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SATURN I BLOCK I I GUIDANCE SUMMARY REPORT
B y R . A . CHAPMAN Aero-Astrodynamics Laboratory
NASA
George C. Marsball Space Flight Center,
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TECHN I CAL MEMORANDUM X- 53398
SATURN I BLOCK I I GUIDANCE SUMMARY REPORT
BY
R. A. Chapman
George C. Marshal l Space F l i g h t Center
Hun tsv i l le,Alabama
e ABSTRACT
One of t h e miss ions assigned t o t h e Saturn I Block I I v e h i c l e s was f l i g h t t e s t i n g t h e ST-124 i n e r t i a l guidance system. a n a l y t i c r e p o r t o f t h e ST-124 p la t fo rms and associated hardware f lown on t h e s i x Saturn I Block I I vehic les, SA-5 through SA-IO.
T h i s i s an
Th is r e p o r t presents f o r each v e h i c l e t h e v e l o c i t y component e r r o r s versus t ime f o r t h e t o t a l powered f l i g h t , combinations o f p l a t f o r m system e r r o r s t h a t would produce t h e v e l o c i t y e r r o r p r o f i l e s , and t h e v e l o c i t y component e r r o r corresponding t o each p l a t f o r m system e r r o r .
NASA - GEORGE C. MARSHALL SPACE FLIGHT CENTER
,
NASA - GEORGE C, MARSHALL SPACE FL IGHT CENTER
TECHNICAL MEMORANDUM x-53398
February 23, 1966
SATURN I BLOCK I I GUIDANCE SUMMARY REPORT
BY
R. A. Chapman
AERO-ASTRODYNAMICS LABORATORY
RESEARCH AND DEVELOPMENT OPERATIONS
)I TABLE OF CONTENTS
Page
I .O INTRODUCTION ............................................ 2
2.0 SATURN I BLOCK I I GUIDANCE SYSTEMS h ...................... 1-3
3.0 DESCRl PT lON OF THE ST-I 24 PLATFORM SYSTEM a.. ............. 5
4.0 ERROR ANALYSES (6 .......................................... 5 - 7
4.1 GUIDANCE VELOCITY COMPARISONS ( ........................... 8 , 17 h 4.2
4.3
ST-124 PLATFORM SYSTEM ERRORS (a .......................... 17-20, 29
CORRELAT ION BETWEEN GU I DANCE ERRORS (6. .................... 29
5.0 CONCLUSIONS w............................................. 29-30
iii
(U) L IST OF ILLUSTRATION%
Figure
3- I
4- I
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-1 I
4-12
5- I
5-2
5-3
5-4
T,i t I e Page
ST-124 Pla t fo rm Schematic......,......,.......... 4
I n e r t i a l V e l o c i t y Comparisons SA-5 * #
11 (Telemetered,minus Tracking) ................... 12
Iner t ia4 V e l o c i t y Comparisons SA-6 (Telemetered minus Track ing) ...................
rr' I n e r t i a l V e l o c i t y C par isons SA-7
I n e r t i a I Ve I oc i t y m a p a r i sons SA-9
i? 13
14
(Telemetered minu Tracking) ...................
(Telemetered. minus Track ing) ................... 1
I n e r t i a l V e l o c i t y Comparisons SA-8 (Telemetered minus Tracking). . . .. . .&:. . . . . . . . . 15
I n e r t i a l V e l o c i t y Comparisons S A - I O 16 (Telemetered minus Tracking) ..................
Guidance Hardware E r r o r C o n t r i b u t i o n (SA-5)..... 22
Guidance Hardware E r r o r C o n t r i b u t i o n (SA-6)..... 23
Guidance Hardware Error C o n t r i b u t i o n (SA-7)..... 24
Guidance Hardware Error C o n t r i b u t i o n (SA-9)..... 25
Guidance Hardware E r r o r C o n t r i b u t i o n (SA-8)..... 26
Guidance Hardware Error C o n t r i b u t i o n (SA-IO) . . . . 27
Guidance Accelerometer and I n i t i a l Alignment 32 Errors..............,,.....,.........,........
33 Gyro D r i f t Rates.,.......,......................
Guidance Error Comparisons (Ana lys is minus 34 Predicted)....................................
35 Guidance Error Comparisons (Ana lys is minus
Predicted)....................................
iv
Tab I e
2- I
4- I
4-1 I
4-1 I I
4-IV
5- I
(U) L I S T OF TABLES
T i t l e Page
Saturn I Block I1 P l a t f o r m Systems .........,..... 3
I n e r t i a l V e l o c i t y Comparisons .................... 9
Space-Fixed V e l o c i t y Comparisons a t O r b i t a l Insertion...............................,...... 10
ST-124 P l a t f o r m System Errors.,.................. 21
C o r r e l a t i o n Coefficients......................... 28
Guidance Error Comparisons.......... ..,.......... 31
V
Symbo I
B
M P9
X,Y S
(U) DEFINITION OF SYMBOLS
Definition i Acceleration bias
Misalignment of the sensitive axis of the pth - accelerometer about the qth - axis. Initial platform leveling error In yaw
Initial azimuth error
Initial platform leveling error In pitch
Constant drift rate of X,Y,Z gyros re pectlvely. 3 I 1 11- g sensitive drift due to mass unbalance along the spin reference axis (X and Y gyros respectively).
Drift due to end plate "g"-sensItive turbine torque (X,Y,Z gyros respectively).
11 11- g sensitive drift due to mass unbalance along input axis of Z gyro
Schle factor error of range and altitude accelerometers respectively.
