, pp. 440-^56, October 1970 

For abstract, see Stelzried, C. T. 

LEVY, R. 

LIB DSN Progress Report for November-December 1970: Antenna 
Rigging Angle Optimization Within Structural Member Size 
Design Optimization 

R. Levy 

Technical Report 32-1526, Vol. I, pp. 81-87, 
February 15, 1971 

It is shown in this article that the horizon rms deviation of the 
antenna from the best-fitting paraboloid is a representative 
measure of the cosine-weighted average rms for the complete 
elevation attitude range. Therefore, the horizon rms can be used 
as a substitute merit function in a structural redesign program 
that generates improved member size distributions to reduce 
the weighted-average rms. VaHdity of the substitution follows 
because: (1) the optimal rigging angle is a slowly changing func- 
tion of changes in member size distributions; (2) the weighted 
average rms is not sensitive to small rigging angle changes; (3) at 
rigging angles near the optimal, ranking according to the mini- 
mum horizon rms is equivalent to ranking according to the 



203 



minimum cosine-weighted average for alternative designs with 
different member size distributions. 



LEWIS, J. C. 

L14 Crack Propagation Threshold for Isopropanol and 
Ti-5AI-4V Titanium Alloy 

J. C. Lewis 

Supporting Research arid Advanced Development, 
Space Programs Summary 37-65, Voi. Ill, pp. 131-135, 
October 31, 1970 

Stress corrosion crack propagation data for isopropanol and 
Ti-6A1-4V titanium alloy are reported. The fracture mechanics 
approach was used to determine the stress intensity at which 
crack growth began in isopropanol at 7(>-80°F and 300 ±20 psig 
for 96 h. A threshold of approximately 38 ksi-in.'''" was observed 
for isopropanol as compared to approximately 40 ksi-in.*'° for in- 
hibited nitrogen tetroxide on the same material under the same 
conditions. 



LEWIS, R. A. 

L15 A Computerized Landmark Navigator: Development 

and Test Plan 

R. A. Lewis 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 1-2, 
October 31, 1970 

A computer program that determines the position and heading 
of a roving vehicle on the lunar surface has been developed. The 
assumptions, hardware, and inputs required by the algorithm are 
minimal in the sense that the requirements of the program are 
met by the general lunar terrain and baseline roving vehicle. This 
article describes the algorithm, the use of the computer program, 
and a planned series of tests to evaluate the capabilities of the 
program. 

L16 Roving Vehicle Navigation Subsystem Feasibility Study: 
Inertia! and Gyrocompass/Odometer Navigators 

R. A. Lewis 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 105-107, 
October 31, 1970 



204 



A roving vehicle motion control computer simulation has been 
applied to determine the feasibility of two automated roving ve- 
hicle navigation subsystems. An inertial navigator using a triad 
of mutually orthogonal accelerometers mounted on a platform 
stabilized by three single-degree-of -freedom gyros was simulated 
and the configuration was found to be infeasible when the char- 
acteristics of state-of-the-art hardware were assumed. A naviga- 
tion configuration using gyrocompass and odometer was found to 
be feasible under the assumptions of the study. 



LI, S. P. 

L17 A Survey of Hardening Techniques for a Complementary- 
Symmetry MOSFET Memory 

S. P. Li 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 152-155, 
October 31, 1970 

Current techniques in hardening metal-oxide semiconductor de- 
vices against radiation damage are surveyed and reported, with 
the possibility of a complementary-symmetry metal-oxide semi- 
conductor field-efiFect transistor (MOSFET) memory on long mis- 
sions considered. The silicon oxynitride film, in place of silicon 
dioxide in the regular MOSFET, appears most promising. Suffi- 
ciently hard laboratory samples are already available, while large 
scale integration techniques are yet to be developed. 

L18 Jupiter's Electron Dose Calculations on IVIetai Oxide 
Semiconductor Structures 

S. P. Li and J. B. Barengoltz 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 166-170, 
December 31, 1970 

Estimates of the effects on metal oxide semiconductor devices 
onboard an outer-planet spacecraft due to the trapped electrons 
at Jupiter have been made. The system was modeled by an 
aluminum-silicon sandwich, lying behind a magnesium shield. 
The aluminum layer was taken to be 6000 angstrom, the silicon 
layer 2000 angstrom, and the magnesium shield between 50 
and 500 mils thick. The ionization dose absorbed by the silicon 
due to a suitable spectral model of Jovian electrons was calcu- 
lated, including bremsstrahlung. Results of the calculations show 
an expected dose due to electrons of 2 X 10^ rad, to which the 
bremsstrahlung contribution was less than 3%. 



205 



LIKINS, P. V^. 

L19 Finite Element Modeling for Appendage Interaction With 

Spacecraft Control 

P. W. Likins (University of California, Los Angeles) and 

E. L. Marsh 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. IN, pp. 100-105, 
December 31, 1970 

A hybrid coordinate formulation has been previously developed 
and applied to the analysis of the effect of flexible appendages 
on spacecraft flight control systems. This article presents a syn- 
opsis of an improved flexible appendage model which utilizes 
finite element analysis. This model has been incorporated into 
the hybrid coordinate formulation. The finite element analysis 
provides for more accurate prediction of spacecraft flight control 
performance. 



LINDSEY, W. C. 

L20 The Effect of Loop Stress on the Performance of 
Phase-Coherent Communication Systems 

W. C. Lindsay (University of Southern California) and 
M. K. Simon 

IEEE Trans. Commun. Techno/., Vol. COM-18, No. 5, 
pp. 559-588, October 1970 

In phase-coherent communication systems which use phase- 
locked loops to provide synchronization of the data detector, 
the communications engineer is frequently faced with the prob- 
lem of determining the effects of noisy timing upon detection 
efficiency. This paper is concerned with determining these effects 
when second-order phase-locked loops, operating in the presence 
of frequency detuning, are used as a means of providing phase 
synchronization. The results are also apphcable to the problem 
of establishing noisy reference losses in a broad class of coherent 
pulse-code-modulated telemetry systems (e.g., pulse-code- 
modulated/phase-shift-keyed/phase-modulated). Also presented 
are results which can be used to determine steady-state statistical 
dynamics of second-order loops. 



LIVANOS, A. C. R. 

L21 Diffraction of a High-Order Gaussian Beam by an Aperture 

A. C. R. Livanos 



206 



Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 181-186, 
December 31, 1970 

In this article the diffraction of a high-order gaussian beam by 
an aperture is examined. The beam considered corresponds to the 
transfer electromagnetic mode of a laser, which, after leaving 
the resonator, is focused by a lens and then diffracted by an 
aperture located at the focal point. The intensity distribution 
of the diffracted beam is calculated using Huygen's principle, 
and employing approximations that are weaker than those of 
Fresnel and Fraunhofer. 



LUCAS, J. W. 

L22 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffa, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffe, L. D. 

L23 Revised Lunar Surface Thermal Characteristics Obtained 
From the Surveyor V Spacecraft 

L. D. Stimpson and J. W. Lucas 

J. Spacecraft Rockets, Vol. 7, No. 11, pp. 1317-1322, 
November 1970 

For abstract, see Stimpson, L. D. 



LUNDY, C. C. 

L24 Thrust Collar Survey (DSS 14) 

C. C. Lundy 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 77-80, November 30, 1970 



207 



In the 210-ft-diameter antennas, radial loads of a few hundred 
tons exist between the rotating alidade and the fixed thrust 
collar. The thrust collar resists these loads and also defines the 
axis of rotation in azimuth. This article describes the installation 
of 24 monuments in the radial bearing thrust collar at DSS 14 
(Mars Deep Space Station). The monuments form a net of sur- 
veyed points from which the circularity of the radial bearing 
runner can be measured. 



LUTWACK, R. 

L25 Permeability of Membranes 

R. Lutwack 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. HI, p. 81, 
October 31, 1970 

The diffusive transport of K% H2O, and Zn species has been 
measured for a system containing the SWRI-GX separator ma- 
terial and concentrated KOH solutions. The value of the mass 
transfer coefficient for Zn makes untenable the assumption that 
only the Zn(OH) =species is present in the KOH solutions. 



LYON, R, B. 

L25 Improved RF Calibration Techniques: A Study of the RF 
Properties of the 210-ft-diam Antenna Mesh Material 

T. Y. Otoshi and R. B. Lyon 

The Deep Space Network, Space Programs Summary 37-66, 
VoL II, pp. 52-57, November 30, 1970 

For abstract, see Otoshi, T. Y. 



L27 Improved RF Calibration Techniques: PDS Cone 
Waveguide/Polarimeter Calibrations 

P. D. Batelaan, B. Seidel, and R. B. Lyon 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 61-63, November 30, 1970 

For abstract, see Batelaan, P. D. 



208 



MacDORAN, P. F. 

MOl DSN Progress Report for November-December 1970: Probing 
the Solar Plasma With Mariner Radio Metric Data, 
Preliminary Results 

P. F. MacDoran, P. S. Callahan, and A. I. Zygielbaum 

Technical Report 32-1526, Vol. I, pp. 14-21, February 15, 1971 

A radio technique exploiting the opposite changes of group and 
phase velocity in a dynamic plasma was used to probe the solar 
corona during the superior conjunctions of the Mariner VI and 
VII spacecraft. From an analysis of range and doppler radio 
metric data generated by the Deep Space Network (DSN) in 
tracking the spacecraft, it was possible to establish a correspon- 
dence between plasma fluctuations in the radio raypath and 
McMath sunspot regions on the solar surface. Estimates of 3000 
electrons/cm^ and scale sizes of 6 X 10* and 2 X 10" km were 
made for plasma clouds transisting the radio path when tracking 
within a few degrees of the sun. 



MacGLASHAN, W. F. 

M02 Component Storage With Propellants 

W. F. MacGlashan and L. R. Toth 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. ill, p. 179, 
October 31, 1970 

Fill valves and service connections were tested for 3 mo with 
pressurized (400 psig) OF2 and BaHg at — 230°F. A separate 
environmental testing chamber was used for each of the two 
propellants. Each chamber contained an aluminum, stainless 
steel, and titanium fill valve and two service connections. Post- 
test evaluations for internal leakage are being performed and the 
work wUl be concluded with a metallurgical analysis of all 
components. 



MACK, L M. 

MOB Response of Supersonic Laminar Boundary Layer to a 
Moving External Pressure Field 

L. M. Mack 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 13-16, 
December 31, 1970 



209 



The response of a laminar boundary layer to the external pressure 
field created by a wavy wall moving supersonically with respect 
to the free stream is computed numerically using modifications 
of the inviscid and viscous computer programs originally devel- 
oped for linear stability theory. Specific results are given at a 
free-stream Mach number of 4.5 for an insulated-wall boundary 
layer. It is found that an effective amplification occurs at low 
Reynolds number which increases the peak mass-flow fluctua- 
tion in the boundary layer by 10-20 times over the free-stream 
value of the external pressure field. The Reynolds number at 
which this amplification ceases increases with decreasing fre- 
quency and is well within the laminar instability region for a 
wide range of frequencies. 



MARKO, W. J. 

M04 Near-Field Supersonic Boom Pressure Tests in 
the JPL 20-in. Supersonic Wind Tunnel 

W. J. Marko 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 156-157, 
October 31, 1970 

Near-field supersonic boom pressure measurements have been 
recorded for ten combinations of two wing and five nose config- 
urations in the JPL 20-in. supersonic wind tunnel at Mach num- 
bers of 1.68 and 2.7. Data demonstrating the effects of lift and 
configuration changes on the near-field overpressure were ob- 
tained. 



MARSH, E. L. 

M05 The Attitude Control of a Flexible Solar Electric Spacecraft 

E. L. Marsh 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 92-99, 
December 31, 1970 

The problem of the attitude control of a solar electric spacecraft 
is studied. A linear analysis of the system of differential 
equations of attitude motion was performed. Root locus and 
eigenvalue procedures were utilized for determining stable 
configurations. Parametric studies, where the varying parameters 
were the gains of the sensor units associated with the control 
system, were made. 



210 



M06 Finite Element Modeling for Appendage Interaction With 
Spacecraft Control 

P. W. Likins (University of California, Los Angeles) 
and E. L. Marsh 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 100-105, 
December 31, 1970 

For abstract, see Likins, P. W. 



MARTIN, K. E. 

M07 Radiation Effects on Electronic Parts; Literature Search and 
Data Evaluation 

K. E. Martin 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 145-147, 
December 31, 1970 

A survey has been made of the radiation effects literature perti- 
nent to the influence of low-level steady-state neutron, gamma, 
and proton environments on electronic components. The accumu- 
lated data are reviewed and an analysis is made of the radiation 
effects on electronic components estimated to comprise a deep 
space mission spacecraft exposed to planetary radiation belts 
and to on-board radioisotope thermoelectric generator environ- 
ments. Emphasis was placed on permanent parameter degrada- 
tion, temporary parameter drifts, parameter degradation factors, 
hardening techniques, and screening techniques. 



MASEK, T. D. 

M08 Thrust Subsystem Design for Nuclear Electric Spacecraft 

T. D. Masek 

Supporting Researcli and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 207-210, 
December 31, 1970 

A method for sizing a nuclear electric thrust subsystem is pre- 
sented. The results are applied to a 300-kW spacecraft design. 
The resulting thrust subsystem mass is estimated to be about 
970 kg. 



211 



MASURSKY, H. 

M09 Surveyor Final Report— Lunar Theory and Processes: 
Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gauit (Ames 
Researcii Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 
H. iViasursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 



McCLURE, J. P. 

MIO Ground Communications Facility Functional Design for 

1971-1972 

J. P. McClure 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 99-102, November 30, 1970 

The Ground Communications Facihty (GCF) consists of four 
systems: voice, high-speed data, teletype, and wideband data. 
These systems are undergoing evolutionary change to accom- 
modate higher data rates and increased volumes of traffic for 
future space missions. This article discusses the general design 
of the GCF for the 1971-1972 era. The Voice System is changing 
only in regard to total number of circuits required. The High- 
Speed Data System is being upgraded to provide outbound, in 
addition to inbound transmission capability, data rate increase 
to 4800 bits/s, and increased block size from 600 to 1200 bits. 
The Teletype System remains essentially unchanged. The Wide- 
band System will provide 50-kbit/s data transmission capability. 



McCREA, F. E. 

Mil High-Power Feed Component Development 

F. E. McCrea, H. F. Reilly, Jr., and D. E. Neff 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 64-68, November 30, 1970 

Since the introduction of high-powered S-band transmitters 
(500 kW, CW) at the Venus (DSS 13) and Mars (DBS 14) Deep 
Space Stations, three feed systems, in various developmental 



212 



states, have been used. The components used in these systems 
are discussed, including rotary joints, waveguide transitions, 
quarter-wave plates, and an orthomode transducer. It is con- 
cluded that complex polarization diverse low-noise/high-power 
feeds are possible. 

Wil2 S-Band Polar Ultra Cone Improvement 

H. F. Reilly, Jr., and F. E. McCrea 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, p. 69, November 30, 1970 

For abstract, see Reilly, H. F., Jr. 



McELIECE, R. 

MIS Decoding and Synchronization Research: Euler Products, 
Cyclotomy, and Coding 

R. McEliece and H. Rumsey, Jr. 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 22-27, 
October 31, 1970 

A theorem of Davenport and Hasse is used to calculate the 
weight distributions of a large and important class of binary and 
nonbinary codes, the irreducible cyclic codes. A discussion on the 
cyclotomy of finite fields and some remarks about the recently 
investigated hyper -Kloosterman sums are included. 



MclNNIS.J. 

IVH4 High-Speed Data/Wide-Band Data Input/Output Assembly 

R. Wengert, L. DeGennaro, and J. Mclnnis 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 133-136, November 30, 1970 

For abstract, see Wengert, R. 

MENARD, W. A, 

M15 Shock-Tube Thermochemistry Tables for 
High-Temperature Gases: Nitrogen 

W. A. Menard and T. E. Norton 

Technical Report 32-1408, Vol. IV, December 1, 1970 



213 



Thermodynamic properties and species concentrations of equi- 
librium nitrogen are tabulated for moving, standing, and re- 
flected shock waves. Initial pressures range from 0.05 to 50.0 
torr, and temperatures from 2000 to over 75,000°K. 



MENICHELLI, V.J. 

M16 Terminated Capacitor Disciiarge Firing of 

Electroexplosive Devices 

L. A. Rosenthal (Rutgers University) and V. J. Menichelli 
Technical Report 32-1521, February 15, 1971 

For abstract, see Rosenthal, L. A. 

Ml/ Nondestructive Testing of 1-W, 1-A Electro-Explosive Devices 

[October-November 1970] 

V. J. Menichelli 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 175-178, 

December 31, 1970 

The results of dissecting a squib which gave abnormal responses 
to two nondestructive tests are presented. The heating curves 
indicated poor bridgewire welds and poor contact between 
bridgewires and explosive. The predictions were confirmed 
through the dissection. 



MILLER, C. G. 

M18 Holographic Study of Operating Compact-Arc Lamp 

C. G. Miller and 0. L. Youngberg 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 171-174, 
December 13, 1970 

Flash holograms have been made of a xenon compact-arc dis- 
charge while in operation. No evidence of gas density variation 
in the vicinity of the center core of the arc was found. With 
the anodes used, the holograms showed laminar flow at the inter- 
face of the arc stream-anode surface. Improvement in operation 
could be expected if turbulent flow could be induced. Electron 



214 



densities in the arc stream were shown to be too low to introduce 
significant refraction in looking through the arc. 



MILLER, L. F. 

MIS DSN Progress Report for November-December 1970: A 

Cursory Examination of the Sensitivity of tfie Tropospheric 
Range and Doppler Effects to the Shape of the 
Refractivity Profile 

L F. Miller, V. J. Ondrasik, and C. C. Chao 

Technical Report 32-1526, Vol. I, pp. 22-30, February 15, 1971 

The different shapes that refractivity profiles may assume during 
a year are grossly represented by 21 simple analytical expres- 
sions. As shown in this article, by comparing the results obtained 
by using ray tracing techniques on these various profiles, it is 
possible to obtain an approximate bound on the error induced by 
mapping a tropospheric zenith range effect down to lower eleva- 
tion angles with the wrong profile. For an elevation angle of 
10 deg, these approximate error bounds are 1.3 and 2.6% in the 
range and doppler effect, respectively. 



MILLER, L W. 

1VI20 DSN Status Code 

R. B. Rung and L W. Miller 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 141-143, November 30, 1970 

For abstract, see Rung, R. B. 

MITCHELL, R. T. 

M21 The Mariner VI and VU Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zieienback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 
For abstract, see Gordon, H. J. 



215 



MO, T. C. 

M22 Electromagnetic Wave Propagation in a Uniformly 
Accelerated Simple Medium 

T. C. Mo (California Institute of Teciinoiogy) 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 182-190, 
October 31, 1970 

Electromagnetic wave propagation in a uniformly accelerated 
simple medium is generalized to the case of arbitrary direction. 
The wave splits into two natural modes relative to the 
acceleration-propagation plane. The case of high frequency and 
weak acceleration is solved in detail, demonstrating an apparent 
gravity-dragging effect to medium comoving observers and an 
acceleration-dragging effect to inertial observers. A preferred 
asymptotic cone of propagation, with cone angle determined by 
the parameter {/xe — l)'''", where /x is the permeability and e is 
the dielectric constant of the medium, is found in the accelerated 
frame. Various dragging effects are physically interpreted. 



MOACANIN, J. 

M23 Superposition of Dynamic Mechanical Properties in the 
Glassy State 

E. F. Cuddiliy and J. Moacanin 

Technical Report 32-1509 (Reprinted from J. Polym. Sc/., 
Pt. A-2: Polym. Phys., Vol. 8, No. 9, pp. 1627-1634, 
September 1970) 

For abstract, see Cuddihy, E. F. 



M24 On the Presence of Crystallinity in Hydrogenated 

Polybutadienes 

J. Moacanin, A. Eisenberg (IVlcGili University, Canada), 
E. F. Cuddihy, D. D. Lawson, B. G. Moser (Moser Dental 
Manufacturing Company), and R. F. Lande! 

Technical Report 32-1512 (Reprinted from J. Appl. Polym. Sci., 
Vol. 14, No. 9, pp. 2416-2420, September 1970) 

A low level of crystallinity in hydrogenated hydroxy-terminated 
polybutadiene and in elastomers prepared from this prepolymer 
was surmised. However, no crystallinity could be detected by 
direct measurements such as X-rays or volume changes. This 



216 



article discusses recent results of optical and rheological meas- 
urements that provide evidence for the presence of very small 
crystallites. 

M25 Investigation of Sterilizable Battery Separators 
[August-September 1970] 

E. F. Cuddihy, D. E. Walmsley, J. Moacanin, and H. Y. Tom 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 171-176, 
October 31, 1970 

For abstract, see Cuddihy, E. F. 

M26 Viscoelastic Behavior of Elastomers Undergoing 
Crosslinking Reactions 

J. Moacanin and J. J. Aklonis (University of 
Southern California) 

Supporting Researcti and Advanced Deve/opment, 
Space Programs Summary 37-66, Vol. ill, pp. 187-189, 
December 31, 1970 

Previously a method was developed for predicting the visco- 
elastic response of elastomers undergoing scission reactions. 
These results are now extended to include crosslinking reactions. 
As for scission, at any given time, the character of the network 
chains is determined by the instantaneous crosslink density. For 
scission all chains were assumed to carry the same stress, whereas 
for crosslinking, stress is distributed between the "new" and "old" 
chains. Equations for calculating the relative stresses are derived. 