Refers to ith row
Refers to j t h column
'vi
TECHN I CAL MEMORANDUM X- 53i98
SATURN I BLOCK I I GUIDANCE SUMMARY REPORT
SUMMARY
Th is r e p o r t presents an e r r o r ana lys is of t h e ST-124 i n e r t i a l p l a t f o r m systems f lown on t h e Saturn I Block I I f l i g h t s . F ina l data from pre- c i s i o n t r a c k i n g were used f o r comparisons w i t h t h e telemetered guidance v e l o c i t i e s . These d i f f e r e n c e s were input t o a weighted Least Squares Program t o determine t h e most probable sets of p l a t f o r m system er ro rs . The e r r o r s o l u t i o n s were v e r i f i e d by a d j u s t i n g t h e telemetered v e l o c i t i e s and computing a continuous t r a j e c t o r y comparable t o t h e reference t r a j e c t o r y and s a t i s f y i n g t h e o r b i t a l i n s e r t i o n condi t ions.
Although some p l a t f o r m system e r r o r s were l a r g e r than des i red for a p r e c i s i o n f l i g h t , averages f o r t h e s i x Saturn I Block I I f l i g h t s ind ica ted o n l y t h e "g"-sensi t ive gyro d r i f t s were grea ter than t h e 3a value s p e c i f i - cat ions. 0.05 deg/hr/g. However, s ix teen o f twenty-four "g"-sensi t ive d r i f t terms were pred ic ted grea ter than t h e e r r o r ana lys is ind icated.
The average e r r o r was 0.07 deg/hr/g compared t o a 3a value of
The f l i g h t t e s t s ind ica ted each guidance system performed t o a h igh degree o f accuracy.
J), I .O INTRODUCTION
One o f the missions assigned t o t h e Saturn I Block I I veh ic les was f l i g h t t e s t i n g t h e ST-124 i n e r t i a l guidance system. r e p o r t o f the ST-124 s t a b l e p la t fo rms and associated hardware f lown on s i x Saturn I Block I I vehic les, Saturn SA-5 through SA- IO .
Th is i s an a n a l y t i c
The analyses presented i n t h i s repor 4 are based on comparisons o f t h e telemetered guidance data w i t h f i n a l t r a c k i n g i n c l u d i n g establ ished o r b i t a l i n s e r t i o n condi t ions. F ina l t r a c k i n g f o r most f l i g h t s was not received i n t ime t o be used f o r t h e "Test F l i g h t Resul ts" analyses; therefore, intermediate t r a c k i n g data were used t o i s o l a t e any s i g n i f i - can t guidance system e r r o r g rea ter than p r e d i c t i o n s based on laboratory t e s t s o f t h e hardware.
The general phi losophy fo l lowed f o r t h e eva lua t ion r e p o r t s was t o assume t h e e r r o r p r e d i c t i o n s were known e r r o r terms and then so lve f o r a minimum o f a d d i t i o n a l values requi red t o approximate t h e v e l o c i t y e r r o r p ro ' f i l es . For t h i s repor t , t h e e r r o r p r e d i c t i o n s were used as "a p r i o r i " est imates and a more complete guidance e r r o r model was used w i t h t h e best t r a c k i n g data a v a i l a b l e f o r each v e h i c l e f l i g h t . Although t h e f i n a l r e s u l t s are very s i m i l a r , they are no t necessar i ly i d e n t i c a l t o those shown i n reports, "Results of t h e Saturn I Launch Vehic le Test F l i g h t " , publ ished soon a f t e r each v e h i c l e f l i g h t . (See References)
This repor t presents f o r each veh ic le t h e v e l o c i t y component e r r o r s versus t ime f o r t h e t o t a l powered f l i g h t , combinations o f p l a t f o r m system e r r o r s t h a t would produce t h e v e l o c i t y e r r o r p r o f i l e s , and t h e v e l o c i t y component e r r o r corresponding t o each p l a t f o r m system e r r o r .
(U) 2.0 SATURN I BLOCK I I GUIDANCE SYSTEMS
The p la t fo rm systems f lown on t h e Saturn I Block I I veh ic les and t h e func t ion o f each system are shown i n Table 2-1.
Although two previous vehic les, SA-3 and SA-4, c a r r i e d prototypes of t h e ST-124 plat form, Saturn SA-5 was t h e f i r s t v e h i c l e t o c a r r y t h e com- p l e t e ST-124 guidance system. I n e r t i a l v e l o c i t i e s and v e h i c l e a t t i t u d e s referenced t o t h e ST-124 p l a t f o r m were fed i n t o an ASC-15 guidance com- pu ter for computations o f "Path Adaptive" guidance commands and t o i n i t i a t e d i s c r e e t s ignals. The guidance was i n open loop.
An ST-90-S p l a t f o r m system was a l s o c a r r i e d on t h e SA-5 v e h i c l e and used as a reference f o r a t t i t u d e c o n t r o l . The ST-90-S p l a t f o r m was a mod i f i ca t ion o f t h e ST-90 system f lown on t h e J u p i t e r f l i g h t s . The mod- i f i c a t i o n consisted o f an extended azimuth d r i v e t o permi t a programmed r o l l maneuver t o t u r n t h e v e h i c l e from a 90 degree launch azimuth t o t h e desired f l i g h t azimuth.
2
Saturn SA-6 a l s o c a r r i e d two p l a t f o r m systems. The ST-90-S system generated s i g n a l s t o t u r n t h e veh ic le i n t o t h e des i red f l i g h t azimuth and served as a reference for a t t i t u d e c o n t r o l o f t h e S - l stage. A t about 14 sec a f t e r S - I / S - I V separat ion, a t t i t u d e e r r o r s igna ls were switched from t h e ST-90-S t o t h e ST-124 p la t form. t h e guidance loop was closed and t h e v e h i c l e f l e w a guided t r a j e c t o r y , "Path Adaptive" i n t h e p i t c h plane and "Delta Minimum" i n t h e yaw plane, referenced t o t h e ST-124 p la t fo rm system.