IVIOLINDER, J. I. 

M27 Space Station Unified Communication: Standard Run-Length 
Coding for Multi-Level Sources 

J. I. Molinder 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 39-40, 
October 31, 1970 

The optimum single-standard run lengths for a binary first-order 
Markov source are extended to multi-level first-order Markov 
sources. The optimal single-standard run length for each symbol 
is shown to satisfy an implicit equation of the same form as for 
the binary case. An expression for the resulting overall com- 



217 



pression ratio cannot be given in closed form, however. The 
optimum run lengths are determined by maximizing a quantity 
called the run-length compression ratio. This ratio is defined as 
the average compression ratio when runs of only one particular 
output symbol are considered. 



MORELLI, F. A. 

M28 Soil Microbial and Ecological Investigations in 

the Antarctic Interior 

R. E. Cameron, R. B. Hanson, G. H. Lacy, and F. A. Morelli 
Antarc. J. U.S., Vol. V, No. 4, pp. 88-89, July-August 1970 

For abstract, see Cameron, R. E. 

M29 Microbiological Analyses of Snow and Air From 

the Antarctic Interior 

G. H. Lacy, R. E. Cameron, R. B. Hanson, and F. A. Morelli 
Antarc. J. U.S., Vol. V, No. 4, pp. 88-89, July-August 1970 

For abstract, see Lacy, G. H. 

MORRIS, E. C. 

M30 Surveyor Final Report— Geology: Regional Setting 

E. C. Morris (U.S. Geological Survey) 

Icarus: /nf. J. So/. Sys., Vol. 12, No. 2, pp. 161-166, 
211-212, March 1970 

The landing sites for the five Surveyor spacecraft that success- 
fully soft-landed on the moon are as follows: 

Surveyor I. Flat surface inside a 100-km crater in Oceanus Pro- 
cellarum, 1 radius from the edge of a rimless 200-m crater. 

Surveyor III. Interior of a subdued 200-m crater, probably of 
impact origin, in Oceanus Procellarum. 

Surveyor V. Steep, inner slope of a 9- by 12-m crater, which 
may be a subsidence feature, in Mare TranquiUitatis. 

Surveyor VI. Flat surface near a mare ridge in Sinus Medii. 

Surveyor VII. Ejecta or flow blanket north of, and less than 1 
radius from, the rim of the crater Tycho in the highlands. 



218 



The general terrain in the area of these landing sites is described 
and illustrated in this article. 

MSI Surveyor Final Report— Geology: Craters 

E. C. Morris (U.S. Geological Survey) and 
E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 167-172, 
211-212, March 1970 

Small craters are the most abundant of the topographic features 
observed on the lunar surface and account for the irregularities 
of largest relief on the surface at the Surveyor landing sites in 
the maria. Several types of small craters can be recognized: (1) 
shallow, cup-shaped craters with subdued rims; (2) cup-shaped 
craters with sharp, raised rims; (3) rimless craters; and (4) irreg- 
ular or asymmetric craters. The characteristics of the craters at 
the Surveyor I, 111, V, VI, and VII landing sites are described 
in this article. 



M32 Surveyor Final Report— Geology: Fragmentaf Debris 

E. C. Morris (U.S. Geological Survey) and 
E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 173-187, 211-212, 
March 1970 

The surface on which the five successful Surveyor spacecraft 
landed consists of a fragmental debris layer, or regolith, com- 
posed of poorly sorted or well-graded fragments that range in 
size from large blocks to fine particles too small to be resolved 
by the Surveyor camera (<0.5 mm). The number of resolvable 
particles per unit area varies from site to site; 3 to 18% of the 
surface was found to be occupied by fragments larger than 1 mm. 
The fragmental debris at the Surveyor I, III, V, VI, and VII 
landing sites is described and illustrated in this article. 



IV133 Surveyor Final Report— Geology: Physics of Fragmental Debris 

E. M. Shoemaker (U.S. Geological Survey) and 
E. C. Morris (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 188-212, 
March 1970 

For abstract, see Shoemaker, E. M. 



219 



MOSER, B. G. 

M34 On the Presence of Crystallinity in Hydrogenated 

Polybutadienes 

J. Moacanin, A. Eisenberg (McGill University, Canada), 
E. F. Cuddihy, D. D. Lawson, B. G. iVioser (Moser Dental 
Manufacturing Company), and R. F. Landel 

Technical Report 32-1512 (Reprinted from J. Appl. Polym. Sci., 
Vol. 14, No. 9, pp. 2416-2420, September 1970) 

For abstract, see Moacanin, J. 



MOTTINGER, N. A. 

M35 Tracking System Analytic Calibration Activities for the 
Manner Mars 1969 Mission 

B. D. Muihall, C. C. Chao, N. A. Mottinger, P. M. Muller, 

V. J. Ondrasik, W. L. Sjogren, K. L. Thuleen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 

For abstract, see Muihall, B. D. 

M36 The Mariner VI and Vll Flight Paths and Their 

Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Muihall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinboid, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Bali, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 



MUDGWAY, D. J. 

M37 DSN Progress Report for November-December 1970: Viking 

Mission Support 

D.J. Mudgway 

Technical Report 32-1526, Vol. I, pp. 7-10, February 15, 1971 

The support provided to the Viking Project by the Tracking and 
Data System is discussed in the following areas: trajectory 
design factors, launch/arrival times, look angle between space- 
craft, communication range and signal level, solar conjunction, 
and near-earth phase trajectories. 



220 



MUHLEMAN, D. 0. 

iVI38 Surveyor Final Report— Principal Scientific Results 
From the Surveyor Program 

L. D. Jaffa, C. 0. Alley (University of Maryland), 
8. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-150, 
March 1970 

For abstract, see Jaffe, L. D. 



WtULHALL, B. D. 

WI39 Tracking System Analytic Calibration Activities for the 
Mariner Mars 1969 Mission 

B. D. Muihall, C. C. Chao, N. A. Mottinger, P. M. Muller, 
V. J. Ondrasik, W. L. Sjogren, K. L. Thuleen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 

This report describes the tracking system analytic calibration 
activities of the Deep Space Network in support of an entire 
mission, in particular, the Mars encounter phase of the Mariner 
Mars 1969 mission. The support functions encompass calibration 
of tracking data by estimating physical parameters whose uncer- 
tainties represent limitations to navigational accuracy; validation 
of the calibration data and utiUzation of these data during a 
mission; and detailed postflight analysis of tracking data to un- 
cover and resolve any anomalies. Separate articles treat tracking 
system improvements presently under consideration and error 
source reductions that may be realizable for future missions; 
solutions for deep space station locations; timing errors and polar 
motion; methods of correcting the tracking data for charged- 
particle effects (ionospheric corrections); and a model of tropo- 
spheric refraction. 

IVI40 The Mariner VI and VII Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendail, D. A. O'Handley, 

N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Muihall, 

V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 



221 



J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 

MULHOLLAND, J. D. 

M41 A Preliminary Special Perturbation Theory for tlie Lunar Motion 

K. Garthwaite, D. B. Holdridge, and J. D. Mulholland 

Technical Report 32-1517 (Reprinted from Astron. J., 
Vol. 75, No. 10, pp. 1133-1139, December 1970) 

For abstract, see Garthwaite, K. 

MULLER, P. M. 

M42 Tracking System Analytic Calibration Activities 
for the Manner Mars 1969 iViission 

B. D. Mulhali, C. C. Chao, N. A. Mottinger, P. M. Muller, 
V. J. Ondrasik, W. L Sjogren, K. L. Thuleen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 

For abstract, see Mulhali, B. D. 

M43 The Mariner VI and Vll Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhali, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 

MULLIN, J. V. 

M44 Basic Concepts in Composite Beam Testing 

J. V. Mullin (General Electric Company) and A. C. Knoeli 

Mater. Res. Stan., Vol. 10, No. 12, pp. 16-33, December 1970 

This article presents basic concepts relating to composite beam 
testing and the interpretation of test results. Both the short-beam 
and honeycomb-beam configurations are iovestigated under three- 



222 



and four-point loading. Interaction strength relations delineating 
the transition between flexural and shear failure are developed, 
and the effect of material property variations on these relations 
is shown. Associated beam displacement fields are analyzed to 
show the effect that shear deformation can have on materials 
characterization data and specimen design. Application is then 
made of the short-beam interaction relation to graphite epoxy 
test results. 



NAGLER, R. G. 

NOl Fabrication Development of Lightweight Honeycomb-Sandwich 
Structures for Extraterrestrial Planetary Probe Missions 

R. G. Nagler and R. A. Boundy 

Technical Report 32-1473, January 15, 1971 

Extraterrestrial planetary entry probes require new concepts in 
lightweight entry-vehicle design if the scientific payloads of 
missions are to be maximized. For a number of missions, com- 
munications and sensing requirements imply the need for an RF 
transparent aeroshell structure. Such an aeroshell would increase 
the view angle of the transmitters and receivers while providing 
equivalent protection from the entry environment. 

Presented are the results of an extensive study of lightweight 
resin-fiberglass honeycomb-sandwich structures that was per- 
formed to define the fabricability and economics of RF trans- 
parent structures and to provide design data for detail analysis. 
As part of this study, a comparison was made with lightweight 
adhesive-bonded aluminum honeycomb-sandwich structures so 
that any penalties for RF transparency could be established. The 
results showed that there was little difference in strength to 
weight in lightweight configurations for resin-fiberglass and 
aluminum honeycomb-sandwich structures. Aluminum showed 
some advantage in stiffness to weight, but resin fiberglass was 
easier and less expensive to fabricate and was adaptable to a 
wider range of aeroshell configurations. 



NEFF, D. E. 

N02 DSN Progress Report for November-December 1970: Tracking 
and Data Acquisition Elements Research: Polarization 
Diverse S-Band Feed Cone 

D. E. Neff and A. J. Freiley 

Technical Report 32-1525, Vol. I, pp. 66-72, 
February 15, 1971 



223 



Development of the polarization diverse S-band (PDS) feed cone 
that is used on the Mars Deep Space Station (DSS 14) 210-ft- 
diam antenna tricone is described. The PDS system integrates 
the knowledge gained in two previous feed system develop- 
ments and provides a highly flexible microwave front end. Right- 
handed circular polarization, left-handed circular polarization, 
and orthogonal linear polarizations are available on low-noise 
listen-only or diplexed channels. Additionally, a research and 
development radar capability for 500-kW continuous-wave power 
is provided. The system further provides manual or automatic 
servo tracldng of the position angle of received linear polariza- 
tion, which will be used for radio science purposes. 

N03 High-Power Feed Component Development 

F. E. McCrea, H. F. Reilly, Jr., and D. E. Neff 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. (I, pp. 64-68, November 30, 1970 

For abstract, see McCrea, F. E. 

NIGHTINGALE, D. 

N04 [GCF] High-Speed System Design Mark IIIA 

D. Nightingale 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 103-105, November 30, 1970 

The Deep Space Network systems selected high speed as the 
prime data transmission medium to fulfill the requirements of 
the multiple-mission support concept. This increase in traffic 
load, both into and out of the Space Flight Operations Facility, 
required substantial design changes to be made to the existing 
operational High-Speed System. This article describes the 
requirements, trade-offs, and plans that were used to develop 
the Mark IIIA design, including a bit-rate increase, expanded 
and improved interfaces, and demultiplexing techniques without 
deterioration in performance. All objectives of the design were 
met and the necessary equipment was installed and checked 
out in time to support Mariner Mars 1971 operations. 

NISHIKAWA, K. 

N05 Interaction Between an Electron Wave and an Ion Wave 
Due to Scattering by Electrons 

K. Nishikawa 

J. Phys. Sac. Japan, Vol. 29, No. 2, pp. 449-458, August 1970 



224 



Some basic properties of the coupling between an electron wave 
and an ion wave due to scattering by thermal electrons are com- 
pared with those of the coupling due to three-wave interactions. 
Using the kinetic wave equation which describes the relevant 
wave-particle interaction, the following three special problems 
are discussed in detail: 

(1) Effect of an enhancement of short-wavelength ion-wave fluc- 
tuations on the long-wavelength electron waves, 

(2) Effect of an enhancement of long-wavelength electron waves 
on the short-wavelength ion waves. 

(3) Effect of the beam-excited short-wavelength electron waves 
on the long-wavelength ion waves. 



NISHIMURA, T. 

N06 Spectral Factorization in Discrete Systems 

T. Nishimura 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 233-235, 
December 31, 1970 

The spectral factorization in discrete systems is studied in this 
article. Three theorems describing the solution and its character- 
istics are presented. A computer program incorporating this 
technique is applied to the orbit determination problem using 
the ranging system. 

NOGUCH!, H. 

N07 Electrical Properties of TCNQ Salts of lonene Polymers and 
Their Model Compounds 

V. Hadek, H. Noguchi, and A. Rembaum 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 192-198, 
December 31, 1970 

For abstract, see Hadek, V. 



NORTON, D. J. 

N08 Microwave Measurement of Solid Propellant Burning Rates 

D. J. Norton and A. L. Schultz 

Supporting Research and Advanced Development, 

225 



Space Programs Summary 37-65, Vol. Ill, pp. 163-167, 
October 31, 1970 

An experimental technique employing an X-band microwave sys- 
tem for continuous measurement of solid propellant burning 
rates is used to determine burning rates under conditions of 
rapid depressurization. The technique uses a microwave network 
analyzer to measure the phase shift of a microwave signal re- 
flected from the regressing propellant surface. 

NORTON, R. H. 

N09 Surveyor Final Report— Principal Scientific Results From 

the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames Research 
Center), J. W. Lucas, D. 0. Muhleman (California Institute of 
Technology), R. H. Norton, R. F. Scott (California Institute of 
Technology), E. M. Shoemaker (U.S. Geological Survey), 
R. H. Steinbacher, G. H. Sutton (University of Hawaii), and 
A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffe, L. D. 



O'BRIEN, P. F. 

001 Thermal Analysis System I: User's Manual 
J. A. Hultberg and P. F. O'Brien 
Technical Report 32-1416, March 1, 1971 
For abstract, see Hultberg, J. A. 

O'HANDLEY, D. A. 

002 The Mariner Vl and VU Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottlnger, P. M. Muller, C. C. Chao, B. D. Mulhali, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Bali, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 



226 



OHLSON, J. E. 

003 The Quasi-Stationary Coronal Magnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

C. T. Stelzried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison, (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), and 
J. M. Wilcox (University of California, Berkeley) 

Sol. Phys., Vol. 14, No. 2, pp. 440-456, October 1970 

For abstract, see Stelzried, C. T. 

OHTAKAY, H. 

004 In-Flight Calibration of a TV Instrument for 
Optical Spacecraft Navigation 

H. Ohtakay 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 97-100, 
October 31, 1970 

The results of an analytical investigation of the geometrical cali- 
bration of a navigation instrument during interplanetary flight 
are presented. The instrument, similar to a television camera, 
would view selected natural satellites and reference stars simul- 
taneously for navigating to the outer planets. An U X U reseau 
grid, etched onto the target raster of a vidicon tube, would be 
used to remove electromagnetic distortion from the satellite and 
reference star data to less than 1.2 arc sec (1 a). Fifty star images 
would be used to remove optical distortion to less than 4.3 arc sec 
(1 (t). Therefore, the use of the reseau grid and star images could 
enable the navigation measurements to be geometrically cali- 
brated to an accuracy of 5 arc sec (la). 

O'KEEFE, J. A. 

005 Surveyor Final Report— Lunar Theory and Processes: Discussion 
of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gauft (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 
H. Masursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 



227 



006 Surveyor Final Report— Lunar Theory and Processes: 
Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research- Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 
of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 
R. A. Phinney (Princeton University), and 

E. M. Shoemaker (U.S. Geological Survey) 

Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

For abstract, see Gault, D. E. 



ONDRASIK, V. J. 

007 Tracking System Analytic Calibration Activities 
for the Manner Wlars 1969 Mission 

B. D. Mulhall, C. C. Chao, N. A. Mottinger, P. M. Muiler, 
V. J. Ondrasik, W. L. Sjogren, K. L. Thuleen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 
For abstract, see Mulhall, B. D. 



008 DSN Progress Report for November-December 1970: A 
Cursory Examination of the Sensitivity of the Tropospheric 
Range and Doppler Effects to the Shape of the Refractivity 

Profile 

L F. Miller, V. J. Ondrasik, and C. C. Chao 

Technical Report 32-1526, Vol. I, pp. 22-30, February 15, 1971 

For abstract, see Miller, L. F. 

009 The Mariner VI and Vll Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muiler, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 



228 



OTOSHI, T. Y. 

010 Spacecraft Antenna Research: Further RF Study of Reflector 
Surface Materials for Spacecraft Antennas 

K. WooandT. Y. Otoshi 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 47-52, 
October 31, 1970 

For abstract, see Woo, K. 

Oil Improved RF Calibration Techniques: A Study of the RF 
Properties of the 210-ft-diam Antenna Mesh Material 

T. Y. Otoshi and R. B. Lyon 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 52-57, November 30, 1970 

This article describes a procedure for improving the accuracy 
of reflectivity loss meastirements on highly reflective mesh mate- 
rials. Through the use of the waveguide method and procedure 
described, the reflectivity losses of the 210-ft-diam antenna 
mesh material were measured to be 0.001 and 0.008 dB at 2295 
and 8448 MHz, respectively. The transmission losses were 
measured to be 43.1 dB at 2295 MHz and 30.5 dB at 8448 MHz. 
These results, however, are restricted to the equivalent free- 
space case where a linearly polarized plane wave is (1) obliquely 
incident on a very large sample of the 210-ft antenna mesh 
material, and (2) the E-field is normal to the plane of incidence. 

PACE, G. 

POl UBV: Subroutine to Compute Photometric Magnitudes 
of the Planets and Their Satellites 

G. Pace 

Technical Report 32-1523, February 15, 1971 

This computer subroutine computes the visual, blue, and ultra- 
violet photometric magnitudes of the planets, their natural satel- 
lites, and the sun at varying observation distances and phase 
angles. Currently available observational magnitude and phase 
function data are stored in the program and used in the compu- 
tation. 

P02 Subroutine To Compute Planet and Satellite 
Photometric Magnitudes 

G. Pace 



229 



Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, p. 96, 
October 31, 1970 

A computer subroutine has been developed to compute the visual, 
blue, and ultraviolet magnitudes of the planets, their satellites, 
and the sun at varying observation distances and phase angles. 
Currently available observational magnitude and phase function 
data are stored in the program and used in the computation. 

PASSELL, D. W. 

P03 DSN Progress Report for November-December 1970: 
Communications Control Group Assembly: Teletype 

Line Switching Equipment 

D. W. Passell 

Technical Report 32-1526, Vol. I, pp. 113-116, 
February 15, 1971 

This article describes the teletype portion of the communications 
control group assembly installed in the Ground Communications 
Facility's deep space station communications equipment sub- 
system. The functions, developmental status, and operational 
features of the teletype switching equipment are discussed, and 
the necessity for interfacing with a variety of communications 
common carriers is explained. 

P04 Communications Control Group Assembly Voice Data 
Switching Equipment 

D. W. Passell 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 111-113, November 30, 1970 

The transmission, monitoring, control, and distribution of voice 
and/or data audio frequencies are accomplished within the 
Deep Space Network through several interconnected Ground 
Communications Facility (GCF) subsystems and assembhes. This 
article describes the purpose, interfaces, development and status, 
and configuration of the voice data portion of the Communica- 
tions Control Group Assembly equipment installed at the GCF 
Deep Space Station Communications Equipment Subsystem. 



PATTERSON, R. E. 

P05 Development of a Long-Life High-Cycle-Life 
30 A-h Sealed AgO-Zn Battery 

R. E. Patterson 



230 



Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 69-72, 
October 31, 1970 

A two-phase program is under way to develop sealed AgO-Zn 
cells capable of performing 6-mo wet-charged stand during 
interplanetary travel plus an orbiting life of 100 or more 24-h 
cycles at 50% depth of discharge. Following 4 mo of charged 
stand (open-circuit voltage between 1.85 and 1.86 V), Phase I 
design 1 (utilizing wedge-shaped negative electrodes) and de- 
sign 2 (41% KOH group) completed 226 and 213 cycles, respec- 
tively, before the first cell failures occurred. The Phase I design 1 
cells containing 45% KOH completed 245 cycles without any 
failures. Phase II cells completed 9 mo of charged stand and are 
currently being cycle tested. 

PAWLIK, E. V. 

P06 Performance of a 20-cm-Diameter Electron-Bombardment 
Hollow-Cathode Ion Thruster 

E. V. Pawlik 

Technical Memorandum 33-468, February 15, 1971 

Experimental system studies on solar-electric primary propulsion 
for deep space probes are presently under way at the Jet Pro- 
pulsion Laboratory. These studies are performed with a 20-cm- 
diameter electron-bombardment ion thruster. The electron emitter 
used to create the thruster plasma has been changed from an oxide 
to a hollow cathode type in order to improve thruster efficiency 
and lifetime. The performance of this modified thruster is de- 
tailed over a wide range of variations in thruster parameters. 
Thruster output power can be varied from 1000 to 2600 W. 