A t about 168 sec of f l i g h t ,
Vehic le
SA-5
Saturn SA-7 and subsequent Saturn I Block I t veh ic les c a r r l e d o n l y t h e ST-124 p l a t f o r m systems which generated s i g n a l s t o t u r n t h e veh ic les i n t o t h e des i red f l i g h t azimuth and served as reference f o r a t t l t u d e con- t r o l o f t h e s- l stages. The guidance loop was closed i n t h e S - I V stage of each veh i c I e. SA-7 u t I I i zed the "Path Adapt 1 vel' and "De I t a 'M i n i mum" guidance mode for p i t c h and yaw, respec t ive ly . SA-9, SA-8, and S A - I O veh ic les u t i 1 ized t h e " I t e r a t i v e " guidance mode ( IGM) and "Delta Minimum" for p i t c h and yaw, respec t ive ly .
P la t fo rm System Funct i on
ST-90-S I n i t i a l r o l l maneuver and a t t i t u d e c o n t r o l
ST- I 24 Passenger
reference e n t i r e powered f I i g h t
The S - I V stage of each of t h e guided Saturn 1 Block I I veh ic les was guided t o s a t i s f a c t o r y o r b i t a l i n s e r t l o n cond i t ions .
ST-90-S
ST- I24
TABLE 2-1 8 SATURN I BLOCK I I PLATFORM SYSTEMS
I n i t i a l r o l l maneuver and a t t i t u d e c o n t r o l reference S-l stage A t t i t u d e c o n t r o l and closed loop "Path Adaptive" guidance reference S - I V stage
SA-8
SA-6
S i - I24 A t t i t u d e c o n t r o l and closed loop " I t e r a t i v e " guidance reference e n t i r e powered f I i g h t
SA-7
ST- I24 I SA- I O A t t i t u d e c o n t r o l and closed loop " I t e r a t i v e " guidance reference e n t i r e powered f l i g h t
ST- I24 A t t i t u d e c o n t r o l and closed loop "Path Adaptive" guldance reference e n t i r e powered f l i g h t
SA-9 ST- I24 I A t t i t u d e c o n t r o l and closed loop " I t e r a t i v e " guidance reference e n t i r e powered f l i g h t i
I 1 1
3
\ \ \
I
4
0 ) 3.0 DESCRIPTION OF THE ST-124 PLATFORM SYSTEM
The ST-124 p la t fo rm i s a four-gimbal system which permi ts f u l l f ree- dom about a l l t h r e e v e h i c l e axes. The gimbal o rde r from t h e veh ic le t o t h e inner gimbal i s p i t c h redundant, yaw, p i t c h l i m i t e d , and r o l l . The p i t c h redundant gimbal i s pos i t ioned from a p i t c h command reso lver and a gimbal reso lve r opera t ing i n t o an associated gimbal servo. The p i t c h l i m i t e d gimbal i s c o n t r o l l e d t o e s s e n t i a l l y zero (steady s t a t e ) .
Three pendulous i n t e g r a t i n g gyro accelerometers (AMAB-3-K4) are mounted on t h e ST-124 s t a b i l i z e d element. The range and cross range accelerometers a re normal t o each o the r i n t h e loca l hor izon ta l p lane a t launch w i t h t h e range accelerometer d i rec ted down range. Cross range ou tpu t i s p o s i t i v e r i g h t w i t h observer f a c i n g down range. The a l t i t u d e accelerometer i s d i rec ted up and normal t o t h e launch hor izon ta l plane.
The ST-124 p l a t f o r m i s s t a b i l i z e d by t h r e e (AB-5-K3-P) a i r bearing, single-degree-of-freedom gyros mounted w i t h t h e s e n s i t i v e axes mutua l l y perpendicular. The gyro axes ( s e n s i t i v e o r input, output, sp in re ference) a re o r ien ted such t h a t some of the "g"-sensi t ive d r i f t s and a l l t h e "g2"-sensi t ive d r i f t s a re e f f e c t i v e l y zero or , i n any case, a minimum. A schematic of t h e ST-124 p la t fo rm system i s shown i n F igure 3-1.
4.0 ERROR ANALYSES
The e r r o r analyses o f t h e ST-124 guidance p l a t f o r m system are based on comparisons of t h e te lemetered guidance v e l o c i t i e s w i t h f i n a l t r a c k i n g data f o r each veh ic le . Although the r e s u l t s a re very s i m i l a r , they are n o t necessar i l y i d e n t i c a l t o those presented i n "Test F l i g h t Resul ts" publ ished soon a f t e r each veh ic le f l i g h t (see References).
The guidance e r r o r model used f o r t h e analyses has been s i m p l i f i e d by combining e r r o r terms t h a t produce l i k e v e l o c i t y e r r o r p r o f i l e s and e l i m i n a t i n g e r r o r terms t h a t a re genera l l y considered n e g l i g i b l e . Because o f t h e alignment of t h e p la t fo rm a t launch w i t h respect t o t h e plane conta in- i n g t h e t h r u s t vector, some of the d r i f t s caused by mass unbalance and a l l o f t h e a n i s o e l a s t i c d r i f t s are n e g l i g i b l e .
The p l a t f o r m i s leve led i n the h o r i z o n t a l p lane a t launch w i t h t h e c ross range accelerometer e l e c t r o n i c a l l y a l igned i n azimuth. Since t h e c ross range acce le ra t i on i s e s s e n t i a l l y zero dur ing f l i gh t , an e r r o r com- ponent picked up by e i t h e r t h e range or a l t i t u d e accelerometers r o t a t e d i n t o cross range would be n e g l i g i b l e f o r small angle r o t a t i o n s . Thus, t h e a l t i t u d e accelerometer e r r o r i n t h e p i t c h p lane u s u a l l y i s t h e o n l y nonor thogonal i ty e r r o r considered. A t o t a l of eighteen p la t fo rm system e r r o r terms has been considered i n t h e analyses. The e r r o r term con- s idered are:
5
a. b.