P07 Ion Thruster Electron Baffle Sizing 

E. V. Pawlik 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 201-203, 
December 31, 1970 

This article presents the results of an experimental investigation 
that was undertaken to examine the effects of changing the 
diameter of the electron baffle on ion thruster performance. 
This baffle is located within the thruster near the hollow cathode 
and serves to distribute electrons emitted into the arc chamber. 
Four baflSe sizes were investigated. A minimum diameter was 
found below which poor thruster throttling properties and noisy 
arc chamber operation would result. 



231 



P08 An lofi Thruster Utilizing a Combination Keeper Electrode and 

Electron Baffle 

E. V. Pawlik 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 204-206, 

December 31, 1970 

This article presents the results of an experimental investigation 
that was undertaken to examine the effects on ion thruster per- 
formance of operating with a combination keeper electrode and 
electron bafifle. These items are usually present in thrusters 
employing hollow cathodes and serve to maintain the cathode 
discharge and distribute electrons into the arc chamber. No 
improvement in the level of arc chamber losses was noted. A 
reduction in arc current oscillations under certain thruster oper- 
ating conditions was observed. 



PEAVLER, P. F. 

P09 DSN Progress Report for November-December 1970: 
Inbound High-Speed and Wideband Data Synchronizers 

P. F. Peavler 

Technical Report 32-1526, Vol. I, pp. 93-94, February 15, 1971 

The Space FHght Operations Facility (SFOF) high-speed and 
wideband data synchronizers accept serial, blocked, digital data 
from the Ground Communications Facihty. These synchronizers 
establish synchronization, detect and delete filler blocks, perform 
serial-to-parallel conversion, and output these data to two IBM 
360/75 computers. Their functional characteristics, input, syn- 
chronization, conversion, and output are described in this 
article. 



PERKINS, G. S. 

PIO TOPS Attitude-Control Single-Axis Simulator 

J. D. Ferrera and G. S. Perkins 

Supporting Research and Advanced Developnient, 
Space Programs Summary 37-65, Vol. Ill, pp. 118-119, 
October 31, 1970 

For abstract, see Ferrera, J. D. 



232 



PERLMAN, M. 

PI 1 The Decomposition of the States of a Linear Feedback 
Shift Register Into Cycles of Equal Length 

M. Perlman 

Technical Report 32-1511 (Reprinted from IEEE Trans. 
Computers, Vol. C-19, No. 11, pp. 1029-1035, November 1970) 

This article presents a derivation of a linear feedback function 
for an r-stage feedback shift register that results in branchless 
cycles of equal length. The linear recurrence relationship and 
generating function, which characterize the r-stage feedback 
shift register's behavior, are used to prove that both of the 2'' 
states lie in cycles of equal length. 

P12 The Implementation of m-ary Linear Feedback Shift 
Registers With Binary Devices 

M. Perlman 

SupporVmg Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 161-163, 
December 31, 1970 

An m-ary linear feedback shift register (LFSR) is first decom- 
posed into p-ary parallel LFSRs where each p is a distinct prime 
factor of the integer m. The states of each p-ary LFSR, where 
p > 2, are coded in binary and unspecified states are treated 
optionally. For a given p, a total of n binary shift registers with 
interdependent binary feedback functions, where 2"-^ < p < 
2", are used in the implementation of the p-ary LFSR. 



PHILLIPS, H. 

P13 Hydrostatic Bearing Runner Level Reference 

G. Gale and H. Phillips 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 80-83, November 30, 1970 

For abstract, see Gale, G. 

PHINNEY, R. A. 

P14 Surveyor Final Report— Lunar Theory and Processes: 
Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gault (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 



233 



H. Masursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

The central scientific questions about the moon that might be 
answered by chemical compositional data are: 

(1) What is the bulk composition of the moon? How does this 
compare with the composition of the earth and the meteorites? 

(2) What are the composition and mode of origin of the lunar 
crust? Is it derived in ways similar to the terrestrial crust? 

(3) What is responsible for the known differences between high- 
lands and maria, e.g., the differences in albedo, elevation, and 
crater numbers? 

Preliminary results from the alpha-scattering experiment on 
Surveyors V, VI, and VII are described in this article. Among 
the subject discussed are contrasts in albedo, estimated density 
of lunar surface rocks, bulk composition of the moon, the thermal 
regime in the moon, chondritic meteorites and the moon, tektites, 
and solar system implications. 

P15 Surveyor Final Report— Lunar Theory and Processes: 
Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 
of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 
R. A. Phinney (Princeton University), and 

E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

For abstract, see Gault, D. E. 



PRICE, T. W. 

P16 High-Thrust Throttleable Monopropellant Hydrazine Reactors 

T. W. Price 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 213-221, 

December 31, 1970 

Two series of subscale throttling tests, using surplus Mariner 
Mars 1969 catalytic reactors, were conducted. Rapid dynamic 
throttling of a monopropellant hydrazine/Shell-405 catalytic 
decomposition chamber was demonstrated, and the performance 



234 



of the reactor was measured. Heat sterilization of a catalytic 
reactor was also shown to have no significant deleterious effects, 
although measurable differences in the reactor start transient 
characteristics were noted. 



RAHEB, M. E. 

ROl Effect of Elastic End Rings on the Eigenfrequencies 
of Finite Length Thin Cylindrical Shells 

M. E. Raheb 

Technical Report 32-1489, March 1, 1971 

The effect of elastic end rings on the eigenfrequencies of thin 
cylindrical shells was studied by using an exact solution of the 
linear eigenvalue problem. The in-plane boundary conditions 
which proved to be very influential in the neighborhood of the 
minimum frequency were exactly satisfied. The out-of -plane and 
torsional rigidities of the ring were found to govern the overall 
shell stiffness. Considerable mode interaction was noticed at 
low circumferential wave numbers for low values of the ring 
stiffness. 

Rings with closed section were found to be more efficient than 
those with open section for the same values of weight ratio. No 
appreciable difference was noticed between rings fixed from the 
inside or the outside of the shell mid-surface. 



REICHLEY, P. E. 

R02 Observations of Interstellar Scintillations of Pulsar 
Signals at 2388 MHz 

G. S. Downs and P. E. Reichley 

Astrophys. J., Vol. 163, No. 1, Ft. 2, pp. L11-L16, 
January 1, 1971 

For abstract, see Downs, G. S. 



REID, M. S. 

R03 Improved RF Calibration Techniques: System Operating Noise 
Temperature Calibrations of Low Noise Cones 
[September-October 1970] 

M. S. Reid 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 57-61, November 30, 1970 



235 



The system operating noise temperature performance of the 
low noise cones in the Goldstone Deep Space Communications 
Complex is reported for the period June 1 through September 
30, 1970. The operating noise' temperature caUbrations were per- 
formed using the ambient termination technique. Averaged oper- 
ating noise temperature calibrations for the S-band polarization 
ultra cone, S-band research operational cone, and S-band Cas- 
segrain ultra cone are presented. Preliminary noise temperature 
data of the polarization diversity S-band cone are also included. 



REILLY, H. F., JR. 

R04 High-Power Feed Component Development 

F. E. McCrea, H. F. Reilly, Jr., and D. E. Neff 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 64-68, November 30, 1970 

For abstract, see McCrea, F.E. 

R05 S-Band Polar Ultra Cone Improvement 

H. F. Reilly, Jr., and F. E. McCrea 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, p. 69, November 30, 1970 

This article presents the results of recent work performed on 
standard Deep Space Instrumentation Facility 2-position S-band 
switches to improve insertion loss, isolation, and the voltage 
standing-wave ratio. Improved choke design using standard 
stators and rework rotors to improve performance was successful in 
lowering system noise temperature and increasing needed isola- 
tion in a new feed cone design. 

REINBOLD, S. J. 

R06 The Manner VI and Vll Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handiey, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhali, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 
For abstract, see Gordon, H. J. 



236 



REMBAUM, A. 

R07 Energy Transfer in Bipyridilium (Paraquat) Salts 

A. Rembaum, V. Hadek, and S. P. S. Yen 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 189-191, 
December 31, 1970 

Bipyridils quaternized by means of mineral acids and reacted 
with LiTCNQ exhibit an anomalously high electronic conduc- 
tivity. This phenomenon is not observed when the quaternization 
is carried out by means of alkyl halides. Examination of electri- 
cal and optical properties of several bipyridilium TCNQ Salts 
revealed an electron transfer from the radical ion to the paraquat. 
The postulated mechanism of electron transfer involves the for- 
mation of a hydrogen atom and a neutral TCNQ molecule. 

R08 Electrical Properties of TCNQ Salts of lonene Polymers 
and Their Mode! Compounds 

V. Hadek, H. Noguchi, and A. Rembaum 

Supporting Researcti and Advanced Developnnent, 
Space Programs Summary 37-66, Vol. Ill, pp. 192-198, 
December 31, 1970 

For abstract, see Hadek, V. 



RENZETTI, N. A. 

R09 DSN Progress Report for November-December 1970: DSN 
Functions and Facilities 

N. A. Renzetti 

Technical Report 32-1526, Vol. I, pp. 1-3, February 15, 1971 

The objectives, functions, and organization of the Deep Space 
Network (DSN) are summarized. The Deep Space Instrumenta- 
tion Facility, the Ground Communications Facility, and the 
Space Flight Operations Facility are described. 

RIO Tracking and Data System Support for the Pioneer Project: 
Pioneer VI. Extended Mission: July 1, 1966-Juiy 1, 1969 

N. A. Renzetti 

Technical Memorandum 33-426, Vol. V, February 1, 1971 

The Pioneer VI mission (inward trajectory, heliocentric orbit) 
employed six scientific instruments to accumulate information 



237 



relative to interplanetary high-energy particles, solar phenomena, 
and plasma. The tracking of the spacecraft also made possible 
the support of a celestial mechanics experiment based on the 
radio metric data generated by the Deep Space Network. The 
network provided support for all of the science and engineering 
telemetry data return and transmission of commands to the 
spacecraft. 



RINDERLE, E. A. 

Rll DSN Progress Report for November-December 1970: Choice 
of Integrators for Use With a Variation-of-Parameters 

Formulation 

T. D. Talbot and E. A. Rinderle 

Technical Report 32-1526, Vol. I, pp. 117-121, 
February 15, 1971 

For abstract, see Talbot, T. D. 



RODEMICH, E. 

R12 A Real Variable Lemma and the Continuity of Paths of 
Some Gaussian Processes 

A. M. Garsia, E. Rodemich, and H. Rumsey, Jr. 

Ind. Univ. Math. J., Vol. 20, No. 6, pp. 565-578, 
December 1970 

For abstract, see Garsia, A. M. 



ROPER, W. D. 

R13 Spacecraft Adhesives for Long Life and Extreme Environment 

W. D. Roper 

Supporting Researcti and Advanced Development, 
Space Programs Summary 37-66, Vol. Ml, pp. 111-1 14, 
December 31, 1970 

A laboratory evaluation was performed on several high per- 
formance adhesive materials in order to establish their suitability 
for future spacecraft appMcation. The adhesive materials tested 
included the polyimide, polybenzimidazole, and polyquinoxaline 
polymers. In this evaluation, the thermal shock resistance of each 
adhesive was determined by thermal cycling through the tem- 
perature range of +400 to — 100°F. The mode of cychng was 
typical of what might be required of adhesives in future plane- 
tary missions. The order of decreasing preference of the adhe- 



238 



sives for future spacecraft application was found to be: polyimide, 
polyquinoxaline, and polybenzimidazole. Additional long-term 
elevated-temperature aging tests are underway to further charac- 
terize the materials as spacecraft adhesives. 



ROSCHKE, E. J. 

R14 Heat Transfer From Partially Ionized Argon Flowing in 
a Conducting Channel With an Applied, Transverse 
Magnetic Field 

E. J. Roschke 

Technical Report 32-1510, December 15, 1970 

Wall heat transfer measurements were obtained for laminar flow 
of partially ionized argon flowing in a square channel with and 
without an applied, transverse magnetic field. Tests were con- 
ducted for subsonic flows and for flows that were supersonic 
before a magnetic field was applied. Principal results are 
presented in terms of the Stanton number. The Stanton number 
increased by a factor of as much as six at the highest magnetic 
field strengths available (nearly 10 kG) over results observed at 
zero field. Heat transfer and flow data were used to estimate the 
effective values of the Joule heating parameter, the Hall coeffi- 
cient, the Hartmann number, and the current density; these 
values appeared to be physically realistic. It is believed that the 
large increases in heat transfer observed with an applied mag- 
netic field were due to (1) a small but sufficient amount of Joule 
heating, which caused significant changes in the temperature 
distribution, augmented or accompanied by (2) magnetically 
induced nonequilibrium ionization. These results represent the 
only known experimental measurements obtained thus far for 
heat transfer from a partially ionized gas in steady internal flow 
with an applied, transverse magnetic field. 

ROSENTHAL, L. A. 

R15 Terminated Capacitor Discharge Firing of 
Electroexplosive Devices 

L. A. Rosenthal (Rutgers University) and V. J. Menichelli 

Technical Report 32-1521, February 15, 1971 

By terminating the discharge of energy into an insensitive elec- 
troexplosive device, firing energy parameters can be determined. 
A simple capacitor discharge system providing exponential pulses 
terminated at an adjustable width is described. Development 
technique and application to testing are discussed. 



239 



ROUKLOVE, P. 

R16 Thermoelectric Generators for Deep Space Application 

P. Rouklove and V. Truscello 

Technical Report 32-1495, January 15, 1971 

To provide a source of electrical energy independent of the sun 
for use in unmanned spacecraft investigation of the outer planets, 
JPL is evaluating radioisotope thermoelectric generators. Criteria 
for the selection of the thermoelectric materials, the design of the 
generator, and its integration with the spacecraft are discussed. 
Results of the tests of 10 generators that have been, or are pres- 
ently, under test at JPL are also presented. 

RUBINSTEIN, R. 

R17 The DSN User Requirements Forecast 

R. Rubinstein 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 144-145, November 30, 1970 

The DSN User Requirements Forecast has been adopted as the 
single source for project information by all Deep Space Netvs^ork 
(DSN) planning and systems engineering personnel. This article 
describes the development and composition of the Requirements 
Forecast and illustrates how the compiled data can be used to 
plan for future requirements imposed on the DSN. 

RUMSEY, H., JR. 

R18 Decoding and Synchronization Research: Euler Products, 

Cyclotomy, and Coding 

R. McEliece and H. Rumsey, Jr. 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 22-27, 
October 31, 1970 

For abstract, see McEliece, R. 

R19 A Real Variable Lemma and the Continuity of Paths of 
Some Gaussian Processes 

A. M. Garsia, E. Rodemich, and H. Rumsey, Jr. 

Ind. Univ. IVIath. J., Vol. 20, No. 6, pp. 565-578, 
December 1970 

For abstract, see Garsia, A. M. 



240 



RUNG, R. B. 

R20 DSN Status Code 

R. B. Rung and L. W. Miller 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 141-143, November 30, 1970 

The Deep Space Network (DSN) Status Code provides an auto- 
mated display of the current status of DSN support organized 
by both deep space station and spacecraft. Information is 
derived from the DSN Monitor System on the configuration and 
quality of the data flow for each DSN system. A display will be 
driven which indicates on a 0-9 scale the support status of 
each DSN system or facility, with a 9 being proper system 
performance, lesser numbers indicating partial failures, and a 
indicating that the system is not scheduled. 

RUSCH, W. V. T. 

R21 The Quasi-Stationary Coronal IVIagnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

C. T. Stelzried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison, (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), and 
J. M. Wilcox (University of California, Berkeley) 

Sol. Phys., Vol. 14, No. 2, pp. 440-456, October 1970 

For abstract, see Stelzried, C. T. 



RUSSELL, R. K. 

R22 The Use of Sequential Estimation With Process Noise for 
Processing DSN Tracking Data During Planetary Orbiter 
Missions 

R. K. Russell 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 14-22, November 30, 1970 

Much experience with orbiter state estimation and prediction 
based on the "batch" least-squares method has been accumulated. 
During the Lunar Orbiter missions, severe problems were experi- 
enced with the batch filter operating in a real-time operations 
mode. Since these problems arose due to gravitational perturba- 
tions, there is the distinct possibility similar problems will exist 
for the Mariner Mars 1971 orbiter phase. To circumvent some 
of the problems associated with the batch filter operating in the 



241 



presence of gravitational perturbations, the sequential data filter, 
incorporating process noise, is considered. The inclusion of an 
appropriately chosen process noise may obviate the need to solve 
for harmonics in real-time while providing a more accurate 
state estimate than that of the batch filter. In addition, this filter 
seems to eliminate the problem of "optimum data spans" as 
additional data does not degrade the state estimate. 



SABELMAN, E. E. 

SOI TOPS Mechanical Devices 

E. E. Sabelman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 148-156, 

December 31, 1970 

This article summarizes the development of three mechanical 
devices for the Thermoelectric Outer-Planet Spacecraft (TOPS). 
These devices include the radioisotope thermoelectric generator 
and science boom actuator-damper, the magnetometer boom, 
and the regenerative pump for the TOPS fluid loop. The design 
and functional characteristics of each device are given and test 
procedures and results of test models are included. 



SATO, T. 

S02 Radio Science Support [by DSN, September-October 1970] 

T. Sato, L. Skjerre, and D. Spitzmesser 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 151-153, November 30, 1970 

This article presents a summary of radio science operations at 
Deep Space Network facilities during the period September 1 to 
October 31, 1970. Activities of the Radio Astronomy Experiment 
Selection Panel are also included. 

303 The Quasi-Stationary Coronal Magnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

C. T. Stelzried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison, (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), and 
J. M. Wilcox (University of California, Berkeley) 

Sol. Phys., Vol. 14, No. 2, pp. 440-456, October 1970 

For abstract, see Stelzried, C. T. 



242 



SCHATTEN, K. H. 

504 The Quasi-Stationary Coronal Magnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

C. T. Stelzried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison, (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), and 
J. M. Wilcox (University of California, Berkeley) 

Sol. Phys., Vol. 14, No. 2, pp. 440-456, October 1970 

For abstract, see Stelzried, C. T. 

SCHLOSS, A. 

505 Capacitance of Solar Cells and Panels Under 
Various Load Conditions 

A. Schloss 

Technical Memorandum 33-464, February 1, 1971 

Associated with a solar cell is a diflFusion capacitance that is 
directly proportional to the short circuit current capability of 
the cell. If one attempts to measure the maximum power capa- 
bility of a cell or panel by a sweep-loading technique, the 
current provided by the diffusion capacitance will affect the 
measurement. In order to reduce the error thus introduced to 
acceptable levels, the magnitude of the diffusion capacitance 
must be known. This report presents values one can expect as 
well as a measurement technique to determine capacitance of 
cells of various manufacture. 

SCHORN, R. A. J. 

806 High-Dispersion Spectroscopic Observations of Venus: IX. The 
Carbon Dioxide Bands at 12,030 and 12,177 A 

L D. G. Young, R. A. J. Schorn, and H. J. Smith (University 
of Texas) 

Icarus: Int. J. Sol. Sys., Vol. 13, No. 1, pp. 74-81, July 1970 

For abstract, see Young, L. D. G. 

S07 Improved Constants for the 7820 A and 7883 A Bands of CO2 

L. D. G. Young, A. T. Young, and R. A. Schorn 

J. Quant. Spectrosc. Radiat. Transfer, Vol. 10, No. 12, 
pp. 1291-1300, December 1970 

For abstract, see Young, L. D. G. 



243 



SOS Improved Solar Wavelengths Between 7780 and 7925 A 

A. T. Young and R. A. Schom 

Sol. Phys., Vol. 15, No. 1, pp. 97-101, November 1970 

For abstract, see Young, A. T. 

SCHULTZ, A. L. 

509 Microwave Measurement of Solid Propellant Burning Rates 

D. J. Norton and A. L. Schultz 

Supporting Research and Advar)ced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 163-167, 
October 31, 1970 

For abstract, see Norton, D. J. 

SCOTT, R. F. 

510 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. IVI. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gauit (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see JafFe, L. D. 

SCULL, J. R. 

511 Mariner Mars 1969 Navigation, Guidance and Control 
J. R. Scull 

Automatica, Vol. 6, No. 5, pp. 755-766, November 1970 

Design, mechanization, and flight test results of the Mariner 
Mars 1969 navigation, guidance, and control systems are dis- 
cussed. A trajectory design section describes the near-earth 
launch trajectory and planetary targeting and constraints, as well 
as the tradeoffs made on the trajectory selection. Among the 
factors considered are reliability, direct ascent vs. parking orbit, 
and higher spacecraft weight vs. extended launch window. Guid- 



244 



ance and orbit determination factors are discussed, including 
earth-based radio and spacecraft optical navigation and the 
accuracy of orbit determination and maneuver execution. 

The control systems section identifies differences in the atti- 
tude control, midcourse maneuver, and science instrument scan 
pointing systems from those used in previous Mariner spacecraft. 
A description is given of the new central computer and 
sequencer system, used for the first time on this mission, which 
allows extremely flexible spacecraft operation using in-flight 
reprogramming of the computer memory by radio command. 

Finally, reHability summaries and performance evaluations per- 
mit conclusions as to the effectiveness of the Mariner Mars 1969 
navigation, guidance, and control systems to conduct near-term 
and more advanced planetary missions. 

SEIDEL, B. 

512 Improved RF Calibration Techniques: PDS Cone Waveguide/ 
Poiarimeter Calibrations 

P. D. Batelaan, B. Seidel, and R. B. Lyon 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 61-63, November 30, 1970 

For abstract, see Batelaan, P, D. 

SHALLBETTER, A. C. 

513 Block IV Receiver-Exciter Development 

H. Donnelly, A. C. Shallbetter, and R. E. Waller 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 115-124, November 30, 1970 

For abstract, see Donnelly, H. 

SHAW, D. T. 

814 Theoretical Considerations of the Prebreakdown Characteristics 
in a Cesium Thermionic Discharge 

D. T. Shaw 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 101-104, 
October 31, 1970 

The transition from the electron-rich, unignited mode to the 
ignited mode of cesium thermionic diodes is considered analyti- 



245 



cally. Although a number of experimental results on cesium 
ignition have been reported, the theoretical understanding of the 
potential distribution in the collector sheath, that was found to 
be correlated with the ignition, has been limited. 

This article attempts to analyze this potential in the sheath hav- 
ing a finite thickness. Most analyses have been made on the 
assumption of infinitesimal thickness. The new analysis is formu- 
lated on the assuanption that, in the prebreakdown region, the 
Debye length is of the same order of magnitude as the electron 
mean-free-path. Thus, the collector sheath region, within which 
most of the potential drop takes place in the pre-ignition con- 
dition of the diode, cannot be treated as coUisionless. Based upon 
the collision-dominated model, the voltage drop and the electric 
field in the collector sheath was calculated. Since the field in- 
tensity in the sheath was determined as a function of voltage 
applied to the cesium diode, a rate of cesium ionization that 
accounts for the diode ignition is now calculable. 



SHIMADA, K. 

S15 Optimization and Reliability Calculations for Multi- 
Thermionic-Converter Systems 

R. Szejn and K. Shimada 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 76-80, 

December 31, 1970 



For abstract, see Szejn, R. 



SHOEMAKER, E. M. 

S16 Surveyor Final Report— Principal Scientific Results From 

the Surveyor Program 



L. D 



Jaffe, C. 0. Alley (University of Maryland), 



S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhieman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus; Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffe, L. D. 



246 



517 Surveyor Fina! Report— Geology: Craters 

E. C. Morris (U.S. Geological Survey) and 
E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 157-172, 211-212, 
March 1970 

For abstract, see Morris, E. C. 

518 Surveyor Final Report— Geology: Fragmental Debris 

E. C. Morris (U.S. Geological Survey) and 
E. M. Shoemaker (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 173-187, 211-212, 
March 1970 

For abstract, see Morris, E. C. 

519 Surveyor Final Report— Geology: Physics of Fragmental Debris 

E. M. Shoemaker (U.S. Geological Survey) and 
E. C. Morris (U.S. Geological Survey) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 188-212, 
March 1970 

The size-frequency distribution of the resolvable fragments on 
the lunar surface was studied at each of the five Surveyor land- 
ing sites by choosing sample areas near the spacecraft so that 
the resolution and area covered would provide particle counts 
spanning different, but overlapping, parts of the particle size 
range. Studies were made of the parts of the surface undisturbed 
by the spacecraft at each site. Sample areas were selected that 
appeared to be representative of the areas surrounding the space- 
craft; areas that appeared to have anomalously high or anomal- 
ously low particle abundances were avoided. The fragmental 
material disturbed by the footpads of the spacecraft during land- 
ing also was studied at some sites, and special studies were made 
at the Surveyor III landing site of the size distribution of the 
fragmental debris in the strewn fields of blocks surrounding 
craters with raised rims. The results of these studies and con- 
clusions that may be drawn concerning the physics of fragmental 
debris are reported in this article. 

520 Surveyor Final Report— Lunar Theory and Processes: 
Discussion of Chemical Analysis 

R. A. Phinney (Princeton University), D. E. Gault (Ames 
Research Center), J. A. O'Keefe (Goddard Space Flight Center), 
J. B. Adams, G. P. Kuiper (University of Arizona), 



247 



H. Masursky (U.S. Geological Survey), E. M. Shoemaker (U.S. 
Geological Survey), and R. J. Collins (University of Minnesota) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 213-223, 
March 1970 

For abstract, see Phinney, R. A. 

S21 Surveyor Final Report— Lunar Theory and Processes: 
Post-Sunset Horizon "Afterglow" 

D. E. Gault (Ames Research Center), J. B. Adams, 

R. J. Collins (University of Minnesota), G. P. Kuiper (University 
of Arizona), J. A. O'Keefe (Goddard Space Flight Center), 
R. A. Phinney (Princeton University), and 

E. M, Shoemaker (U.S. Geological Survey) 

fcarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 230-232, 
March 1970 

For abstract, see Gault, D. E. 



SHULMAN, G. P. 

522 Isolation and Characterization of Coal in Antarctic 
Dry-Valley Soils 

A. J. Bauman, E. M. Bollin, G. P. Shulman, and R. E. Cameron 

Antarc. J. U.S., Vol. V, No. 5, pp. 161-162, 
September-October 1970 

For abstract, see Bauman, A. J. 

SIEGMETH.A.J. 

523 Pioneer Mission Support [by DSN, September-October 1970] 

A. J. Siegmeth 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 4-11, November 30, 1970 

The continuation of the tracking and data acquisition support 
of the still active Pioneer VI, VII, VIII, and IX missions is pre- 
sented. The quantitative and qualitative assessment of the Deep 
Space Network support is given. The data return -was enhanced 
by the near-optimum-type utilization of the 85-ft antenna sta- 
tions. A summary of the Pioneer F and G mission support 
planning activities is given with emphasis on the telecommunica- 
tions link design and its interfaces. These missions, to be 
launched in 1972 and 1974, will provide the first closeup 
reconnaissance of Jupiter. 



248 



SILVER, R. H. 

524 Evaluation of Spacecraft Wlagnetic Recording Tapes 
and Magnetic Heads [August-September 1970] 

S, H. Kalfayan, R. H. Silver, and J. K. Hoffman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 168-171, 
October 31, 1970 

For abstract, see Kalfayan, S. H. 

525 Evaluation of Recording Tape and Heads for Spacecraft 
Magnetic Tape Recorder Applications 
[October-November 1970] 

J. K. Hoffman, S. H. Kalfayan, and R. H. Silver 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, p. 150, 
December 31, 1970 

For abstract, see Hoffman, J. K. 

526 Evaluation of Magnetic Recording Tapes: A Method for the 
Quantitative Determination of Stick-Slip 

R. H. Silver, S. H. Kalfayan, and J. K. Hoffman 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. HI, pp. 198-200, 
December 31, 1970 

A method is described to measure "stock-slip" that is manifested 
in magnetic recording tapes. It consists of determining the appar- 
ent period of a prerecorded signal on the test tape. As the speed 
of the tape varies with stick-slip, the 'cycle period of the signal 
will also vary. The extent of the variation of the period from its 
initial value will, therefore, be a measure of stick-slip. 



SIMON, H. S. 

S27 DSN Progress Report for November-December 1970: SFOF 
Mark illA Central Processing System Mode! Development 

H. S. Simon 

Technical Report 32-1526, Vol. I, pp. 95-102, 
February 15, 1971 

Simulation models are currently being used for Space Flight 
Operations Facility (SFOF) development at the Jet Propulsion 
Laboratory. The results of two modeling studies are described 



249 



that were performed during the early stages of the SFOF 
Mark IIIA central processing system development. 

528 Functional Design of the Space Flight Operations Facility for 

the 1970-1972 Era 

H. S. Simon 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 90-94, November 30, 1970 

The overall design of the Mark IIIA Space Flight Operations 
Facility is described in general terms. Systems and subsystems 
are identified, and new capabilities are listed. Also identified 
are interfaces with the Ground Communications Facility and the 
Scientific Computing Facility. 

SIMON, M. K. 

529 On the Stability of Second-Order Tracking Loops With 

Arbitrary Time Delay 

M. K. Simon 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 50-53, 

December 31, 1970 

The introduction of data-aided loops has increased problems in 
loop stability due to the presence of a delay element in the 
open-loop transfer function. This delay, which is ideally equal 
to the reciprocal of the data rate, will cause instability problems 
at sufficiently low data rates. This article approaches the general 
question of second-order tracking loop stability in the presence 
of arbitrary time delay. A specific application of the results 
yields an approximate answer to the question of how low in data 
rate one can go before the data-aided loop becomes unstable. 
The principal tool used in the linear stability analysis is the 
Nyquist diagram as applied to the open-loop, noise-free, transfer 
function of a generafized second-order tracking loop. For non- 
linear stability performance, a method based on an approxi- 
mation to the phase-plane behavior is used. 

530 The Steady-State Performance of a Data-Transition Type of 
First-Order Digital Phase-Locked Loop 

M. K. Simon 

Supporting Research and Advanced Developnient, 
Space Programs Summary 37-66, Vol. Ill, pp. 59-68, 
December 31, 1970 



250 



A fully suppressed carrier data-aided carrier tracking loop and 
attendant data detector have been implemented recently and 
proposed for possible application to future planetary spacecraft 
programs, communication satellites, and the Manned Space 
Station. One of the significant advantages of the proposed data- 
aided receiver is its ability to give satisfactory tracking (phase- 
noise) and bit error probability performance in the presence 
of a coarse estimate of bit sync timing. In this article, the 
development of a mathematical model is given which describes 
the coarse bit synchronizer used in the data-aided receiver, and 
its steady-state performance is analyzed. The behavior and 
performance of the bit synchronizer itself is also included. 

531 Optimum Modulation Index for a Data-Aided, Phase-Coherent 
Communication System 

M. K. Simon 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. HI, p. 69, 
December 31, 1970 

Results were presented in Space Programs Summary 37-63, 
Vol. Ill, for optimally choosing a modulation factor for a data- 
aided, phase-coherent communication system. This article is an 
addendum to that previous article, giving updated information 
and an erratum to an incorrect equation. 

532 The Effect of Loop Stress on the Performance of 
Phase-Coherent Communication Systems 

W. C. Lindsey (University of Southern California) and 
iVI. K. Simon 

IEEE Trans. Commun. Technol., Vol. COiVi-18, No. 5, 
pp. 569-588, October 1970 

For abstract, see Lindsey, W. C. 

533 Nonlinear Analysis of an Absolute Value Type of an Early-Late 
Gate Bit Synchronizer 

iVI. K. Simon 

IEEE Trans. Commun. Techno/., Vol. COM-IS, No. 5, 
pp. 589-596, October 1970 

The steady-state phase noise performance of an absolute value 
type of early-late gate bit synchronizer is developed using the 
Fokker-Planck method. The results are compared with the per- 



251 



formance of two other commonly used bit synchronizer circuit 
topologies on the basis of either: (1) equal equivalent signal to 
noise in the loop bandwidth in the Hnear region, or (2) equal 
loop bandwidth at each input signal-to-noise ratio Rg- These 
comparisons are made as a function of R,. In both cases, the 
absolute value type of early-late gate yields the best performance 
(in the sense of minimum phase noise) at every value of Rs- 

S34 Optimization of the Performance of a Digital-Data-Transition 

Tracking Loop 

M. K. Simon 

IEEE Trans. Commun. Techno!., Vol. COM- 18, No. 5, 
pp. 686-689, October 1970 

The steady-state behavior of a data-transition tracking loop, 
used as a bit synchronizer in a phase-coherent receiver, is con- 
sidered. Optimization of mean-square phase noise and mean 
time to first cycle slip is performed when the average power of 
the reference cross-correlating signal is constrained. It is shown 
that by adjusting the quadrature channel gain along with the 
integration interval, a significant improvement in phase noise 
and cycle slip performances can be achieved over that system 
which integrates in the quadratxire channel over the full symbol 
period. All the results are derived for a first-order loop filter 
merely to indicate the approach to the problem and the relative 
value of optimizing the system. 



SJOGREN, W. L 

535 Tracking System Analytic Calibration Activities 
for the Manner Mars 1969 Mission 

B. D. Mulhali, C. C. Chao, N. A. Mottinger, P. M. Muller, 

V. J. Ondrasik, W. L. Sjogren, K. L. Thuleen, and D. W. Trask 

Technicai Report 32-1499, November 15, 1970 
For abstract, see MulhaU, B. D. 

SKJERRE, L 

536 Radio Science Support [by DSN, September-October 1970] 

T. Sato, L. Skjerre, and D. Spitzmesser 

The Deep Space Network, Space Progranns Summary 37-66, 
Vol. II, pp. 151-153, November 30, 1970 

For abstract, see Sato, T. 



252 



SMITH, H. J. 

537 High-Dispersion Spectroscopic Observations of Venus: IX. The 
Carbon Dioxide Bands at 12,030 and 12,177 A 

L. D. G. Young, R. A. J. Schorn, and H. J. Smith (University 
of Texas) 

Icarus: Int. J. Sol. Sys., Vol. 13, No. 1, pp. 74-81, July 1970 
For abstract, see Young, L. D. G. 

SMITH, L S. 

538 TOPS Attitude-Control Single-Axis Simulator 
True Position Encoder 

W. C. Goss and L S. Smith 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 119-121, 
October 31, 1970 

For abstract, see Goss, W. C. 



SPITZMESSER, D. 

539 Radio Science Support [by DSN, September-October 1970] 

T. Sato, L. Skjerre, and D. Spitzmesser 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 151-153, November 30, 1970 

For abstract, see Sato, T. 

STAfSITON, R. H. 

540 Approach Guidance Subsystem Development 

R. H. Stanton 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 107-111, 
October 31, 1970 

An approach guidance sensor subsystem for multiplanet missions 
is being developed based on a satellite-star mapping concept. An 
on-board sensor provides maps of natural satellite motion ref- 
erenced to fixed background stars which are then used to provide 
accurate trajectory estimates. Two separate approaches are being 
followed in developing this subsystem. The first, which uses 



253 



science cameras for all guidance measurements, is only briefly 
discussed. The main emphasis o£ this summary relates to the 
second approach, the development of a separate approach guid- 
ance sensor. The basic elements of a proposed sensor subsystem 
(optics, image intensifier, and image readout device) are briefly 
described. An important recent development is the inclusion of 
a channel plate image intensifier as a principal component of the 
system. Its effectiveness in solving the critical sensitivity and 
dynamic range problems is described, followed by a discussion 
of several alternate image readout devices. 

STAFFER, G. 

541 Evaluation of a SNAP- 19 TAGS Thermoelectric Generator 

G. Stapfer 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 65-67, 
October 31, 1970 

The performance of a SNAP-19 (System for Nuclear Auxfliary 
Power 19) thermoelectric generator was evaluated, and the test 
results are discussed and analyzed in this article. The generator, 
SN-31, utilizes conventional lead teUuride for the N-leg and a 
new improved material for the P-Ieg known as "TAGS." The 
results of tests to estabHsh the electrical characteristic of the 
generator, as well as its ac impedance and thermal dynamic 
behavior, are presented. The degradation characteristic of the 
generator is shown, and a comparison is made with similar gen- 
erators. 

STAR KEY, D. J. 

542 TOPS High-Gain Antenna 

D. J. Starkey 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 157-159, 
December 31, 1970 

This article summarizes the design and development of the 
Thermoelectric Outer-Planet Spacecraft (TOPS) high-gain an- 
tenna. The main reflector for the TOPS high-gain antenna is 
4.25 m in diameter, is unfurlable, and must have a surface 
accuracy of approximately 1 mm rms in order to meet X-band 
efiiciency requirements. The concept embodies hinged radial 
ribs and a compHant mesh reflective surface. A mockup has been 
constructed and an engineering model is being developed. 



254 



STEINBACHER, R. H. 

543 Surveyor Final Reports— Introduction 

L. D. Jaffe and R. H. Steinbacher 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 145-155, 
March 1970 

For abstract, see Jaffe, L. D. 

544 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Ja£Ee, L. D. 



STELZRIED, C. T. 

845 The Quasi-Stationary Coronal Magnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

C. T. Steizried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), and 
J. M. Wilcox (University of California, Berkeley) 

Sol. Phys., Vol. 14, No. 2, pp. 440-456, October 1970 

Pioneer VI was launched into a circumsolar orbit on December 16, 
1965, and was occulted by the sun in the latter half of November 
1968. During the occultation period, the 2292-MHz S-band tele- 
metry carrier underwent Faraday rotation due to the interaction 
of this signal with the plasma and magnetic field in the solar 
corona. The NASA/JPL 210-ft-diameter antenna of the Deep 
Space Network near Barstow, California, was used for the meas- 
urement. The antenna feed was modified for automatic polariza- 
tion tracking for this experiment. 

The measurement results are interpreted with a theoretical 
model of the solar corona. This model consists of a modified 



255 



AUen-Baumbach electron density and a coronal magnetic field 
calculated from both Mount Wilson magnetograph observations 
using a source-surface model and field extrapolations from the 
Explorer 33 satellite magnetometer. The observations and the 
calculated rotation show general agreement with respect to 
magnitude, sense, and timing, suggesting that the use of the 
source-surface model and field extrapolations from 1 AU is a 
valid technique to obtain the magnetic field in the corona from 
4 to 12 solar radii. Variations present can easily be ascribed to 
density enhancements known to be present in the corona. 
Longitudinal variations of the density in the corona cannot be 
obtained from coronagraph observations; thus, a purely radial 
variation was assumed. An improved fit to the Faraday rotation 
data is obtained with an equatorial electron density 

, ,^ /6000 0.002\ , „ ,, 

N^w(-^ + ^j, 4<R<12 

where JR is in solar radii and IV is in cm"'. 



STIMPSON, L D. 

S46 Revised Lunar Surface Thermal Characteristics Obtained 
From the Surveyor V Spacecraft 

L. D. Stimpson and J. W. Lucas 

J. Spacecraft Rockets, VoL 7, No. 11, pp. 1317-1322, 
November 1970 

Higher lunar surface temperatures have been obtained from 
Surveyor data than from Earth-based telescope measurements. 
In addition, temperatures derived from different sensors located 
on the Surveyor spacecraft were not entirely compatible. This 
paper presents the results of error analyses on the Surveyor V 
thermal data. In the compartments, heat conducted from the 
other faces is significant and is included in the latest calculations. 
Derived postsunset temperatures from solar panel data have 
total errors similar to those from the compartment thermal-sensor 
data. The actual temperature-sensor measurement inaccuracies, 
uncertainties in view factors, and conduction effects are the most 
significant sources of error. Other sources are imcertainties in 
internal heat loss, solar absorptance, and emissivity. Error bands 
for these factors are described. The overlapping of these error 
bands with each other and with the Earth-based results illustrates 
the degree of agreement of the data from the different sources. 
For postsunset. Surveyor V data previously had inferred a thermal 
parameter (y), of about 400, whereas Earth-based measure- 
ments indicated y ~ 850. The latest compartment-based y from 
Surveyor V is near 600, and from solar panel data it is near 1000. 



256 



STINNETT, W.G. 

S47 DSN Command System Analysis Group 

W. G. Stinnett 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 146-150, November 30, 1970 

This article describes the functions of the Deep Space Network 
(DSN) Command System Analysis Group. Included are discus- 
sions on real-time functions of the group for support of DSN 
Command System operations and non-real-time analysis tasks. 
The key operational characteristics of the 1971 era DSN Com- 
mand System are also given. 



STIRN, R. J. 

548 Structural Damage in Lithium-Doped Silicon Solar Cells 
Produced by Neutron Irradiation 

R.J. Stirn 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 111-115, 
October 31, 1970 

An investigation was imdertaken to determine the size distribu- 
tion, morphology, and structural characteristics of regions of 
lattice disorder which are produced by irradiating undoped and 
lithium-doped silicon solar cells with neutrons. The research was 
carried out entirely on the electron microscope using the tech- 
niques of surface replication, electron transmission, and electron 
diffraction. Evidence for the presence of precipitated metallic 
lithium was found in all samples. Crater defects thought to be 
associated with the space charge region around vacancy clusters 
were observed in all irradiated samples. The crater defect density 
was found to increase and the defect size was found to decrease 
with increasing irradiation dose and increasing lithium content. 
The crater defects were found to be stable at temperatures be- 
tween 300 and 900°K. Significant annealing was only found in 
the undoped samples which were irradiated at the lowest doses. 

549 Investigation of Radiation Damage in Lithium-Diffused 
Silicon Solar Cells by Infrared Techniques 

R. J. Stirn 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 115-117, 
October 31, 1970 



257 



Research was undertaken to study the nature of electron 
radiation-induced defects in Hthium-diffused silicon and their 
annealing characteristics using infrared photoconductivity and 
infrared absorption measurements. The background photocon- 
ductivity on unirradiated samples was 50 to 100 times smaller 
than for irradiated samples and no well-defined energy levels 
were detected. Levels in irradiated lithium-doped samples were 
observed at 0.28, 0.39, 0.64, and 0.82 eV from a band edge in 
oxygen-rich siHcon, and at 0.34, 0.65, and 0.86 eV in oxygen-lean 
silicon. In addition, both types gave indication of strong con- 
tribution to the photoconductivity from a level (levels) less than 
0.20 eV from a band edge. No levels corresponding to the 
divacancy or phosphorous-vacancy were detected. Annealing 
experiments showed that all levels anneal out by 450°C. In 
oxygen-lean silicon, a new level appears above 300° C at 0.92 eV. 
Identification of any of these levels with known defects, and 
correlation of the results with known degradation properties of 
irradiated silicon solar cells could not be made. An infrared 
absorption band was observed at 9.90 /* at 80°K in oxygen-rich 
silicon and is attributed to the (OLi)+ complex. At irradiation 
doses of greater than about 10^' electrons/cm^, the 9.9-fi band 
anneals out at 130°C and a new band at 13 /i appears, which in 
turn anneals at 200° C. 