C.
d. e.
f .
h.
. :* I '
Bias e r r o r f o r each o f t h e t h r e e accelerometers. Scale f a c t o r e r r o r f o r range and a l t i t u d e accelerometers. Scale f a c t o r e r r o r f o r cross range i s n e g l i g i b l e . Nonorthogonal i ty o f . a I t i t u d e accelerometer i n t h e p i t c h plane. I n i t i a l p l a t f o r m al ignment e r r o r s i n p i t c h , yaw,and azimuth. Constant d r i f t o f t h e p l a t f o r m about t h e input axes of +he th ree s t a b i l i z i n g gyros.
reference axes o f t h e yaw ( X I and r o l l ( Y ) gyros. "g" -sens i t i ve d r i f t due t o mass unbalance along t h e input a x i s of t h e p i t c h ( Z ) gyro. End p l a t e "g"-sensi t ive t u r b i n e torque f o r each of t h e t h r e e s tab i I i z i n g gyros.
11 11- g s e n s i t i v e d r i f t due t o mass unbalance along t h e s p i n
The guidance p l a t f o r m e r r o r model i s described by t h e f o l l o w i n g equat ion : - - - -
Ai = B t S Xm [Mpq] [SI Xm
where B = accelerometer b ias e r r o r .
S = accelerometer scale f a c t o r e r r o r . c
Subscr ipt m = denotes an ideal measuring system.
[M ] P9
= 3 X 3 m a t r i x d e f i n i n g t h e misal ignment o f t h e s e n s i t i v e a x i s o f t h e p t h accelerometer about t h e q t h ax is .
[SI = 3 X 3 m a t r i x d e f i n i n g t h e instantaneous al ignment o f the p l a t f o r m w i t h respect t o t h e ideal al ignment. Th is includes t h e e f f e c t s o f a l l d r i f t terms.
Measurements made by t h e guidance accelerometers are referenced t o a p o i n t i n i n e r t i a l space. Th is p o i n t co inc ides w i t h t h e launch s i t e a t t ime of "Guidance Release" which occurs a t o r j u s t p r i o r t o l i f t o f f of t h e vehic le . are mounted remains f i x e d i n i n e r t i a l space throughout f l i g h t . Er ro rs made i n the v e l o c i t y measurements r e s u l t from imperfect accelerometers and nonideal al ignment o f t h e s t a b l e p l a t f o r m a t any t ime a f t e r guidance release. present dur ing a veh ic le f l i g h t , t h e measured v e l o c i t i e s a re referenced against a set o f data t h a t descr ibes t h e t r a j e c t o r y of t h e p a r t i c u l a r f l i g h t .
Idea l l y , t h e s t a b i l i z e d p l a t f o r m on which t h e accelerometers
In o rder t o determine t h e p l a t f o r m system e r r o r s t h a t were
6
The reference data used i n these analyses vary from f l i g h t t o f l i g h t according t o t h e a v a i l a b i l i t y of p r e c i s i o n t r a c k i n g data. case t h e establ ished i n s e r t i o n cond i t ions were considered t o be more accurate than data from any i n d i v i d u a l t r a c k i n g system.
I n each
Tracking data, inc lud ing establ ished i n s e r t i o n points , a re converted t o t h e guidance coord inate system and compared w i t h t h e guidance accelero- meter outputs (guidance minus t r a c k i n g ) t o e s t a b l i s h t h e v e h i c l e e r r o r p r o f i l e s . ing system, o n l y random noise i s considered i n t h e covariance m a t r i x used i n t h e guidance e r r o r ana lys is . The t r a c k i n g data have been processed t o e l iminate, t o some extent , known e r r o r s before comparisons are made w i t h guidance.
Although t r a c k i n g data conta in e r r o r s p e c u l i a r t o each t r a c k -
The guidance v e l o c i t y e r r o r model i s f i t t e d t o t h e v e l o c i t y e r r o r pro- f i l e s by a double p r e c i s i o n weighted "Least Squares" method t o determine a s e t o f guidance system e r r o r s t h a t would produce t h e ' v e l o c i t y devia- t i o n s ( r e s i d u a l s ) between t h e measured guidance data and t r a c k i n g .
The general equat ion for t h e "Least Squares" s o l u t i o n i s
- U = cw, + PTWP1" Cw-u, t PTW R-J -
where U
P
Superscr ip t T
Superscr i p t - I
W
w 0
- !?
0 U
v v
p l a t f o r m system e r r o r s ( n x I )
3 X n m a t r i x of p a r t i a l d e r i v a t t v e s r e l a t i n g t h e v e l o c i t y e r r o r t o t h e p l a t f o r m system e r r o r s , denoted m a t r i x transpose.
denotes m a t r i x inverse.
3 x res
n X P ia
3 x
3 covariance matr duals.
x associated w i t h t h e
n covariance rna t r x associated w i t h t h e form system e r r o r terms.
! m a t r i x c f residuals !Gulbance iii:niis Tracking).
n X I m a t r i x of ''a p r i o r i " est imates of t h e p la t fo rm system e r r o r terms.