STIVER, R. A. 

550 Mark IIIA IBM 360/75 Computer Configuration 

R. A. Stiver 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 71-75, November 30, 1970 

Organizational aspects of the Mark IIIA IBM 360/75 computer 
configuration, including details of the memory and auxiliary 
storage, computation, and real-time input/output interface sub- 
systems, are presented. The reference block diagram indicates 
interconnection between the subject subsystems and an overview 
of the related subsystems. 

STRAND, L. D. 

551 Low-Pressure L* -Combustion Limits 

L. D. Strand 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 179-180, 

December 31, 1970 



258 



Data was obtained on the ejBEt^. ui several propellant variables 
on the low-pressure/L='=-extinction limit. These variables included 
propellant binder, oxidizer coarseness, and the addition of oxa- 
mide, a coolant additive. The results did not support any simple 
correlation between the ease of extinguishment and propellant 
burning rate. Other complicating factors included the nature of 
the binder decomposition, transparency of the propellant to 
thermal radiation, and the mechanisms of burning rate catalysts 
and depressants. 



STURMS, F. M., JR. 

S52 Polynomial Expressions for Planetary Equators and Orbit 

Elements With Respect to the Mean 1950.0 Coordinate System 

F. M. Sturms, Jr. 

Technical Report 32-1508, January 15, 1971 

Expressions are presented for the mean orbital elements of the 
nine planets with respect to the mean equinox and ecliptic of 
1950.0. Also, expressions are presented for the right ascension 
and declination of the north pole of each of the nine planets 
with respect to the mean equinox and earth equator of 1950.0. 
The expressions are polynomials in time T measured in Julian 
centuries from the epoch January 1.0, 1950 E.T. The expressions 
are useful for coordinate transformations and approximate plan- 
etary ephemerides in astrodynamic computer programs. 



SUTTON, G. H. 

S53 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffa, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. iVi. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 

Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 155-160, 
March 1970 

For abstract, see Jaffe, L. D. 

259 



SYDNOR, R. L. 

S54 Group Delay Measurements of Block IIIC Receiver-Exciter 

Modules 

R. L. Sydnor and G. Thompson 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 27-28, November 30, 1970 

To attain the ranging accuracy required by the Mark III Data 
System Development Plan, the Deep Space Instrumentation 
Facility receiver-exciter system must have a total group-delay 
stability of better than 10 ns. There is no verification that the 
present Block IIIC system meets this requirement. A measure- 
ment program has been started to determine the group-delay 
stability of the components of the receiver-exciter system. The 
measurement technique is described and test results are given 
for several system modules. A preliminary conclusion is that 
some components are much more critical than others with 
respect to group delay. Further measurement plans are outlined. 



SZEJN, R. 

S55 Optimization and Reliability Calculations for Multi-Thermionic- 
Converter Systems 

R. Szejn and K. Shimada 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 76-80, 

December 31, 1970 

To realize an electric power system that is flyable for an extended 
space mission, the system reliability must be predicted and must 
be optimized to be compatible with mission length. Such a 
system is likely to have a large number of individual power 
generating devices that are connected in matrix configuration 
to meet the required power output and the redundancy neces- 
sary for a highly reliable system. In this article, approaches to 
optimization and reliability calculations for such power systems 
are presented along with an analysis of a sample system. The 
system is a three dimensional matrix of thermionic energy con- 
verters which are approximated by linear elements. The calcula- 
tions are based on a linear systems analysis, combined with 
either a straightforward probability technique or a Monte Carlo 
technique. The latter method is successfully applied in optimiz- 
ing the design of a 150-W thermionic generator system. This 
method is also applicable to practically all power systems, pro- 
vided that they can be approximated by a linear model. 



260 



TAHERZADEH, M. 

TOl Neutron Yield From (a, n) Reaction With O^s Isotope 

M. Taherzadeh and M. A. Dore 

Supporting Research and Advanced Developnnent, 
Space Programs Summary 37-65, Vol. Ill, pp. 58-64, 
October 31, 1970 

The neutron yield from the (a,n) reaction with oxygen is evalu- 
ated by integrating the reaction rate equation over all a-particle 
energies and all center of mass angles. The results indicate that 
for a PuOa fuel power source one should expect a total neutron 
yield of (1.05 ±0.24) X 10* neutrons per gram of PuOj per second 
from the (a,n) reaction with oxygen. This result is compatible 
with the experimental value obtained for the same nuclear 
reaction. 

TALBOT, T. D. 

T02 DSN Progress Report for November-December 1970: 

Choice of Integrators for Use With a Variation-of-Parameters 
Formulation 

T. D. Talbot and E. A. Rinderle 

Technical Report 32-1526, Vol. 1, pp. 117-121, 
February 15, 1971 

In searching for better methods of computing the orbit of a 
satellite over many revolutions, a special perturbations theory 
using a variation-of-parameters formulation has been developed. 
As a prelude to obtaining vaHd comparisons with the Cowell 
technique currently in use, a study of various integrators was 
made in an effort to find the integrator best suited to a variation- 
of-parameters formulation. This study was initiated in response 
to suggestions that, for a given set of differential equations, there 
exists an optimum integrator. Three integrators were compared 
by the execution of two sets of test cases. The integrators were 
first compared in the predict-only mode and then in the predict- 
correct mode. The numerical results of these studies and the 
conclusions reached are presented in this article. 

TAPPAN, R. W. 

T03 Tau Ranging Subsystem Rebuild 

R. W. Tappan 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 138-140, November 30, 1970 



261 



The tau planetary ranging equipment originally installed at 
DSS 14 (Mars Deep Space Station) has been redesigned and 
rebuilt to improve its operational and performance character- 
istics. This article discusses the significant improvements that 
have been incorporated into the equipment. The tau ranging 
subsystem has been functionally tested and re-installed at DSS 14 
for use with the Mariner Mars 1971 mission. 



TAOSWORTHE, R. C. 

T04 DSN Progress Report for November-December 1970: 

A Second/Third-Order Hybrid Phase-Locked Receiver for 

Tracking Doppler Rates 

R. C. Tausworthe 

Technica! Report 32-1526, Vol. I, pp. 42-45, February 15, 1971 

This article describes a stable phase-locked receiver configuration 
for tracking frequency ramp signals. A usual second-order 
receiver is used for lockup; subsequently, a very simple modifi- 
cation is made to the loop filter, alteriag the loop to one of the 
third order. The altered loop then tracks the incoming signal with 
zero static phase error. The receiver bandwidth is practically 
unchanged; the damping factor hes in the region 0.5 and 0.707, 
and the design point is 12 dB in gain margin above instability. 

T05 An Asymptotic Formula for the Mean Cycle-Slip Time of 
Second-Order Phase-Locked Loop With Frequency Offset 

R. C. Tausworthe 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 42-48, November 30, 1970 

Previous work has shown the mean time from lock to a slipped 
cycle of a second-order phase-locked loop is given by a certain 
double integral. Accurate numerical evaluation of this formula 
has proven extremely vexing because the difference between ex- 
ponentially large quantities is involved. This article simphfies the 
formula to avert this problem, and then produces an asymptotic 
formula for the mean slip time that is surprisingly accurate even 
at low loop signal-to-noise ratios and moderate frequency offsets. 



THOMPSON, G. 

106 Group Delay Measurements of Block IIIC Receiver-Exciter 

Modules 

R. L. Sydnor and G. Thompson 

262 



The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 27-28, November 30, 1970 

For abstract, see Sydnor, R. L. 



THULEEN, K. L 

T07 Tracking System Analytic Calibration Activities 
for the Manner Wlars 1969 Wlission 

B. D. Mulhall, C. C. Chao, N. A. Mottinger, P. M. Muller, 
V. J. Ondrasik, W. L. Sjogren, K. L Thuieen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 

For abstract, see Mulhall, B. D. 

TIMOR, U. 

T08 Space Station Unified Communication: Efficiency of Biphase- 
Modulated Subcarriers, N-Channe! Telemetry Systems 

U. Timor 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 27-30, 
October 31, 1970 

The Manned Space Station high-rate links will have a multi- 
plicity of channels. The efficiency of such N-channel digital co- 
herent systems, where the data signals phase modulate the carrier 
with biphase-modulated subcarriers, is investigated. Two types 
of modulation are considered: linear binary phase-shift keying 
(BPSK) and interplex BPSK. For small N {N < 4), the interplex 
configuration is always superior. On the other hand the efficiency 
of the linear system is never below 36.8% = e'^ no matter how 
large N is. However, for large N, the system to use is a con- 
catenation of the two-channel interplex systems, which can be 
shown to be as efficient (theoretically 100%) as time-multiplex. 
Complete results, which show the efficiency of both systems for 
different power distributions in the N channels, are presented. 

T09 Space Station Unified Communication: Equivalence of Time- 
Multiplex and PSK Signals for Digital Communication 

U. Timor 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 36-39, 
October 31, 1970 

In comparing different techniques for multiplexing N binary data 
signals into a single channel such as would exist on the Manned 



263 



Space Station, time-division multiplexing is known to have a 
theoretical efficiency of 100% (neglecting sync power), and thus 
seems to outperform frequency -multiplexed subcarrier systems. 
In this article, it is shown that, using four-phase shift keying 
(PSK) of a squarewave subcarrier, an efficiency of 100% can be 
achieved. Thus, this scheme of PSK modulation is shown to be 
as efficient as time-division multiplexing. Therefore, the two 
seemingly different modulation schemes are, in effect, completely 
equivalent. 

TIO Optimum Configurations for PSK/PM Systems 

U. Timor 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-66, Vol. Ill, pp. 33-36, 

December 31, 1970 

The performance of IV-channel phase-shift-keyed/phase- 
modulated (PSK/PM) digital communication systems is investi- 
gated. It is shown that for aU possible power allocations to the 
data and RF channels either the Interplex scheme or the 
conventional modulation scheme is optimum (not necessarily 
unique). Therefore, to find the best performance achievable by 
PSK/PM systems, the investigation can be narrowed to these 
two schemes. Thus, a wide variety of multichannel multiplex 
schemes need not be developed. 



TOM, H. Y. 

Tl 1 Investigation of Sterilizable Battery Separators 

[August-September 1970] 

E. F. Cuddihy, D. E. Walmsley, J. Moacanin, and H. Y. Tom 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. ill, pp. 171-176, 
October 31, 1970 

For abstract, see Cuddihy, E. F. 



TOTH, L. R. 

T12 Component Storage With Propellants 

W. F. MacGlashan and L. R. Toth 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, p. 179, 
October 31, 1970 

For abstract, see MacGlashan, W. F. 



264 



T13 Material Compatibility [August-September 1970] 

0. F. Keller and L R. Toth 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 180-181, 
October 31, 1970 

For abstract, see Keller, O. F. 

TRASK, D. W. 

T14 Tracking System Analytic Calibration Activities 
for the Mariner Mars 1969 Mission 

B. D. Mulhall, C. C. Chao, N. A. Mottinger, P. M. Muller, 

V. J. Ondrasik, W. L. Sjogren, K. L. Thuleen, and D. W. Trask 

Technical Report 32-1499, November 15, 1970 

For abstract, see Mulhall, B. D. 

T15 DSN Progress Report for November-December 1970: 
DSN Inherent Accuracy Project 

T. W. Hamilton and D. W. Trask 

Technical Report 32-1526, Vol. I, pp. 11-13, February 15, 1971 

For abstract, see Hamilton, T. W. 

TRUSCELLO, V. 

T16 Thermoelectric Generators for Deep Space Application 

P. Rouklove and V. Truscello 

Technical Report 32-1495, January 15, 1971 

For abstract, see Rouklove, P. 

TURKEVICH, A. L 

T17 Surveyor Final Report— Principal Scientific Results From 
the Surveyor Program 

L. D. Jaffe, C. 0. Alley (University of Maryland), 
S. A. Batterson (Langley Research Center), E. M. Christensen, 
S. E. Dwornik (NASA Headquarters), D. E. Gault (Ames 
Research Center), J. W. Lucas, D. 0. Muhleman (California 
Institute of Technology), R. H. Norton, R. F. Scott (California 
Institute of Technology), E. M. Shoemaker (U.S. Geological 
Survey), R. H. Steinbacher, G. H. Sutton (University of Hawaii), 
and A. L. Turkevich (University of Chicago) 



265 



Icarus: Int. J. Sol. Sys., Vol. 12, No. 2, pp. 156-160, 
March 1970 

For abstract, see Jaffa, L. D. 



VOLKOFF, J. J. 

¥01 Discernibility of CRT Gray Shades 

J. J. Volkoff 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 97-98, November 30, 1970 

An experiment was performed to determine the luminances at 
wMch shades of gray produced on a cathode-ray tube (CRT) moni- 
tor are discerned. The experiment is described and the results 
are presented in terms of luminance difference required between 
gray shades as a function of luminance of the brighter shade. 

WADA, B. K. 

WOl Equivalent Spring-Mass System for Normal Modes 
R. M. Bamford, B. K. Wada, and W. H. Gayman 
Technical Memorandum 33-380, February 15, 1971 
For abstract, see Bamford, R. M. 

WAHLQUiST, H. D. 

W02 Solution of Partial Differential Systems 

F. B. Estabrook, B. K. Harrison (Brigham Young University), 
and H. D. Wahlquist 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. ill, p. 17, 

December 31, 1970 



For abstract, see Estabrook, F. B. 



WALMSLEY, D. E. 

W03 investigation of Sterilizable Battery Separators 

[August-September 1970] 

E. F. Cuddihy, D. E. Walmsley, J. Moacanin, and H. Y. Tom 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 171-176, 
October 31, 1970 

For abstract, see Cuddihy, E. F. 



266 



WELLER, R. E. 

W04 Block IV Receiver-Exciter Development 

H. Donnelly, A. C. Shallbetter, and R. E. Waller 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 115-124, November 30, 1970 

For abstract, see Donnelly, H. 



WELLS, R. A. 

W05 DSN Progress Report for November-December 1970: 

Diagnostics for the Mark IIIA Central Processing System: 
IBM 360/75 Computer On-line Test Routines 

R. A. Wells 

Technical Report 32-1526, Vol. I, pp. 103-106, 
February 15, 1971 

Described in this article is a family of real-time on-line diag- 
nostics that was developed to check out all IBM-360/75-related 
components of the Space Flight Operations Facility Mark IIIA 
central processing system. Diagnostic requests are entered from 
a cathode-ray-tube display station, initiating concurrent tests of 
assorted user devices and communications links. A supervisory 
software monitor program coordinates execution and, where 
necessary, draws on the facihties of the JPL operating system in 
each IBM 360/75 computer. 



WEN, L 

W06 Thermal Radiative Characteristics of Solar Arrays 
Determined by Calorimetric Techniques 

LWen 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 137-141, 
October 31, 1970 

EfiFective solar absorptances and total hemispherical emittances 
of various types of solar cell modules were determined with 
calorimetric techniques. Sample specimens include five different 
modules, three painted surfaces, and two Mariner corrugated 
substrates. Emittances were measured at five temperature levels 
between -75 and 150° C. 



267 



WENGERT, R. 

W07 High-Speed Data/Wide-Band Data Input/Output Assembly 

R. Wengert, L. DeGennaro, and J. Mclnnis 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. li, pp. 133-136, November 30, 1970 

The high-speed data/wide-band data (HSDAVBD) input/output 
assembly provides the interface and logic required for the bidi- 
rectional transfer of high-speed (4.8 kbits/s) and wide-band 
(50 kbits/s) information between the telemetry and command 
processor (TCP) computer and the HSD/WBD equipment in the 
Ground Communications Facility equipment. The former TCP 
high-speed data equipment provided a 2.4-kbit/s unbuffered 
send-only capability. Detailed functional descriptions of the 
modes of operations for the HSD/WBD input/output assembly 
are discussed in this article. The status of implementation at 
Deep Space Instrumentation Facility stations is also included. 

WHITE, A. B. 

W08 Optimal Methods for Computing the Incomplete 
Gamma and Related Functions 

A. B. White 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 3-11, 
October 31, 1970 

Three methods of computing the incomplete gamma function 
are investigated: a zero-value marching algorithm, a power series 
technique, and a continued fraction method. The focus of each 
discussion is the development of techniques for computing se- 
quences of the incomplete gamma function correct to any desired 
absolute accuracy. Miscellaneous properties of the incomplete 
gamma are also discussed. 



WHITE, N. 

W09 The Critical Problem and Coding Theory 

N. White 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 36-42, 
December 31, 1970 

This article investigates in detail the interesting fact that the 
critical problem of combinatorial geometry contains, as a special 



268 



case, the problem of determining the largest dimension possible 
for a linear code over GF{q), the finite field of order q, of fixed 
length and minimum distance. Following an introduction to the 
critical problem and its relationship to coding theory, the critical 
problem for B"^, q = 2; the critical problem for Bj, w>S,q = 2; 
recursion for p(A; B"), and values for p are discussed. 

WICK, M. R. 

WIO Programmed Oscillator Development 

M. R. Wick 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. II, pp. 127-132, November 30, 1970 

Programmed oscillators have been under development over the 
past several years for use in deep space commxmications, radar 
astronomy, and most recently in the time-synchronization trans- 
mitter of the Deep Space Network (DSN). This article describes 
one phase of the development activity of programmed oscillators 
for possible application in the DSN. The particular technique 
described utilizes a Dana digiphase synthesizer that is remotely 
and digitally controlled. A brief description of the digital control 
is also given. 

WILCOX, J. M. 

Wll The Quasi-Stationary Coronal Magnetic Field and Electron 
Density as Determined From a Faraday Rotation Experiment 

0. T. Stelzried, G. S. Levy, T. Sato, W. V. T. Rusch (University 
of Southern California), J. E. Ohison (University of Southern 
California), K. H. Schatten (Goddard Space Flight Center), 
and J. M. Wilcox (University of California, Berkeley) 

Sof. Phys., Vol. 14, No. 2, pp. 440-456, October 1970 

For abstract, see Stelzried, C. T. 

WILLEMS, A. IVI. 

W12 Simulation Center Hardware Development— Programmed 
Input/Output Serial Data Generators and Receivers 

A. M. Willems 

The Deep Space Network, Space Programs Summary 37-66, 
Vol. 11, pp. 70-71, November 30, 1970 

The EMR 6050 computer in the Simulation Center receives from 
and outputs to the Ground Communications Facility serial data 



259 



streams. These data streams comprise simulated tracking, telem- 
etry, command, monitor, and operations control data in formats 
identical to mission data. The EMR 6050 processes these data in 
parallel format, thus requiring conversions to and from serial 
format. The programmed input/output serial data generators 
and receivers that perform this function are described in 
this article. 



WILLIAMS, H. E. 

W13 Boundary Layer Equations of a Heated Constrained 

Spherical Shell 

H. E. Williams (Harvey IVIudd College) 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 136-140, 

December 31, 1970 

The general equations governing the nonlinear, thermoelastic 
behavior of thin shells of revolution are simplified by an order 
of magnitude analysis to study boimdary layer development in 
spherical shells. The range of thermal strain studied produces 
transverse deflections comparable with the shell thickness. The 
boundary layer equations are developed first for a general asym- 
metric temperature rise (constant through the shell thickness) 
and then applied to the case of a uniformly heated, shallow 
spherical shell. The resulting equations are hnear in the stress- 
displacement variables. However, as the in-plane displacements 
are nonlinearly related to the slope of the transverse displace- 
ment, the temperature dependance of the in-plane displacements 
is nonlinear. Finally, it is shown that the equations derived for 
shallow, spherical shells also apply to ellipsoidal shells of 
revolution. 

W14 Deri¥ation of the Equations Governing Heated Shallow Shells 

of Revolution 

H. E. Williams (Harvey IVIudd College) 

Supporting Researcli and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 141-144, 

December 31, 1970 

The general equations derived earlier by the author are shown 
to contain Marguerres equations when simplified by an order of 
magnitude analysis. The range of thermal strain studied is com- 
parable to that sufficient to cause buckling of a flat, circular plate 
of the same thickness and span. It is assumed further that a 
boundary layer does not develop and stress-displacement vari- 



270 



ables vary significantly over lengths comparable with the span 
of the shell. Although the development is applied to a spherical 
shell, it can be shown that the equations also apply to shallow, 
ellipsoidal shells of revolution. 



WILLIAMSON, R. E. 

W15 Automated Test Techniques for Guidance and Control 
Subsystems 

R. E. Williamson 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 90-91, 
December 31, 1970 

The complexity of the long-life outer-planet spacecraft is such 
that automated testing will be required. This article describes 
the development of guidance and control automated support 
equipment technology which is in process to meet the require- 
ments of future planetary missions. 



WINKELSTEIN, R. 

W16 DSN Progress Report for November-December 1970: 
Digital Modulator 

R. Winkelstein 

Technical Report 32-1526, Vol. I, pp. 63-65, February 15, 1971 

Utilization of the increased capability of the Mars Deep Space 
Station (DSS 14) transmitter and antenna for planetary radar 
transmission has been made possible by the design, construction, 
and installation of a digital modulator at DSS 14. As described 
in this article, this device reshapes the digital modulating wave- 
form generated at the Venus Deep Space Station (DSS 13) and 
received over the microwave link at DSS 14. The digital modu- 
lator output is an accurately adjustable 2-level waveform used 
to biphase-modulate the transmitter frequency. During pre- 
calibration setup, the digital modulator provides selectable 
frequency square waves used in correctly adjusting the waveform 
amplitude to obtain carrier suppression greater than 40 dB. The 
capability that this technique provides has been demonstrated 
in planetary radar experiments. By this method, one station's 
processor can be used to generate commands to be sent to a 
spacecraft from another station at the same complex, thus 
increasing the reliability of the Deep Space Network (DSN) 
command system. 