7
4.1 GUIDANCE VELOCITY COMPAR SONS
The reference data used f o r guidance compar sons v a r i e d between f l i g h t s . For t h e f i r s t t h r e e Saturn I Block I I (SA-5, SA-6, SA-7) f l i g h t s no t r a c k i n g system adequately covered t h e major p o r t i o n of t h e f l i g h t . Therefore, f i n a l p o s t f l i g h t t r a j e c t o r i e s , based on var ious t r a c k i n g and i n s e r t i o n data, were used f o r e s t a b l i s h l n g t h e guidance v e l o c i t y e r r o r p r o f i l e s . MISTRAM, t i e d t o c lose- in t r a c k i n g from Cape Kennedy, and i n s e r t i o n data were used as reference data f o r veh ic les SA-9 and SA-8. The ana lys is for S A - I O was based on ODOP t r a c k i n g and i n s e r t i o n data. The q u a l i t y o f t h e t r a c k i n g from t h e i n d i v i d u a l systems used f o r SA-9, SA-8, and S A - I O was v e r i f i e d by a d j u s t i n g t h e measured guidance v e l o c i t i e s f o r e r r o r s corresponding t o t h e analyses made and computing t r a j e c t o r i e s t h a t s a t i s f i e d cond i t ions establ ished f o r o r b i t a l i n s e r t i o n of each vehic le . The v e l o c i t y c o n d i t i o n s were completely s a t i s f i e d and p o s i t i o n d i f f e r e n c e s were w i t h i n t h e accuracies associated w i t h t h e i n s e r t i o n data.
The comparisons o f t h e v e l o c i t y components a r e shown, p l o t t e d versus range time, i n Figures 4-1 through 4-6. The s o l i d l i n e s represent t h e comparisons between guidance v e l o c i t i e s and range t r a c k i n g or ( fo r v e h i c l e SA-5, SA-6, SA-7) f i n a l p o s t f l i g h t t r a j e c t o r y . The c i r c l e d p o i n t s represent v e l o c i t y d i f f e r e n c e s associated w i t h t h e guidance system e r r o r s determined from t h e analyses. The comparisons d i t h establ ished i n s e r t i o n v e l o c i t i e s are shown enclosed i n squares.
The i n e r t i a l v e l o c i t y components and t o t a l v e l o c i t i e s a t c u t o f f o f t h e S - l stage and o r b i t a l i n s e r t i o n are shown f o r each v e h i c l e i n Table 4-1. Predicted, t r a c k i n g , and telemetered values are shown f o r com- par ison. Since t h e Saturn veh ic les a r e no t const ra ined t o a predeter- mined powered t r a j e c t o r y and t h e programmed S - I V c u t o f f v e l o c i t y i s i n a space-f ixed ( inc ludes t h e e f f e c t o f g r a v i t y ) p lumbl ine coord inate systems, the telemetered i n e r t i a l v e l o c i t i e s a re not.necessar i1y c lose t o predic ted values. The v e l o c i t y d i f f e r e n c e s r e f l e c t t h e nonstandard performance of t h e t o t a l v e h i c l e system i n a d d i t i o n t o any guidance e r r o r s .
The v e l o c i t y d i f f e r e n c e s between te lemetry and t r a c k i n g r e f l e c t t h e e r r o r s o f t h e guidance system. Although t r a c k i n g does conta in e r ro rs , t h e values i n Table 4-1 should be v a l i d e s p e c i a l l y a t o r b i t a l i n s e r t i o n .
The i n e r t i a l v e l o c i t y outputs o f t h e guidance accelerometers were converted t o space-f ixed values by t h e onboard (ASC-15) guidance computer for use i n path guidance computations. Table 4-11 shows t h e space-fixed v e l o c i t i e s telemetered from t h e guidance computer compared w i t h pre- ca lcu la ted and o r b i t a l t r a c k i n g a t t ime o f o r b i t a l i n s e r t i o n . Since SA-5 was f lown w i t h open loop guidance, t h i s v e h i c l e was n o t included.
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The preca lcu la ted v e l o c i t y vecl;or.at S - I V c u t o f f was presef i n t h e guidance computer and cu to f f s i g n a l "&s"#&&4iitwhen t h e onboard measure- ment equaled t h e preset value. O r b i t a l i n s e r t i o n occurred I O sec a f t e r S-IV c u t o f f . For SA-6 t h e precalcu lated v e l o c i t y vec tor a t i n s e r t i o n was erroneously p rese t i n t h e guidance computer as c u t o f f v e l o c i t y which exp la ins most of t h e 6.2 m/s v e l o c i t y d i f f e r e n c e a t i n s e r t i o n . veh ic les SA-6 and SA-7 t h e t ime delay between c u t o f f s ignal and actual c u t o f f was n o t included i n computations o f v e l o c i t y increase due t o t h r u s t decay. t h e te iemetered and precalcu lated v e l o c i t y vectors was w i t h i n - +O,I m/s a t o r b i t a I i n s e r t ion.
For
This was included for subsequent veh ic les and t h e d e v i a t i o n between
The d i f f e r e n c e s between t h e telemetered guidance values and o r b i t a l t r a c k i n g r e f l e c t t h e e r r o r s of t h e guidance system and e r r o r s i n t h e g r a v i t y p r o f i l e s based on t h e measured guidance v e l o c i t i e s .
4.2 ST-124 PLATFORM SYSTEM ERRORS
The phi losophy fo l lowed f o r the f i n a l analyses was t h a t t h e most probable s e t of guidance e r r o r s would represent adjustments t o t h e te lemetered v e l o c i t i e s necessary t o s imulate t h e v e h i c l e t r a j e c t o r y w i t h specia l emphasis on t h e o r b i t a l i n s e r t i o n condi t ions. D i f f e r e n t ph i losophies concerning confidence i n p r e f l i g h t est imates and pred ic ted performance can vary so lu t ions using t h e same data and method. may be v e r i f i e d by comparing e r r o r s o l u t i o n s shown i n Table 4-111. E s s e n t i a l l y , t h e same method, weighted "Least Squares", was used f o r t h e p o s t f l i g h t eva lua t ion r e p o r t s ( 1 ) as was used for t h e f i n a l analys is . The f i n a l t r a c k i n g data was a l s o a v a i l a b l e f o r SA-8 and S A - I O veh ic les before t h e p o s t f l i g h t eva lua t ion r e p o r t s were published. i n these repor ts , t h e p r e f l i g h t est imates were considered genera l l y accurate and weighted accordingly. A minimum amount of f l e x i b i l i t y was permi t ted t o g i v e a s o l u t i o n t h a t would f it t h e end p o i n t and g iven an e r r o r p r o f i l e s i m i l a r t o the observed v e l o c i t y d i f ferences. The s o l u t i o n s were constrained t o the p r e f l i g h t est imates w i t h i n the data noise leve l p e r m i t t i n g a minimum o f terms t o exceed t h e p r e f l i g h t est imates.
Th is
For the analyses used
The procedure used f o r t h e f i n a l analyses a l s o u t i l i z e s a weighted "Least Squares" approach. terms were used as 'la p r i o r i " est imates for a f i r s t pass a t f i t t i n g t h e
heavier than +3u l i m i t s were t h e angular e r r o r s made i n mounting t h e accelerometer? on t h e p la t fo rm (general l y 0. I t imes 3a values). are r e f e r r e d t o as nonorthogonal i ty o f t h e i n d i v i d u a l accelerometer s e n s i t i v e a x i s w i t h respect t o another accelerometer. Constra in ts were placed on t h e s o l u t i o n t o insure a curve f i t o f t h e res idua ls t o f a l l w i t h i n t h e noise leve l of t h e data used. Completely w i l d d a t a o r data gaps were weighted o u t of t h e so lu t ion . O r b i t a l i n s e r t i o n data were h e a v i l y weighted.
However, p r e f I i g h t est imates o f t h e e r r o r
established velocity 8rrOr p r o f i l e s . The m l y p r e f l i g h t BTTOTS weigh+ed
These
( I ) Reports publ ished by F l i g h t Evaluat ion Group (See References).
17
Successive cases were computed, i t e r a t i n g around t h e previous case t o e l i m i n a t e unnecessary compensating e r r o r terms, u n t i l a s e t of guidance e r r o r terms was der ived w i t h a minimum number exceeding t h e magnitude o f t h e "a p r i o r i " est imates and 'ye t f i t t h e observed v e l o c i t y e r r o r curves. The s o l u t i o n s were v e r i f i e d as reasonable by a d j u s t i n g t h e measured guidance v e l o c i t i e s by t h e e r r o r s o l u t i o n s and computing t r a j e c t o r i e s t h a t compared very favorably w i t h t h e p o s t f l i g h t t r a j e c t o r i e s and s a t i s f i e d t h e i n s e r t i o n v e l o c i t y components w i t h i n +0.1 m/s and p o s i t ions t o w i t h i n t h e accuracies quoted for t h e 1 nserFion parameter so lu t ions .
Table 4-111 presents t h e f i n a l p l a t f o r m system e r r o r s o l u t i o n s f o r each o f t h e Saturn I Block I I vehic les. A lso shown for each v e h i c l e a r e t h e p r e f l i g h t est imates o f t h e e r r o r s and t h e values presented I n t h e i n d i v i d u a l eva lua t ion repor ts . The e r r o r s a re l i s t e d under seven major types. Three types of e r ro rs , b ias, sca le f a c t o r , and nonorthogonal i ty, p e r t a i n t o the accelerometers. Two types, p l a t f o r m l e v e l i n g i n p i t c h and yaw and azimir-bh alignment, p e r t a i n t o t h e o r i e n t a t i o n of t h e measuring d i r e c t i o n s a t launch. Two types o f d r i f t , constant and "g"-sensi t ive. p e r t a i n t o the s t a b i l i z i n g gyros. are known t o e x i s t , they are e i t h e r i n s i g n i f i c a n t or cannot be d is t ingu ished from some one of t h e l i s t e d terms.
Although e r r o r s o t h e r than those l i s t e d
Since the acce le ra t ion i n t h e cross range d i r e c t i o n i s very small or e s s e n t i a l l y zero for t h e major p o r t i o n of powered f l i g h t , t h e scale f a c t o r e r r o r s of t h e cross range accelerometer and t h e nonor thogonal i ty of t h e range and a l t i t u d e s e n s i t i v e axes w i t h respect t o t h e cross range d i r e c t i o n were assumed t o be as predic ted. Any p o s t f l i g h t solu- t i o n f o r these e r r o r s would be h i g h l y quest ionable. one "g"-sensi t ive d r i f t term f o r each gyro and a l l a n i s o e l a s t i c d r i f t s were n o t considered.
For t h e same reason
The f i n a l p o s t f l i g h t analyses ind ica ted t h e accelerometer b i a s e r r o r s were genera l l y c lose t o t h e p r e f l i g h t est imate, accelerometers f o r each o f s i x veh ic les) four teen were equal i n s i g n or e s s e n t i a l l y zero. Only two accelerometers, range and a l t i t u d e for SA-5 and S A - I O respec t ive ly , experienced b i a s e r r o r s s i g n i f i c a n t l y g r e a t e r than t h e 3a value o f 0.5 X 10-3 m/sec2.
O f e ighteen values ( t h r e e
The scale f a c t o r e r r o r s were e s s e n t i a l l y as p red ic ted except for SA-9. The p o s t f l i g h t so lu t ions showed four values of d i f f e r e n t s igns b u t e s s e n t i a l l y t h e same magnitude as predic ted. t o i n t e r p r e t a t i o n of t e s t data. The scale f a c t o r e r r o r s shown for SA-9 could be due t o approximately 4 degree lower than normal gimbal temper- a t u r e t h a t was experience est imates were assumed f o r t h e cross range acceler
Th is discrepancy could very we l l be due
18
The p l a t f o r m i s o r i e n t e d so t h a t t h e sensi-hye axes of t h e range and cross range accelerometers are i n the hor izon ta l &ane w i t h t h e cross range a x i s more accurate ly a l igned. and azimuth e r r o r s leav ing t h e nonorthogonal i ty o f t h e a l t i t u d e accelero- meter w i t h respect t o range d,i-rect ion t h e o n l y e f f e c t i v e e r r o r i n mount- ing t h e accelerometers. Although the p o s t f l i g h t s o l u t i o n s ind ica ted t h e p r e f l i g h t measurements were h i g h l y accurate ( l e s s than 2 sec of a rc except for SA-6 which was o n l y 6.8 a r c sec.), t h e accelerometer mounting was r a t h e r poor f o r SA-5 and SA-6. SA-7 was much more accurate ly assembled, bu t subsequent veh ic les show t h a t the accelerometers can be mounted t o a h igh degree o f p rec is ion .