271 



WINN, F. B. 

W17 DSN Progress Report for November-December 1970: 
Refractivity Influence on DSS Doppler Data 

F. B. Winn and R. K. Leavitt 

Technical Report 32-1526, Vol. I, pp. 31-41, February 15, 1971 

As described in this article, doppler data from deep space 
missions show terrestrial media contamination influences even 
after least-square fitting. Cross-correlation between solution 
parameters and the media-induced errors is large enough to 
adversely affect parameter least-square adjustments. When a scale 
factor for Cain's tropospheric refractivity profile is included in 
the parameter list, the media-induced observed-minus-computed 
(O — C) structures do not appear above 15-deg elevation. When 
the scale factor is not included, O — C structures commence to 
appear at '~-25-deg elevation. 



WONG, S. K. 

W18 The Mariner VI and Vll Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendail, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 

For abstract, see Gordon, H. J. 



WOO, K. 

W19 Spacecraft Antenna Research: Further RF Study of Reflector 
Surface Materials for Spacecraft Antennas 

K. WooandT. Y. Otoshi 

Supporting Research and Advanced Deve/opment, 
Space Programs Summary 37-65, Vol. Ill, pp. 47-52, 
October 31, 1970 

A computerized network analyzer technique permitting rapid 
measurement of RF loss and phase characteristics of reflector 
surface materials for spacecraft antennas is described. The RF 
reflectivity losses at 8448 MHz of gold-plated Chromel-R mesh. 



272 



Paliney-7 mesh, silver-plated nylon mesh, perforated stainless 
steel sheet, perforated aluminum sheet, and perforated copper- 
clad glass epoxy laminate measured by the network analyzer 
method are presented. 

W20 Spacecraft Antenna Research: S/X-Band High-Gain Antenna 
Feed for Thermoelectric Outer-Planet Spacecraft 

K.Woo 

Supporting Research and Advanced Development, 
Space Programs Summary 37-65, Vol. Ill, pp. 52-57, 
October 31, 1970 

A high-gain antenna feed has been developed for the Thermo- 
electric Outer-Planet Spacecraft. The feed is designed to operate 
with linearly polarized signals and is capable of: (1) transmitting 
telemetry at both 8448 and 2295 MHz, (2) receiving commands 
at 2115 MHz, and (3) angle-tracking at 2115 MHz. Test results 
show that the feed provides high efficiency at all operating fre- 
quencies and good monopulse tracking capability. 



YANG, J.-N. 

YOl Optimum Pressure Vessel Design Based on Fracture 
Mechanics and Reliability Criteria 

E. Hear and J.-N. Yang 

Technical Memorandum 33-470, February 1, 1970 

For abstract, see Heer, E. 

Y02 Optimization of Space Antenna Structures 

E. Heer and J.-N. Yang 

Technical Memorandum 33-472, March 15, 1971 

For abstract, see Heer, E. 

YOB Creep Failure of Randomly Excited Structures 

J.-N. Yang 

Supporting Researct^ and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 120-128, 
December 31, 1970 

A method is developed for the prediction of creep failure of 
structures under random excitations. The fracture mechanics 



273 



concept and the cumulative flaw growth hypothesis have been 
employed to obtain the statistical characteristics of the relative 
flaw growth of structures under random loadings. The probability 
of creep failure is evaluated using the principle of maximum 
entropy. Two numerical examples are used to illustrate the 
general results. 

Y04 Reliability of Randomly Excited Structures 

J.-N. Yang and E. Hear 

Supporting Research and Advanced Development, 
Space Progranns Summary 37-66, Vol. Ill, pp. 128-136, 

December 31, 1970 

A method is developed to predict the reliability of structures 
under stationary random excitations. The present approach takes 
into account the interaction of catastrophic failure modes and 
fatigue failure modes as well as the statistical variation of the 
material strength. Fracture mechanics and extreme point pro- 
cesses are employed throughout the formulation. It is demon- 
strated that neglecting the interactions of failure modes, or 
disregarding the statistical dispersion of the material strength, 
results in an unconservative reliability estimate. 



YASUI, R. K. 

Y05 Effects of High-Temperature, High-Humidity Environment on 

Silicon Solar Cell Contacts 

R. K. Yasui and P. A. Barman 

Technical Report 32-1520, February 15, 1971 

The electrical and mechanical characteristics of various solar cell 
contact systems after exposure to a high-temperature, high- 
humidity environment were investigated at the Jet Propulsion 
Laboratory. The results are discussed. An unexpected failure 
mode involved degradation of the sihcon monoxide antireflective 
coating after environmental exposure. Significant degradation of 
electrical characteristics was observed in cells having palladium- 
containing Ti-Ag contacts, and differences in contact structure 
and composition were noted between different manufacturers. 
Non-palladium-containing Ti-Ag contacts on lithium-doped cells 
showed a surprising degree of stability. In general, the most 
stable contact system, electrically and mechanically, was the 
solder-coated, Ti-Ag system used on the Mariner Mars 1969 
solar cells. 



274 



YEATES, C. M. 

Y06 Experimental Study of Magnetic Flux Transfer at 
tfie Hyperbolic Neutral Point 

A. Bratenahl and C. M. Yeates 

Phys. Fluids, Vol. 13, No. 11, pp. 2696-2709, November 1970 

For abstract, see Bratenahl, A. 

YEN, S. P. S. 

Y07 Energy Transfer in Bipyridilium (Paraquat) Salts 

A. Rembaum, V. Hadek, and 8. P. S. Yen 

Supporting Researcli and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 189-191, 
December 31, 1970 

For abstract, see Rembaum, A. 

YOUNG, A. T. 

Y08 Saturation of Scintillation 

A. T. Young 

J. Opt. Soc. Am., Vol. 50, No. 11, pp. 1495-1500, 
November 1970 

Recent observations o£ stellar scintillation provide new evidence 
that atmospheric dispersion alone is not sufficient to cause the 
saturation observed at large zenith angles. Saturation is produced 
by lateral spreading of the (initially coUimated) light in travers- 
ing the turbulent atmosphere — a phenomenon called seeing by 
astronomers, or multiple scattering by optical physicists. The 
magnitude of this effect, as estimated from stellar scintillation 
data, agrees well with the minimum resolution predicted by Fried 
and by Hulett and is correlated as expected with the strength of 
scintillation in the zenith. The observational data, the theory, 
comparisons of observation and theory and with earlier results, 
and saturation in other scintillation data are discussed. 

Y09 Improved Constants for the 7820 A and 7883 A Bands of CO2 

L. D. G. Young, A. T. Young, and R. A. Schorn 

J. Quant Spectrosc. Radiat. Transfer, Vol. 10, No. 12, 
pp. 1291-1300, December 1970 

For abstract, see Young, L. D. G. 



275 



YIO Improved Solar Wavelengths Between 7780 and 7925 A 
A. T. Young and R. A. Schorn 
Sol. Phys., Vol. 15, No. 1, pp. 97-101, November 1970 

By utilizing the known rotational constants for the 7820 and 
7883 A CO2 bands, the authors were able to derive substantially 
improved wavelengths for solar lines in the 7780-7925 A region. 
It seems unlikely that any of the values obtained (with the excep- 
tions that are noted) is in error by as much as 0.010 A, and the 
results are believed to represent a substantial improvement over 
the catalog values for many of the lines. 

YOUNG, L D. G. 

Yll High-Dispersion Spectroscopic Observations of Venus: IX. The 
Carbon Dioxide Bands at 12,030 and 12,177 A 

L. D. G. Young, R. A. J. Schorn, and H. J. Smith (University 
of Texas) 

Icarus: Int. J. Sol. Sys., Vol. 13, No. 1, pp. 74-81, July 1970 

Observations ofthe 12,030- and 12,177-A bands of carbon dioxide 
in the spectrum of Venus were made from March through May 
1967. The 10 best spectra were used to derive rotational tem- 
peratures. Two methods were used. A linear-least-squares fit to 
a square-root absorption law yielded an average rotational tem- 
perature of 238 ±5 °K, while a curve-of-growth technique gave 
an average rotational temperature of 236 ±5 °K. The rotational 
temperatures showed no significant variation with the phase 
angle, i, of Venus for our restricted range of 49 < i, deg < 63. 

Y12 Interpretation of High-Resolution Spectra of Venus: II. 
The (102-000) II Band of lacisQiso at 1.71 Microns 

L. G. Young 

Icarus; Int. J. Sol. Sys., Vol. 13, No. 2, pp. 270-275, 
September 1970 

High-resolution spectra obtained by Pierre and Janine Connes 
in the region of 1.7 microns have been used to obtain a curve 
of growth for the (102-000)ii band of the «C"0^«0 isotope of 
carbon dioxide. Several methods of data reduction have been 
employed. Assuming a constant rotational line half-width, we 
find a rotational temperature for Venus of Trot = 242° ± 2°K in 
agreement with our previous results. When a variable line half- 
width is used, the rotational temperature is increased to 
249°±3°K. 



276 



Y13 Improved Constants for the 7820 A and 7883 A Bands of CO2 

L. D. G. Young, A. T. Young, and R. A. Schorn 

J. Quant Spectrosc. Radiat. Transfer, Vol. 10, No. 12, 
pp. 1291-1300, December 1970 

High-dispersion spectra of Venus are used in obtaining line posi- 
tions and band constants for the (105)i and (105)ii bands of COo. 
An improved method of analysis is used to obtain very accurate 
results. Assuming B" = 0.390218 and D" = 13.3 X 10-« for the 
groxmd state, the following values are obtained: 



Constant 



Value for 7820-A Value for 7883-A 

band band 



«„, cm-^ 12774.727 ±0.002 12672.274 ±0.004 

B' 0.374540 ±0.000006 0.375657 ±0.000014 

D' 10.9 X 10-^ ±0.4 17.2 X 10-" ±1.7 

The values for <oo and B' are at least an order of magnitude more 
accurate than those given by Herzberg and Herzberg in 1953, 
and the D' values are new. 



YOUNGBERG, C. L 

Y14 Holographic Study of Operating Compact-Arc Lamp 

C. G. Miliar and C. L Youngberg 

Supporting Research and Advanced Development, 
Space Programs Summary 37-66, Vol. Ill, pp. 171-174, 
December 31, 1970 

For abstract, see Miller, C. G. 

ZANDELL, C. 

ZOl DSN Progress Report for November-December 1970: 
IBWI 360/75 Computer Time interface 

C. Zandell 

Technical Report 32-1526, Vol. I, pp. 107-109, 
February 15, 1971 

The IBM 360/75 computer time interface and the capabilities of 
two custom-feature modifications of the IBM 360/75 are de- 
scribed. The modified IBM 360/75 accepts signals from an 
existing time reference, provides GMT with 10-ps resolution, 
includes an interval timer, and provides programmable interrupts. 



277 



Z02 DSN Progress Report for November-December 1970: 
IBM 360/75-Univac 1108 Computer Interface 

C. Zandell 

Technical Report 32-1526, Vol. I, pp. 110-112, 
February 15, 1971 

In the functional design of the Space FHght Operations Facility 
(SFOF) for the 1970-1972 era, a capability for interfacing the 
central processing system with the scientific computing facility 
will exist. This interface is required to implement the transfer 
of orbital and trajectory data between programs in the IBM 
360/75 and the Univac 1108 computers for the Mariner Mars 
1971 and Pioneer F missions. This article describes the interface 
design which provides a method of serial synchronous com- 
munication for short distances without the use of modems. 
Reducing the total resistance between the current mode drivers 
and receivers makes transmission lengths of 400 ft possible. 
External timing replaces the modem function, allowing the direct 
connection of serial synchronous devices. 



ZIELENBACK, J. W. 

Z03 The Mariner V} and VII Flight Paths and Their 
Determination From Tracking Data 

H. J. Gordon, D. W. Curkendall, D. A. O'Handley, 
N. A. Mottinger, P. M. Muller, C. C. Chao, B. D. Mulhall, 
V. J. Ondrasik, S. K. Wong, S. J. Reinbold, J. W. Zielenback, 
J. K. Campbell, R. T. Mitchell, J. E. Ball, W. G. Breckenridge, 
T. C. Duxbury, and R. E. Koch 

Technical Memorandum 33-469, December 1, 1970 
For abstract, see Gordon, H. J. 



ZOHAR, S. 

Z04 DSN Progress Report for November-December 1970: 
Matched Filters for Binary Signals 

S. Zohar 

Technical Report 32-1526, Vol. I, pp. 52-62, 

February 15, 1971 

Matched filters for the optimal high-speed detection of binary 
signals are designed, and their performance as a function of their 
complexity is explored. The range of filters designed extends 



278 



from a 2-element filter whose performance is about 0.7 dB below 
the ideal filter up to a 20-element filter with a degradation of 
about 0.1 dB. 



ZYGIELBAUM, A. I. 

Z05 DSN Progress Report for November-December 1970: 

Probing the Solar Plasma With Mariner Radio Metric Data, 
Preliminary Results 

P. F. MacDoran, P. S. Callahan, and A. 1. Zygielbaum 

Technical Report 32-1526, Vol. I, pp. 14-21, 
February 15, 1971 

For abstract, see MacDoran, P. F. 



279 



Subject Index 



Subject Entry 

Acoustics 
near-field supersonic boom pressure tests in 

JPL 20-in. supersonic wind tunnel M04 

Antennas and Transmission Lines 
polarization diversity S-band cone 

waveguide/polarimeter calibrations B07 

spacecraft antenna tolerances D02 

mesh materials for deployable antennas F03 

development of a conical-gregorian high-gain antenna F04 

Mars Deep Space Station (DSS 14) 210-ft-diam antenna 

hydrostatic bearing runner level reference GOl 

optimization of spacecraft antenna structures H17 

evaluation of reflector surface distortions K04 

antenna rigging angle optimization within 

structural member design optimization L13 

Mars Deep Space Station (DSS 14) 210-ft-diam 

antenna thrust collar survey L24 

high-power feed component development Mil 

polarization diverse S-band feed cone N02 

calibration of RF properties of 210-ft-diam 

antenna mesh Oil 

system operating noise temperature calibrations 

of low noise cones R03 

S-band polar ultra cone improvement R05 

antennas used by Tracking and Data System 

in support of Pioneer VI RIO 

high-gain antenna for Thermoelectric Outer-Planet 

Spacecraft (TOPS) S42 

relector surface materials for spacecraft antennas W19 

S/X-band high-gain antenna feed for Thermoelectric 

Outer-Planet Spacecraft (TOPS) W20 



280 



Subject Entry 

Apollo Project 

changes on lunar surface during 31 months determined 
from comparison of Surveyor III and Apollo 12 
photographs J04 

Atmospheric Entry 
fabrication development of lightweight RF-transparent 
honeycomb-sandwich structures for atmospheric 
entry vehicles NOl 

Biology 

isolation and characterization of coal in 

Antarctic dry-valley soils B09 

evolution and coding: inverting the genetic code BIO 

soil microbial and ecological investigations 

in the Antarctic interior C02 

microbiological analyses of snow and air 

from Antarctic interior L02 

Chemistry 

relative proton affinity of argon and deuterium B18 

superposition of dynamic mechanical properties 

in glassy state of polymers C29 

significance of Surveyor V chemistry experiments to 

theory of lunar interior G09 

electrical properties of TCNQ salts of ionene 

polymers and their model compounds H03 

multi-phase ammonia-water system H14 

science results from Surveyor Project JOS 

reaction geometry of alkaline silver electrode J22 

shock-tube thermochemistry tables for 

high-temperature gases M15 

presence of crystallinity in hydrogenated polybutadienes M24 

viscoelastic behavior of elastomers undergoing 

crosslinking reactions M26 

chemical analysis of lunar surface from Surveyor 

spacecraft data P14 

energy transfer in bipyridilium (paraquat) salts R07 

Computer Applications and Equipment 

appHcation of nonadaptive transversal filters to 

playback of digital tape recorder signals A08 

computer refreshed display B19 

thermal modeling of spacecraft with imperfect models C13 

Deep Space Network Mark III development C24 

video image display assembly DOS 

Space Flight Operations Facility IBM 360/75 

user device switching assemblies HOI 



281 



Subject Entry 

Computer Applications and Equipment (contd) 

Ground Communications Facility wideband digital data 

system terminal configuration H06 

Viking orbiter system programmable formater 

for engineering telemetry J09 

Mariner Mars 1971 mission and test computer system JIO 

Mark IIIA simulation center EMR 6050-Univac 1108 

computer interface L09 

inbound high-speed and wideband data synchronizers P09 

use of m-ary linear feedback shift registers 

with binary devices P12 

Space Flight Operations Facility central processing 

system model development S27 

functional design of Space Flight Operations Facility 

for 1970-1972 era S28 

Mark IIIA IBM 360/75 computer configuration S50 

tau ranging subsystem rebuild T03 

discernibility of cathode-ray tube gray shades VOX 

IBM 360/75 computer on-line test routines W05 

Deep Space Instrumentation Facility high-speed 

data/wide-band data input/output assembly W07 

Deep Space Network programmed oscillators WIO 

simulation center programmed input/output serial 

data generators and receivers W12 

automated test techniques for control and 

guidance subsystems W15 

IBM 360/75 computer time interface ZOl 

IBM 360/75-Univac 1108 computer interface Z02 

Computer Programs 
user's manual for VISCEL, a general-purpose program 

for analysis of linear viscoelastic structures A04 

program for inverting the genetic code BIO 

programs for determination of Mariner VI and VII 

flight paths from tracking data Gil 

algorithm for obtaining roots of polynomials 

having interval coefficients H09 

user's manual for Thermal Analysis System I program H26 

system of programs for interactive trajectory design K06 

landmark navigation program (LNCP) L15 

programs used in tracking system analytical caHbration 

for Mariner Mars 1969 Project M39 

subroutines to compute planet and satellite 

photometric magnitudes POl 

P02 
IBM 360/75 computer on-line test routines W05 



282 



Subject Entry 

Control and Guidance 

stepper motor drive electronics fof solar-electric 

thrust vector control subsystem C28 

attitude-control single-axis simulator for Thermoelectric 

Outer-Planet Spacecraft (TOPS) FOl 

Mariner VI and VII in-flight maneuvers Gil 

attitude-control single-axis simulator true position encoder 

for Thermoelectric Outer-Planet Spacecraft (TOPS) .G12 

single-axis simulator digital gyro system for Thermoelectric 

Outer-Planet Spacecraft (TOPS) H05 

sizing results for Mariner Mars 1971 spacecraft 

attitude-control gas nozzles J13 

Viking orbiter system sun occultation logic and 

sun sensor null detector J14 

proposed laser obstacle detection sensor for a Mars rover K13 

computerized landmark navigator L15 

inertial and gyrocompass/odometer navigators for 

roving vehicle navigation subsystem L16 

finite element modeling for appendage interaction 

with spacecraft attitude control L19 

attitude control of a flexible solar-electric spacecraft M05 

in-flight calibration of television instrument used 

in optical spacecraft navigation O04 

subroutines to compute planet and satellite photometric 

magnitudes for optical sensors used in navigation POl 

P02 

Mariner Mars 1969 navigation, control, and guidance SIX 

approach guidance sensor subsystem 840 

automated test techniques for control and 

guidance subsystems W15 

Earth Atmosphere 
inverse problems in radiative transfer: determination 

of atmospheric parameters C12 

science results from Surveyor Project J03 

sensitivity of tropospheric range and doppler effects 

to shape of refractivity profile M19 

atmospheric factors in tracking system analytical 

calibration for Mariner Mars 1969 Project M39 

refractivity influence on doppler data W17 

saturation of stellar scintillation Y08 

Earth Motion 

polar motion: doppler determination using satellites 

compared to optical results C17 

polynomial expressions for earth motion S52 



283 



Subject Entry 

Earth Surface 
isolation and characterization of coal in 

Antarctic dry-valley soils B09 

soil microbial and ecological investigations in 

the Antarctic interior C02 

microbiological analyses of snow and air from 

Antarctic interior L02 

Electricity and Magnetism 

experimental study of magnetic flux transfer at 

hyperbolic neutral point B20 

heat transfer from partially ionized argon flowing 

in conducting channel with applied transverse 

magnetic field R14 

terminated capacitor discharge firing of 

electroexplosive devices R15 

theoretical considerations of prebreakdown characteristics 

in a cesium thermionic discharge S14 

Electronic Components and Circuits 

application of nonadaptive transversal filters to 

playback of digital tape recorder signals A08 

superconducting magnet for X-band maser B14 

post-detection recorder evaluation B23 

Deep Space Network Mark III development C24 

stepper motor drive electronics for solar-electric 

thrust vector control subsystem C28 

Deep Space Network Block IV receiver-exciter 

development D06 

Ground Communications Facility high-speed 

data block demultiplexer E06 

Space Flight Operations Facility IBM 360/75 

user device switching assemblies HOI 

Ground Communications Facility wideband digital 

data system terminal configuration H06 

isoperimetric problems in integrated-circuit layout Hll 

evaluation of recording tape and heads for spacecraft H20 

KOI 
S26 

ion thruster connectors H24 

digital clean-up loop transponder for sequential 

ranging system H27 

calibration of Mariner Mars 1971 scan proof -test model J13 

Viking orbiter system articulation control subsystem J14 

switched-carrier experiments K09 

radiation hardening techniques for a complementary- 
symmetry metal-oxide semiconductor field-effect 