Th is procedure minimizes t h e range
The r a t h e r la rge l e v e l i n g and azimuth e r r o r s noted on t h e f i r s t t h r e e Saturn I Block I I veh ic les were e v i d e n t l y due t o v i b r a t i o n s dur ing t h r u s t bu i ldup. l i f t o f f s igna l . When t h e p la t fo rm became space-f ixed a t l i f t o f f , t h e p o s i t i o n of t h e p l a t f o r m became t h e gyro n u l l p o s i t i o n . s t a b i l i z e d t h e p l a t f o r m t o t h e l i f t o f f p o s i t i o n . Beginning w i t h SA-9, t h e p l a t f o r m was space-fiwed p r i o r to i g n i t i o n and t h e i n i t i a l e r r o r s were reduced t o less than 3a values i n each case except for p i t c h l e v h l i n g on S A - I O which was o n l y 0.007 deg compared t o t h e 3a value of 0.005 deg. Leve l ing and azimuth p r e f l i g h t est imates shown are 3a values.
The p l a t f o r m was torqued t o compensate for e a r t h ' s r o t a t i o n u n t i l
The gyros
With one except ion t h e d i r e c t i o n s assigned t o t h e p r e f l i g h t est imates of t h e guidance e r r o r terms shown i n Table 4-111 were taken fr m memoranda publ ished p r i o r t o launch o f each vehic le . I n these memoranda nonorthogona- I i t y was def ined as p o s i t i v e when the angle between t h e measur ng d i r e c t i o n s of two accelerometers was grea ter than 90 degrees. I n t h e ana y s i s program t h e o r t h o g o n a l i t y e r r o r i s considered as an angular ro a t i o n o f t h e measuring d i r e c t i o n about an a x i s and p o s i t i v e f o r a r i g h t hand r o t a - t ion.
A p o s i t i v e b ias o t scale f a c t o r e r r o r ind ica tes an accelerometer o u t - pu t g r e a t e r than t h e absolute value. gyro d r i f t e r r o r permi ts t h e p l a t f o r m t o move i n a r ight-handed sense about t h e ideal axes and t h e veh ic le f o l l o w s t h e p la t form.
A p o s i t i v e p l a t f o r m al ignment o r
The p r e d i c t i o n s o f t h e magnitude o f t h e constant gyro d r i f t terms were r e l a t i v e l y cons is ten t w i t h t h e p o s t f l i g h t r e s u l t s . terms iii and Y g y m s f ~ r SA-5 and Y gyro f o r SA-6)were s i g n i f i c a n t l y g r e a t e r than pred ic ted and one of t h e th ree ( X gyro SA-5) was e s s e n t i a l l y a 3a value o f 0.075 deg/hr.
Only t h r e e
Gyro d r i f t s r e f e r r e d t o as "g"-sensi t ive d r i f t s a re due t o mass un- balance along t h e input and spin-reference axes and end p l a t e misa l ign- ment producing a torque propor t iona l t o acce le ra t ion p a r a l l e l t o t h e ou t - pu t ax is . Since e i t h e r t h e input o r spin-reference a x i s i s i n t h e cross range d i r e c t i o n for each gyro, were considered. No p d r i f t s on veh ic les SA-5 and
i t i v e terms f o r each ions were pub1 ished for t h e "g"-sens t i v e
19
Several t e s t s are made i n t h e aboratory t o approxlmate t h e "g"- s e n s i t i v e gyro d r i f t s . t h e p r e f l i g h t est imate. accurate o f t h e pred ic ted hardware e r r o r s due t o inconsistency (non- r e p e a t a b i l i t y ) of day t o day laboratory measurements. However, t h i s should n o t be in te rpre ted as a r e f l e c t i o n on t h e q u a l i t y o f t h e gyros used w i t h t h e ST-124 p l a t f o r m system. The d r i f t s determined i n t h e laboratory o r from p o s t f l i g h t analyses are probably w i t h i n t h e accuracy o f t h e measurements o f o t h e r types o f gyros t h a t a re less accurate bu t sa id t o be more pred ic tab le .
An average o f these t e s t r e s u l t s i s publ ished as These est imates a r e bel ieved t o be t h e l e a s t
The "g"-sensi t ive d r i f t s determined from t h e p o s t f l i g h t analyses c l o s e l y agreed i n magnitude w i t h p r e d i c t i o n s for eighteen of t h e twenty- f o u r terms shown. O f t h e remaining s i x terms t h a t were s i g n i f i c a n t l y d i f f e r e n t i n magnitude, f o u r were much smal ler .
The s i g n i f i c a n c e of t h e computed guidance e r r o r terms shown i n Table 4-111 Is presented i n Figures 4-7 through 4-12. t r i b u t i o n f o r each hardware e r r o r was computed by m u l t i p l i c a t i o n o f t h e respect ive p a r t i a l d e r i v a t i v e s t imes t h e e r r o r so lu t ions . D e l t a v e l o c i t i e s are shown a t outboard engine c u t o f f , 350 sec, and S - I V stage c u t o f f f o r each veh ic le . The t ime o f 350 seconds was chosen f o r con- venience as an approximate midpoint t o g i v e an i n d i c a t i o n o f t h e v e l o c i t y e r r o r bui ldup. Total v e l o c i t y e r r o r s shown f o r each p o i n t correspond t o respect ive p o i n t s on curves presented i n F igure 4-1 through 4-6.