transistor memory L17 



284 



Subject Entry 

Electronic Components and Circuits (contd) 
efEect of Jupiter electron dose on metal oxide 

semiconductors L18 

radiation effects on electronic parts M07 

polarization diverse S-band feed cone N02 

Ground Communications Facility high-speed 

communications system N04 

teletype line switching equipment P03 

circuit for terminated capacitor discharge firing 

of electroexplosive devices R15 

nonlinear analysis of an absolute value type of 

early-late gate bit synchronizer S33 

group delay measurements of Deep Space Instrumentation 

Facility receiver-exciter modules S54 

Deep Space Network programmed oscillators WIO 

digital modulator W16 

Energy Storage 

sterilizable battery development BOS 

C31 

reaction geometry of alkaHne silver electrode J22 

permeability of membranes L25 

development of a long-life high-cycle-life 
30 A-h sealed AgO-Zn battery P05 

Facility Engineering 

upgrading of deep space stations B24 

Robledo Deep Space Station (DSS 61/63) facility 

modifications and construction CIO 

Mars Deep Space Station (DSS 14) 210-ft-diam antenna 

hydrostatic bearing runner level reference GOl 

Ground Communications Facility wideband digital 

data system terminal configuration HOB 

Venus Deep Space Station (DSS 13) operations JOl 

85-ft-diam antenna tracking station powerplant 

reconfiguration K15 

Mars Deep Space Station (DSS 14) 210-ft-diam antenna 

thrust collar survey L24 

Ground Communications Facility functional design 

for 1971-1972 MIO 

Ground Communications Facility high-speed 

communications system N04 

antenna facility operations in support of Pioneer VI RIO 

functional design of Space Flight Operations Facility 

for 1970-1972 era S28 



285 



Subject Entry 

Fluid Mechanics 

changes in heat transfer from turbulent boundary layers 

interacting with shock waves and expansion waves BOl 

relationship between temperature and velocity profiles 

in a turbulent boundary layer along a supersonic 

nozzle with heat transfer B02 

experiments relating popping and resonant combustion 

to stagnation dynamics of injection impingement 

in liquid rocket engines C22 

injector hydrodynamics effects on baffled-engine 

stability: correlation of required baffle geometry 

with injected mass flux C23 

response of supersonic laminar boundary layer to a 

moving external pressure field M03 

Industrial Processes and Equipment 
fabrication development of lightweight 

honeycomb-sandwich structures NOl 

Information Theory 

application of nonadaptive transversal filters to 

playback of digital tape recorder signals A08 

signal design for single-sideband phase modulation Cll 

command prefix code for Thermoelectric 

Outer-Planet Spacecraft (TOPS) D04 

concatenation of short-constraint-length convolutional codes E04 

optimality of all-digital command system timing loop H23 

digital clean-up loop transponder for sequential 

ranging system H27 

performance of a phase-locked loop during 

loss of signal H28 

error rates for data words time-multiplexed 

onto 6-bit block-coded words J19 

Viking orbiter-lander relay link multipath simulation J20 

optimum performance of two-channel high-rate 

interplex systems L04 

analysis of optimum squaring loop prefilter LOS 

effect of loop stress on performance of phase-coherent 

communications systems L20 

weight distributions of irreducible cyclic codes M13 

standard run-length coding for multi-level sources M27 

spectral factorization in discrete systems • N06 

decomposition of states of linear feedback shift 

register into cycles of equal length Pll 

use of m-ary linear feedback shift registers 

with binary devices P12 



286 



Subject Entry 

Information Theory (contd) 

use of sequential estimation with process noise 

for processing tracking data R22 

stabihty of second-order tracking loops with 

arbitrary time delay S29 

steady-state performance of a data-transition 

type of first-order digital phase-locked loop S30 

optimum modulation index for a data-aided 
phase-coherent communication system S31 

nonlinear analysis of an absolute value type 

of early-late gate bit synchronizer S33 

asymptotic formula for mean cycle-slip time of second- 
order phase-locked loop with frequency offset T05 

efficiency of biphase-modulated subcarriers for 
N-channel telemetry systems T08 

equivalence of time-multiplex and phase-shift-keyed 

signals for digital communication T09 

optimum configurations for phase-shift-keyed/phase- 
modulated systems TIO 

critical problem of combinatorial geometry 

and coding theory W09 

matched filters for binary signals Z04 

Launch Operations 

Mariner Mars 1969 Project launch operations J07 

Launch Vehicles 

Mariner Mars 1969 launch vehicle performance J07 

Lunar Interior 

lunar elevation correction for gravity measurements B22 

significance of Surveyor V chemistry experiments 

to theory of lunar interior G09 

Lunar Motion 

preliminary special perturbation theory for lunar motion G04 

polynomial expressions for lunar motion S52 

Lunar Orbiter Project 

Lunar Orbiter spacecraft photographs of regional 
lunar geological settings of Surveyor spacecraft 
landing sites M30 

Lunar Spacecraft, Advanced 

computerized landmark navigator L15 

Lunar Surface 

lunar post-sunset horizon afterglow observed 

by Surveyor spacecraft G07 

significance of Surveyor V chemistry experiments 

to theory of lunar interior G09 



287 



Subject Entry 

Lunar Surface (contd) 

physical condition of lunar surface from 

Surveyor spacecraft observations GIO 

M32 
S19 

science results from Surveyor Project JOS 

changes on lunar surface during 31 months determined 

from comparison of Surveyor III and Apollo 12 

photographs J04 

regional geological settings of Surveyor 

spacecraft landing sites M30 

craters observed by Surveyor spacecraft M31 

chemical analysis of lunar surface from 

Surveyor spacecraft data P14 

revised lunar surface thermal characteristics 

from Surveyor V data S46 

Management Systems 

Space Flight Operations Facility configuration control C09 

Deep Space Network user requirements forecast R17 

Deep Space Network data path status code R20 

Deep Space Network command system analysis group S47 

Mariner Mars 1969 Project 
observational patrol of Mars in support 

of Mariners VI and VII C07 

navigation data from television pictures DIO 

determination of Mariner VI and VII flight 

paths from tracking data Gil 

Mariner VI and VII in-flight maneuvers Gil 

launch operations J07 

launch vehicle performance J07 

Mariner VI and VII flight dynamic environment J07 

Mariner VI and VII fhght path and navigation J07 

Mariner VI and VII flight performance J07 

scientific instrument performance J07 

probe of solar plasma by Mariner VI and VII 

radio metric data MOl 

tracking system analytical calibration M39 

navigation, control, and guidance Sll 

Mariner Mars 1971 Project 

modeling of peripheral belt drive magnetic tape recorder JOS 

mission and test computer system JIO 

codispersion propellant expulsion bladder evaluation Jll 

evaluation of spacer rod material for 

narrow-angle television camera Jll 

spacecraft mass property determination Jll 



288 



Subject Entry 

Mariner Mars 1971 Project (contd) 

structure and dynamics test and analysis Jll 

calibration of scan proof-test model J13 

sizing results for attitude-control gas nozzles J13 

project description and status J15 

effect of solvent on biaxial properties of liquid 

propellant expulsion Teflon bladder bags J17 

propulsion subsystem J17 

Deep Space Network support LOS 

Mariner Venus-Mercury 1973 Project 

500-h irradiation test of solar array components JOS 

project description and status J16 

imaging experiment J18 

thermal radiative characteristics of solar arrays 

determined by calorimetric techniques W06 

Masers and Lasers 

superconducting magnet for X-band maser B14 

microwave maser development C21 

atomic hydrogen maser frequency standard F02 

proposed laser obstacle detection sensor for a Mars rover K13 

diffraction of a high-order gaussian 

laser beam by an aperture L21 

holographic study of operating xenon compact-arc lamp M18 

Materials, Metallic 

mesh materials for deployable antennas F03 

evaluation of spacer rod material for Mariner Mars 

1971 narrow-angle television camera Jll 

crack propagation threshold for isopropanol and 

Ti-6A1-4V titanium alloy pressure vessels L14 

materials for lightweight honeycomb-sandwich structures NOl 

evaluation of radioisotope thermoelectric 

generator materials R16 

reflector surface materials for spacecraft antennas W19 

effects of high-temperature, high-humidity 

environment on silicon solar cell contacts Y05 

Materials, Nonmetallic 

effects of lithiimi doping on behavior of sihcon BlI 

activation energy of annealing in lithium-doped silicon B13 

superposition of dynamic mechanical properties 

in glassy state of polymers C29 

electrical properties of TCNQ salts of ionene 

polymers and their model compounds H03 

Mariner Mars 1971 codispersion propellant 

expulsion bladder evaluation Jll 



289 



Subject Entry 

Materials, Nonmetaliic (co.ntd) 

effect of solvent on biaxial properties of liquid 

propellant expulsion Teflon bladder bags for 

Mariner Mars 1971 spacecraft J17 

viscoelastic behavior of elastomers undergoing 

crosslinking reactions M26 

composite-beam testing M44 

materials for lightweight honeycomb-sandwich structures NOl 

energy transfer in bipyridilium (paraquat) salts R07 

spacecraft adhesives for long life and extreme environment R13 

reilector surface materials for spacecraft antennas W19 

Mathematical Sciences 

modeling of equivalent spring-mass system 

for normal modes B04 

signal design for single-sideband phase modulation Cll 

expressions for spacecraft antenna tolerances D02 

estimating the parameter of an exponential 

distribution using quantiles E02 

solution of partial differential systems EOS 

a real variable lemma and the continuity of 

paths of some gaussian processes GOB 

automatic error bounds for real roots of polynomials 

having interval coefBcients H09 

unitary similarity transformation of a Hermitian 

matrix to a real symmetric tridiagonal matrix HIO 

isoperimetric problems in integrated-circuit layout Hll 

optimum pressure vessel design based on fracture 

mechanics and reliability criteria H16 

numerical techniques for calculation of Hottel £?-factor 

and radiosity in thermal design analysis H26 

general solution to problem of performance of a 

phase-locked loop during loss of signal H28 

analysis of error rates for data words time-multiplexed 

onto 6-bit block-coded words J19 

system model for analysis of optimum performance 

of two-channel high-rate interplex systems L04 

analysis of optimum squaring loop prefilter LOS 

finite element modeling for appendage interaction 

with spacecraft attitude control L19 

analysis of effect of loop stress on performance 

of phase-coherent communications systems L20 

derivation of intensity of a high-order gaussian beam as a 

function of aperture size and oscillating mode index L21 

linear equations of motion and stability analysis 

relative to attitude conti-ol of a flexible solar-electric 

spacecraft M05 



290 



Subject Entry 

Mathematical Sciences (contd) 

computation of weight distributions of 

irreducible cyclic codes M13 

formulation of electromagnetic wave propagation 

properties in a uniformly accelerated simple medium M22 

spectral factorization in discrete systems N06 

analysis of decomposition of linear feedback shift 

register into cycles of equal length Pll 

exact solution of linear eigenvalue problem used to 

study effect of elastic end rings on eigenfrequencies 

of finite length thin cylindrical shells ROl 

use of sequential estimation with process noise 

for processing tracking data R22 

analysis of stability of second-order tracking loops 

with arbitrary time delay S29 

analysis of steady-state performance of a data- 
transition type of first-order digital phase-locked loop S30 

nonlinear analysis of an absolute value type of 

early-late gate bit synchronizer S33 

polynomial expressions for planetary equators and 

orbit elements with'respect to the mean 1950.0 

coordinate system S52 

two-body kinematics used to calculate neutron yield 

from (a,n) reaction with O^** istotope TOl 

choice of integrators for use with 

variation-of -parameters formulation T02 

asymptotic formula for mean cycle-slip time of 

second-order phase-locked loop with frequency offset T05 

optimum configurations for phase-shift- 
keyed/phase-modulated systems TIO 

optimal methods for computing the incomplete 

gamma and related functions W08 

critical problem of combinatorial 

geometry and coding theory W09 

derivation of equations governing heated 

shallow shells of revolution W14 

Mechanics 

equivalent spring-mass system for normal modes B04 

lunar elevation correction for gravity measurements B22 

Mariner VI and VII flight dynamic environment J07 

Mariner Mars 1971 spacecraft mass property determination Jll 

Mariner Mars 1971 structure and dynamics 

test and analysis JH 

finite element modeling for appendage interaction 

with spacecraft attitude control L19 



291 



Subject Entry 

Mechanics (contd) 
linear equations of motion and stability analysis relative to 
attitude control of a flexible solar-electric spacecraft M05 

Mechanisms 

modeling of peripheral belt drive magnetic tape 

recorder for Mariner Mars 1971 spacecraft JOS 

Viking launch vehicle-orbiter-lander 

separation interfaces J12 

mechanical devices for Thermoelectric 

Outer-Planet Spacecraft (TOPS) SOI 

Meteors 

science results from Surveyor Project JOS 

micrometeoroid flux on lunar surface determined from 

comparison of Surveyor III and Apollo 12 photographs J04 

Optics 
telescopic equipment used in observational patrol 

of Mars in support of Mariners VI and VII COl 

evaluation of spacer rod material for Mariner Mars 1971 

narrow-angle television camera Jll 

diffraction of a high-order gaussian beam by an aperture L2] 

holographic study of operating xenon compact-arc lamp Ml£ 

saturation of stellar scintillation YOS 

Packaging and Cabling 
Deep Space Instrumentation Facility integrated-circuit 

packaging system for telemetry data decoder A06 

evaluation of 26- to 32-AWG (American wire gauge) 

wire for outer-planet mission applications A07 

Deep Space Network Mark III development C24 

packaging of Deep Space Network Block IV 

receiver-exciter D06 

isoperimetric problems in integrated-circuit layout Hll 

Particle Physics 

relative proton aflSnity of argon and deuterium B18 

interaction between an electron wave and an ion wave 

due to scattering by electrons N05 

neutron yield from (a,n) reaction with O^* isotope TOl 

Photography 

video image display assembly DOS 

navigation data from Mariner Mars 1969 

television pictures DIO 

lunar post-sunset horizon afterglow photographed 

by Surveyor spacecraft G07 

Surveyor television instrument design and 

mission operations J02 



292 



Subject Entry 

Photography (contd) 

evaluation of spacer rod material for Mariner Mars 1971 

narrow-angle television camera JU 

Mariner Venus-Mercury 1973 imaging experiment J18 

holographic study of operating xenon compact-arc lamp M18 

Surveyor lunar photographs M30 

M31 

M32 

discernibility of cathode-ray tube gray shades VOX 

Pioneer Project 

Tracking and Data System support for Pioneer VI RIO 

Deep Space Network support S23 

quasi-stationary solar coronal magnetic field 

and electron density as determined from 

Faraday rotation experiment by Pioneer VI S45 

Planetary Atmospheres 

observational patrol of Mars atmosphere in support 

of Mariners VI and WI C07 

multi-phase ammonia-water system for modeling 

Jupiter and Saturn atmospheres H14 

Mariner Venus-Mercury 1973 imaging experiment J18 

high-resolution spectra of Venus Yll 

Y12 
improved constants for 7820- and 7883-A bands of 

CO, derived from Venus atmosphere Y13 

Planetary Exploration, Advanced 

radioisotope thermoelectric generators for 

outer-planet missions COS 

proposed laser obstacle detection sensor for a Mars rover K13 

effect of Jupiter electron dose on metal 

oxide semiconductors LIS 

thrust subsystem design for nuclear-electric 

Jupiter orbiter M08 

evaluation of radioisotope thermoelectric 

generators for outer-planet missions R16 

Planetary Motion 
polynomial expressions for planetary equators and 
orbit elements with respect to the mean 1950.0 
coordinate system S52 

Planetary Spacecraft, Advanced 

evaluation of 26- to 32-AWG (American wire gauge) 

wire for outer-planet mission applications A07 

inertial and gyrocompass/odometer navigators 

for roving vehicle navigation subsystem L16 



293 



Subject Entry 

Planetary Spacecraft, Advanced (contd) 

hardening techniques for a complementary-symmetry 

metal-oxide semiconductor field-effect 

transistor memory L17 

evaluation of radioisotope thermoelectric generators 

for outer-planet missions R16 

approach guidance sensor subsystem .S40 

Planetary Surfaces 

observational patrol of Mars surface in support 

of Mariners V7 and VII C07 

Mariner Venus-Mercury 1973 imaging experiment J18 

Plasma Physics 

experimental study of magnetic flux transfer 

at hyperbolic neutral point B20 

interaction between an electron wave and an ion 

wave due to scattering by electrons N05 

heat transfer from partially ionized argon 

flowing in conducting channel with applied 

transverse magnetic field R14 

theoretical considerations of prebreakdown 

characteristics in a cesium thermionic discharge S14 

Power Sources 

efi^ects of lithium doping on behavior 

of silicon solar cells Bll 

activation energy of annealing in lithium-doped 

silicon used for solar cells B13 

radioisotope thermoelectric generators for 

outer-planet missions COS 

electric propulsion power conditioning C27 

lightweight solar panels H13 

500-h irradiation test of Mariner Venus-Mercury 

1973 solar array components JOS 

cracking of filter layers in a high-performance 

solar cell filter J06 

comparison of calculated and experimentally 

measured performance of thermoelectric generator Lll 

evaluation of radioisotope thermoelectric generators 

for outer-planet missions R16 

capacitance of solar cells under various load conditions SOS 

theoretical considerations of prebreakdown 

characteristics in a cesium thermionic discharge S14 

evaluation of a SNAP-19 (System for Nuclear 

Auxiliary Power 19) thermoelectric generator 

made with new P-leg material S41 



294 



Subject Entry 

Power Sources (contd) 

radiation damage in lithium-doped silicon solar cells S48 

S49 
optimization and reliability calculations for 

multi-thermionic-converter systems S55 

neutron yield from (a,n) reaction with O^^ isotope 

in radioisotope thermoelectric generator TOl 

thermal radiative characteristics of solar arrays 

determined by calorimetric techniques W06 

effects of high-temperature, high-humidity 

environment on silicon solar cell contacts Y05 

Propulsion, Electric 

power conditioning C27 

stepper motor drive electronics for solar-electric 

thrust vector control subsystem C28 

ion thruster connectors H24 

attitude control of a flexible solar-electric spacecraft M05 

thrust subsystem design for nuclear-electric spacecraft M08 

performance of 20-cm-diam electron-bombardment 

hollow-cathode ion thruster P06 

ion thruster electron baffle sizing P07 

ion thruster using combination keeper 

electrode and electron baffle P08 

Propulsion, Liquid 

experiments relating popping and resonant combustion 

to stagnation dynamics of injection impingement C22 

injector hydrodynamics effects on baffled-engine 

stability: correlation of required baffle 

geometry with injected mass flux C23 

optimum pressure vessel design based on fracture 

mechanics and reliability criteria H16 

Mariner Mars 1971 codispersion propellant 

expulsion bladder evaluation Jll 

effect of solvent on biaxial properties of liquid 

propellant expulsion Teflon bladder bags for 

Mariner Mars 1971 spacecraft J17 

Mariner Mars 1971 propulsion subsystem J17 

testing of component storage with propellants K05 

M02 
crack propagation threshold for isopropanol and 

Ti-6Al-4V titanium alloy used for spacecraft 

pressure vessels LI4 

high-thrust throttleable monopropellant 

hydrazine reactors FI6 

creep failure of randomly excited pressure vessels ¥03 



295 



Subject Entry 

Propulsion, Solid 
structural analysis of a solid propellant motor under 

axisymmetric thermal and pressure loading C19 

viscoelastic behavior of elastomers undergoing 

crosslinking reactions M26 

microwave m easurement of solid propellant burning rates N08 

low pressure/low motor free volume to nozzle 

throat area ratio combustion limits S51 

Pyroteclmics 
Viking launch vehicle-orbiter-lander 

separation interface J12 

nondestructive testing of pyrotechnic devices M17 

terminated capacitor discharge firing of 

electroexplosive devices R15 

Quality Assurance and Reliability 

evaluation of 26- to 32-AWG (American wire gauge) 

wire for outer-planet mission applications A07 

estimation of the parameter of an exponential distribution 

using quantiles for reliability estimation E02 

optimum pressure vessel design based on fracture 

mechanics and reliability criteria H16 

evaluation of spacecraft magnetic recording 

tapes and magnetic heads KOI 

testing of component storage with propellants K05 

M02 

radiation effects on electronic parts M07 

evaluation of radioisotope thermoelectric generators 

for outer-planet missions R16 

optimization and reliability calculations for 

multi-thermionic-converter systems S55 

reliability of randomly excited structures . . .' Y04 

Kadar 

Venus Deep Space Station (DSS 13) planetary 

radar experiments JOl 

tau ranging subsystem rebuild T03 

digital modulator for planetary radar W16 

Radio Astronomy 

interstellar scintillations of pulsar signals at 2388 MHz DOS 

Deep Space Network radio science support S02 

Relativity 

Mariner VI and VII relativity experiment MOl 

electromagnetic wave propagation in a uniformly 

accelerated simple medium M22 

very long baseline interferometry experiment on 

radio sources to test theory of general relativity S02 



296 



Subject Entry 

Scientific Instruments 

Surveyor scientific instrument designs 

and mission operations J02 

Mariner Mars 1969 scientific instrument performance J07 

Pioneer VI scientific instruments RIO 

Shielding 

radiation hardening techniques for a complementary- 
symmetry metal-oxide semiconductor field-effect 
transistor memory L17 

radioisotope thermoelectric generator shielding 

requirements for outer-planet missions R16 

Soil Sciences 

isolation and characterization of coal 

in Antarctic dry-valley soils B09 

soil microbial and ecological investigations 

in the Antarctic interior C02 

significance of Surveyor V chemistry experiments 

to theory of lunar interior G09 

physical condition of lunar surface from 

Surveyor spacecraft observations GIO 

science results from Surveyor Project JOS 

microbiological analyses of snow and air 

from Antarctic interior L02 

regional lunar geological settings of Surveyor 

spacecraft landing sites M30 

lunar craters observed by Surveyor spacecraft M31 

lunar fragmental debris observed by 

Surveyor spacecraft M32 

chemical analysis of lunar surface from Surveyor 

spacecraft data P14 

physics of lunar fragmental debris observed 

by Surveyor spacecraft 819 

Solar Phenomena 

science results from Surveyor Project JOS 

narrow-band solar spectral irradiance measured at 

75 km above sea level with multichannel radiometer L06 

probe of solar plasma by Mariner VI and VII 

radio metric data MOl 

quasi-stationary coronal magnetic field 

and electron density as determined from 

Faraday rotation experiment S45 

improved solar wavelengths for spectrometry 

between 7780 and 7925 A YIO 



297 



Subject Entry 

Solid-State Physics 
user's manual for VISCEL, a general-purpose 

computer program for analysis of linear 

viscoelastic structures A04 

effects of lithium doping on behavior of silicon Bll 

activation energy of annealing in lithixma-doped silicon B13 

superposition of dynamic mechanical properties 

in glassy state of polymers C29 

optimum pressure vessel design based on fracture 

mechanics and reliability criteria H16 

crack propagation threshold for isopropanol and 

Ti-6A1-4V titanium alloy pressure vessels L14 

viscoelastic behavior of elastomers undergoing 

crosslinking reactions M26 

composite-beam testing M44 

effect of elastic end rings on eigenfrequencies 

of finite length thin cylindrical shells ROl 

radiation damage in lithium-doped silicon solar cells S48 

S49 
boundary layer equations of a heated 

constrained spherical shell W13 

derivation of equations governing heated 

shallow shells of revolution W14 

creep failure of randomly excited structures Y03 

reliability of randomly excited structures Y04 

effects of high-temperature, high-humidity 

environment on silicon solar cell contacts Y05 

Spectrometry 

inverse problems in radiative transfer: determination 

of atmospheric parameters C12 

transition probabilities for Xe I C18 

infrared spectrometry used to test radiation damage 

in lithium-doped silicon solar cells S49 

improved solar wavelengths between 7780 and 7925 A YIO 

high-resolution spectra of Venus Yll 

Y12 
improved constants for 7820- and 7883-A bands of CO, Y13 

Standards, Reference 
polar motion: doppler determination using 

satellites compared to optical results C17 

atomic hydrogen maser frequency standard F02 

deep space station location solutions and timing 

and polar motion considerations in determination 

of Mariner VI and VII flight paths from tracking data Gil 

Deep Space Network Inherent Accuracy Project H04 



298 



Subject Entry 

Standards, Reference (contd) 

calibration of Mariner Mars 1971 scan proof -test model J13 

tracking system analytical calibration for 

Mariner Mars 1969 Project M39 

polynomial expressions for planetary equators and orbit 

elements with respect to the mean 1950.0 

coordinate system S52 

IBM 360/75 computer time interface ZOl 

IBM 360/75-Umvac 1108 computer interface for 

synchronous use without modems Z02 

Structural Engineering 

user's manual for VISCEL, a general-purpose computer 

program for analysis of linear viscoelastic structures A04 

equivalent spring-mass system for normal modes B04 

structural analysis of a solid propellant motor 

under axisymmetric thermal and pressure loading C19 

lightweight solar panels H13 

optimum pressure vessel design based on fracture 

mechanics and reliability criteria H16 

Mariner Mars 1971 structure and dynamics 

test and analysis Jll 

composite-beam testing M44 

fabrication development of lightweight 

honeycomb-sandwich structures NOl 

effect of elastic end rings on eigenfrequencies 

of finite length thin cylindrical shells ROl 

magnetometer boom for Thermoelectric 

Outer-Planet Spacecraft (TOPS) SOI 

creep failure of randomly excited structures y03 

reliability of randomly excited structures Y04 

Surveyor Project 

lunar post-sunset horizon afterglow observed 

by Surveyor spacecraft G07 

significance of Surveyor V chemistry experiments 

to theory of lunar interior G09 

physical condition of lunar surface from 

Surveyor spacecraft observations GIO 

spacecraft design and mission operations J02 

science results J03 

changes on Ixmar surface during 31 months determined 

from comparison of Surveyor III and Apollo 12 

photographs J04 

regional lunar geological settings of Surveyor 

spacecraft landing sites M30 

lunar craters observed by Surveyor spacecraft M31 



299 



Subject Entry 

Surveyor Project (contd) 

lunar f ragmental debris observed by Surveyor spacecraft M32 

chemical analysis of lunar surface from 

Surveyor spacecraft data P14 

physics of lunar fragmental debris 

observed by Surveyor spacecraft S19 

revised lunar surface thermal characteristics 

from Surveyor V data S46 

Telemetry and Command 

command prefix code for Thermoelectric 

Outer-Planet Spacecraft (TOPS) D04 

concatenation of short-constraint-length 

convolutional codes E04 

optimality of all-digital command system timing loop H23 

Viking orbiter system programmable 

f ormater for engineering telemetry J09 

error rates for data words time multiplexed 

onto 6-bit block-coded words J19 

Viking orbiter-lander relay Hnk multipath simulation J20 

Deep Space Network support of 

Mariner Mars 1971 Project LOS 

optimum performance of two-channel 

high-rate interplex systems L04 

optimum squaring loop prefilter L08 

effect of loop stress on performance of 

phase-coherent communications systems L20 

computing weight distributions of 

irreducible cyclic codes M13 

standard run-length coding for multi-level sources M27 

Deep Space Network support of Viking Project M37 

inbound high-speed and wideband data synchronizers P09 

decomposition of states of linear feedback shift 

register into cycles of equal length Pll 

Deep Space Network functions and facilities R09 

Tracking and Data System support for Pioneer VI RIO 

Deep Space Network data path status code R20 

Deep Space Network support of Pioneer Project S23 

functional design of Space Flight Operations 

Facility for 1970-1972 era S28 

steady-state performance of a data-transition type 

of first-order digital phase-locked loop S30 

optimum modulation index for a data-aided 

phase-coherent communication system 831 

nonlinear analysis of an absolute value type 

of early-late gate bit synchronizer 833 



300 



Subject E"*fy 

Telemetry and Command (contd) 

Deep Space Network command system analysis group S47 

asymptotic formula for mean cycle-slip time of 

second-order phase-locked loop with frequency offset T05 

efficiency of biphase-modulated subcarriers 
for IV-channel telemetry systems T08 

equivalence of time-multiplex and phase-shift-keyed 
signals for digital communication T09 

optimum configurations for phase-shift- 
keyed/phase-modulated systems TIO 

digital modulator for greater reliability 

of command system W16 

matched filters for binary signals Z04 

Temperature Control 

thermal modeling of spacecraft with imperfect models C13 

user's manual for Thermal Analysis 

System I computer program H26 

scientific instrument heat control pump for 

Thermoelectric Outer-Planet Spacecraft (TOPS) SOI 

thermal radiative characteristics of solar arrays 

determined by calorimetric techniques W06 

Test Facilities and Equipment 

equipment for testing relationship of liquid rocket 

engine popping and resonant combustion to 

stagnation dynamics of injection impingement €22 

equipment for testing Thermoelectric Outer -Planet 

Spacecraft (TOPS) attitude-control single-axis simulator FOl 

equipment for testing mesh materials for 

deployable antennas F03 

Thermoelectric Outer-Planet Spacecraft (TOPS) 

attitude-control single-axis simulator 

true position encoder G12 

holographic study of solar simulation arc lamps M18 

equipment for microwave measurement of 

solid propellant burning rates N08 

equipment for calibration of RF properties 

of 210-ft-diam antenna mesh Oil 

equipment for determining heat transfer from 

partially ionized argon flowing in conducting 

chaimel with apphed transverse magnetic field R14 

equipment for testing radioisotope 

thermoelectric generators R16 

circuits for measuring capacitance of solar cells 

under various load conditions SOS 



301 



Subject Entry 

Test Facilities and Equipment (contd) 

equipment for determining thermal radiative characteristics 

of solar arrays by calorimetric techniques W06 

device for testing reflector surface 

materials for spacecraft antennas W19 

Thermodynamics 

changes in heat transfer from turbulent 

boundary layers interacting with shock 

waves and expansion waves BOl 

relationship between temperature and velocity 

profiles in a turbulent boundary layer along 

a supersonic nozzle with heat transfer B02 

user's manual for Thermal Analysis 

System I computer program H26 

shock tube thermochemistry tables for 

high-temperature gases M15 

heat transfer from partially ionized argon 

flowing in conducting channel with applied 

transverse magnetic field R14 

revised lunar surface thermal characteristics 

from Surveyor V data S46 

boundary layer equations of a heated 

constrained spherical shell W13 

derivation of equations governing heated 

shallow shells of revolution W14 

Thermoelectric Outer-Planet Spacecraft (TOPS) 

command prefix code Jl)04 

attitude-control single axis simulator FOl 

attitude-control single-axis simulator 

true position encoder G12 

digital gyro system for single-axis simulator H05 

hardening techniques for a complementary- 
symmetry metal-oxide semiconductor 
field-effect transistor memory L17 



Subject Entry 

Tracking 
polar motion: doppler determination using 

satellites compared to optical results C17 

Deep Space Network Block IV 

receiver-exciter development DOB 

determination of Mariner VI and VII flight 

paths from tracking data Gil 

Deep Space Network Inherent Accuracy Project H04 

digital clean-up loop transponder for 

sequential ranging system H27 

performance of a phase-locked loop during loss of signal H28 

Deep Space Network support of 

Mariner Mars 1971 Project LOS 

sensitivity of tropospheric range and doppler 

effects to shape of refractivity profile M19 

Deep Space Network support of Viking Project M37 

tracking system analytical calibration 

for Mariner Mars 1969 Project M39 

spectral factorization in discrete systems N06 

Deep Space Network functions and facilities R09 

Tracking and Data System support for Pioneer VI RIO 

Deep Space Network data path status code R20 

use of sequential estimation with process 

noise for processing tracking data R22 

Deep Space Network support of Pioneer Project S23 

functional design of Space Flight Operations 

FaciHty for 1970-1972 era S28 

stability of second-order tracking loops 

with arbitrary time delay S29 

steady-state performance of a data-transition 

type of first-order digital phase-locked loop S30 

optimization of performance of 

digital-data-transition tracking loop S34 

group delay measurements of Deep Space Instrumentation 

Facility receiver-exciter modules S54 

tau ranging subsystem rebuild T03 

second/third-order hybrid phase-locked 

receiver for tracking doppler rates T04 

optimum configurations for phase-shift- 
keyed/phase-modulated systems TIO 

refractivity influence on doppler data W17 

Trajectory Analysis/Orbit Determination 

navigation data from Mariner Mars 1969 

television pictures DIO 



303 



Subject Entry 

Trajectory Analysis/Orbit Determination (contd) 
determination of Mariner VI and VII flight 

paths from tracking data Gil 

Mariner Mars 1969 spacecraft navigation J07 

system of computer programs for 

interactive trajectory design K06 

Mariner Mars 1969 Project tracking system 

analytical calibration to determine 

uncertainties in navigational accuracy M39 

polynomial expressions for planetary equators and 

orbit elements with respect to the mean 1950.0 

coordinate system S52 

choice of integrators for use with 

variation-of -parameters formulation T02 

Viking Project 

orbiter system programmable formater 

for engineering telemetry J09 

launch vehicle-orbiter-Iander separation interfaces J12 

orbiter system articulation control subsystem J 14 

orbiter system sun occultation logic and 

sun sensor null detector J14 

orbiter-lander relay link multipath simulation J20 

project description and status J21 

Deep Space Network support M37 

Voice Communications 

Ground Communications Facility 

voice system for 1971-1972 MIO 

Ground Communications Facility control group 

assembly voice data switching equipment P04 

Wave Propagation 

signal design for single-sideband phase modulation Cll 

spacecraft antenna tolerances D02 

digital clean-up loop transponder for 

sequential ranging system H27 

performance of a phase-locked loop during loss of signal H28 

switched-carrier experiments K09 

electromagnetic wave propagation in a uniformly 

accelerated simple medium M22 

tracking system analytical calibration 

for Mariner Mars 1969 Project M39 

optimum configurations for phase-shift 

keyed/phase modulated systems TIO 



304 



Publication Index 

Technical Reports 

Number Entry 

32-1351, Pt. II C12 

32-1408, Vol. IV M15 

32-1416 H26 

32-1460, Vol. II J07 

32-1473 NOl 

32-1479 C22 

32-1489 ROl 

32-1492 C07 

32-1495 R16 

32-1497 H09 

32-1499 M39 

32-1508 S52 

32-1509 C29 

32-1510 R14 

32-1511 PH 

32-1512 M24 

32-1514 BU 

32-1517 G04 

32-1520 Y05 

32-1521 R15 

32-1523 POl 



305 



DSN Progress Report for November-December 1970 

(Technical Report 32-1526, Vol. I) 

JPL Technical Section Entry 

315 Flight Operations and DSN Programming T02 

W17 

316 SFOF/GCF Operations C09 

318 SFOF/GCF Development L09 

P03 
P09 

S27 

W05 

ZOl 

Z02 

330 Telecommunications Division T04 

331 Communications Systems Research E04 

MOl 

W16 

Z04 

332 DSIF Engineering K04 

L13 

333 Communications Elements Research F02 

N02 

390 Mission Analysis Division H04 

391 Tracking and Orbit Determination H04 

MOl 
M19 
W17 

420 Mission Support L03 

M37 
R09 



Technical Memorandums 

Number Entry 

33-380 B04 

33-426, Vol. V RIO 



306 



Number Entry 

33-464 S05 

33-466, Vol. I A04 

33-468 P06 

33-469 Gil 

33-470 H16 

33-472 H17 



Space Programs Summary 37-65, Vol. Ill 

J PL Technical Section Entry 

131 Advanced Studies .L15 

314 Computation and Analysis W08 

315 Flight Operations and DSN Programming K06 

324 Science Data Analysis B19 

331 Communications Systems Research BIO 

H23 
L04 
M13 
M27 
T08 
T09 

333 Communications Elements Research B14 

W19 
W20 

342 Spacecraft Power BOS 

B13 
C27 
H13 
J22 
Lll 
L25 
P05 
S41 
TOl 



307 



JPL Technical Section Entry 

343 Guidance and Control Analysis and Integration L15 

L16 
O04 
P02 
S14 
S40 
S48 
S49 

344 Spacecraft Control FOl 

G12 

351 Materials F03 

J05 
L14 

353 Applied Mechanics C13 

C19 
W06 

357 Electronic Packaging and Cabling A07 

363 Spacecraft Data Systems A08 

KOI 
L17 

373 Aerophysics M04 

375 Space Simulation L06 

381 Solid Propellant Engineering N08 

382 Polymer Pieseardi C19 

C31 
KOI 

384 Liquid Propulsion K05 

M02 

391 Tracking and Orbit Determination M22 



Space Programs Summary 37-66, Vol. I 

JPL Technical Section Entry 

210 Mariner Mars 71 Project J15 

220 Viking Orbiter J21 

250 Mariner Venus-Mercury 73 Project J16 



308 



JPL Technical Section Entry 

310 Data Systems Division JIO 

314 Computation and Analysis JIO 

321 Space Photography J18 

339 Spacecraft Telecommunications Systems JIO 

J20 

344 Spacecraft Control J13 

J14 

350 Engineering Mechanics Division Jll 

J12 

351 Materials Jll 

353 Applied Mechanics JOS 

Jll 

355 Advanced Projects Development Jll 

JB 

362 Spacecraft Measurements J09 

363 Spacecraft Data Systems JOS 

382 Polymer Research J17 

384 Liquid Propulsion J17 



Space Programs Summary 37-66, Vol. II 

JPL Technical Section Entry 

318 SFOF/GCF Development DOS 

E06 
HOI 
HOB 
MIO 
N04 
P04 
S28 
S50 

vol 

W12 
330 Telecommunications Division T05 



309 



JPL Technical Section Entry 

331 Communications Systems Research A06 

E02 
Hll 
S54 

332 DSIF Engineering B24 

CIO 
GOl 
K15 
L24 

333 Communications Elements Research B07 

C21 
Mil 
Oil 
R03 
R05 
S02 

335 R. F. Systems Development C24 

D06 

JOl 

K09 

WIO 

337 DSIF Operations S02 

338 DSIF Digital Systems Development B23 

T03 
WOT 

391 Tracking and Orbit Determination C17 

R22 

401 DSN Engineering and Operations R17 

R20 

S47 

420 Mission Support S23 



Space Programs Summary 37-66, Vol. Ill 

JPL Technical Section Entry 

131 Advanced Studies B22 

294 Environmental Requirements H14 

LIS 



310 



J PL Technical Section Entry 
314 Computation and Analysis HIO 

328 Physics E05 

M03 

331 Communications Systems Research H27 

H28 

TIO 

W09 

333 Communications Elements Research D02 

339 Spacecraft Telecommunications Systems Cll 

829 
S30 
831 

342 Spacecraft Power COS 

343 Guidance and Control Analysis and Integration K13 

855 
W15 

344 Spacecraft Control C28 

H05 
L19 
M05 

351 Materials F04 

J06 
R13 

353 Applied Mechanics W13 

W14 
Y03 
Y04 

354 Electronic Parts Engineering M07 

355 Advanced Projects Development SOI 

S42 

363 Spacecraft Data Systems D04 

H20 
LIB 
P12 
826 

375 Space Simulation MIS 

381 Solid Propellant Engineering L21 

M17 
851 



311 



JPL Technical Section Entry 

382 Polymer Research H03 

H20 

M26 
R07 
S26 

383 Research and Advanced Concepts H24 

M08 
P07 
P08 

384 Liquid Propulsion C23 

P16 

391 Tracking and Orbit Determination N06 



Open Literature Reporting 

AIAA J. Entry 

Vol. 8, No. 10, pp. 1871-1873 BOl 

Vol. 8, No. 11, pp. 2066-2069 B02 



Antarc. J. U.S. Entry 

Vol. V, No. 4, pp. 87-88 C02 

Vol. V, No. 4, pp. 88-89 L02 

Vol. V, No. 5, pp. 161-162 B09 



Astrophys. J. Entry 
Vol. 163, No. 1, Pt. 2, pp. L11-L16 DOS 

Automatica Entry 
Vol. 6, No. 5, pp. 755-766 Sll 

Icarus: Int. J. Sol. Sys. Entry 

Vol. 12, No. 2, pp. 145-155 J02 

Vol. 12, No. 2, pp. 156-160 J03 

Vol. 12, No. 2, pp. 161-166, 211-212 M30 

Vol. 12, No. 2, pp. 167-172, 211-212 M31 

Vol. 12, No. 2, pp. 17S-187, 211-212 M32 

Vol. 12, No. 2, pp. 188-212 S19 

Vol. 12, No. 2, pp. 213-223 P14 



312 



Icarus: Int. J. Sol. Sys. (contd) Entry 

Vol. 12, No. 2, pp. 224-225 GOO 

Vol. 12, No. 2, pp. 226-229 GIO 

Vol. 12, No. 2, pp. 230-232 G07 

Vol. 13, No. 1, pp. 74-81 Yll 

Vol. 13, No. 2, pp. 270-275 Y12 



IEEE Trans. Commun. Technol. Entry 

Vol. COM-18, No. 5, pp. 569^88 L20 

Vol. COM-18, No. 5, pp. 589-596 S33 

Vol. COM-18, No. 5, pp. 686-689 S34 

Vol COM-18, No. 5, pp. 695-697 LOS 



Ind. Univ. Math. J. Entry 

Vol. 20, No. 6, pp. 565-578 .G02 

J. Am. Chem. Soc. Entry 

Vol. 92, No. 25, pp. 7258-7262 B18 

J. Opt. Soc. Am. Entry 
Vol. 60, No. 11, pp. 1495-1500 YOB 

J. Phys. Soc. Japan Entry 
Vol. 29, No. 2, pp. 449-458 N05 

J. Quant. Spectrosc. Radiat Transfer Entry 

Vol. 10, No. 12, pp. 1291-1300 Y13 

Vol. 10, No. 12, pp. 1347-1348 CIS 

J. Spacecraft Rockets Entry 

Vol. 7, No. 11, pp. 1317-1322 S46 

Mater. Res. Stan. Entry 
Vol. 10, No. 12, pp. 16-33 M44 

Navigation Entry 
Vol. 17, No. 3, pp. 219-225 DIO 



313 



Phys. Fluids Entry 
Vol. 13, No. 11, pp. 2696-2709 B20 

Science Entry 
Vol. 170, No. 3962, pp. 1092-1094 J04 

Sof. Phys. Entry 

Vol. 14, No. 2, pp. 440-456 S45 

Vol. 15, No. 1, pp. 97-101 YIO 



NASA - JPl - Coml., L.A., Calif. 



314