The v e l o c i t y e r r o r con-
Figures 4-7, 4-8, and 4-9 a re o f somewhat special i n t e r e s t . These Figures show t h e e f f e c t s of t h e e r r o r s o l u t i o n s f o r SA-5, SA-6, and SA-7, respec t ive ly , proximate t h e v e l o c i t y e r r o r p r o f i l e , as was done i n t h e Evaluat ion Reports, w i t h o n l y one e r r o r exceeding t h e predic ted values. t i o n from t h e observed v e l o c i t y e r r o r p r o f i l e could be w i t h i n t h e data no ise leve l e s p e c i a l l y f o r p r e l i m i n a r y data. However, it would seem more r e a l i s t i c , when using f i n a l comparison data, t o permi t more f r e e - dome o f e r r o r d i s t r i b u t i o n and f i t t h e establ ished e r r o r p r o f i l e s . The s o l u t i o n s shown i n Table 4-111 for t h e f i n a l analyses would produce t h e observed v e l o c i t y e r r o r p r o f i l e s as shown i n Figures 4-1 through 4-6.
For veh ic les SA-5 and SA-6 it was not d i f f i c u l t t o ap-
Any devia-
F igure 4-9 shows for SA-7 t h e v e l o c i t y e r r o r s associated w i t h t h e hard- ware e r r o r so lu t ion . smal ler than for t h e two previous f l i g h t s . However, t h i s was not t h e case. A l l attempts t o g e t an unbiased p o s t f l i g h t e r r o r s o l u t i o n i n d i c a t - ed r a t h e r large l e v e l i n g and azimuth e r r o r . Eventual ly, these misa l ign- ment e r r o r s were found t o be due t o v i b r a t i o n s dur ing t h r u s t bu i ldup causing t h e p l a t f o r m t o be s t a b i l i z e d a t an erroneous p o s i t i o n a t l i f t o f f s ignal when It became space-f ixed. As a r e s u l t , f o r subsequent veh ic les t h e p l a t f o r m was space-f ixed p r i o r t o i g n i t i o n and any movement due t o v i b r a t i o n s was sensed by t h e s t a b i l i z i n g gyros and corrected.
SA-7 v e l o c i t y e r r o r s were expected t o be much
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(a 4.3 CORRELAT I ON BETWEEN GU I DANCE ERRORS
Table 4-I-V shows a t y p i c a l set o f c o r r e l a t i o n c o e f f i c i e n t s between t h e var ious guidance system er ro rs . The values a r e g iven t o t h e f i r s t decimal and were computed using t h e equation:
= a /a.a 'ij i j I j
where : u represents t h e elements o f t h e covar iance m a t r i x assoc iat - ing v e l o c i t y component e r r o r s t o t h e guidance system e r r o r s .
i r e f e r s t o t h e i t h row and j r e f e r s t o t h e j t h column.
Although .these values may vary between veh ic les and a l s o between computer runs due t o weight ing fac to rs , th ree p a i r s of e r r o r terms a r e c o n s i s t e n t l y h i g h l y ( p 10.75) cor re la ted , ( 1 ) b ias i n X and scale f a c t o r i n X, ( 2 ) con- s t a n t d r i f t of X gyro and "g" d r i f t p ropor t iona l t o X, ( 3 ) constant d r i f t of Z gyro and "g" d r i f t propor t ional t o X.
5.0 CONCLUSIONS . The purpose of a p o s t f l i g h t ana lys is o f t h e guidance system i s t o
establ i s h t h e conf idence I n p re f 1 i g h t e r r o r measurements and p o i n t o u t areas where improvements may be made. The pred ic ted and p o s t f l i g h t ana lys is p la t fo rm system e r r o r s are shown i n bar graph form i n Figures 5-1 and 5-2. The a s t e r i s k s over the p a r t i c u l a r e r r o r s i n d i c a t e t h a t p red ic ted and ana lys is e r r o r s a r e opposi te i n s ign.
P la t fo rm l e v e l i n g and azimuth e r r o r s were pred ic ted t o be w i t h i n 3a t o I erances of 0.005 and 0 ,O I degrees, respect i ve I y . values observed on SA-5, SA-6, and SA-7 a r e bel ieved t o be r e s u l t s o f v i b r a t i o n s dur tng t h r u s t bu i ldup. The p la t forms, which became space- f i x e d a t l i f t o f f s igna l , probably had moved due t o v i b r a t i o n s and t h e gyro n u l l p o s i t i o n s were erroneously o r i e n t e d &a t l i f b f f . Beginning w i t h SA-9 t h e p la t forms were.space-fixed p r i o r t o i g n i t i o n and any torque appl ied t o t h e p l a t f o r m dur ing t h r u s t bui,ldup was sensed by t h e gyros and a torque equal and opposi te i n s i g n was generated thus s t a b i l i z i n g t h e p la t form. The l e v e l i n g and azimuth e r r o r s shown f o r SA-9, SA-8 and S A - I O a re we l l w i t h i n t h e 3a to lerances.
The re'l a t i ve I arge
Figures 5-3 and 5-4 show t h e d i f f e r e n c e s between computed and pre- d i c t e d p l a t f o r m system.errors. d i f f e r e n c e value i s r e l a t i v e l y large, t h e a n a l y s i s ind ica ted an e r r o r
In p r a c t i c a l l y every case where t h e
29
. .
opposi te i n s i g n t o t h e p r e d i c t i o n . good and e s p e c i a l l y good i f t h e s ign conventlon Is disregarded. magnitudes o f the e r r o r s determined from t h e p o s t f l i g h t andlyses were genera l l y very c lose t o pred ic t idns .
The comparisons i n general a re very The
Considerations have been g iven t o incorpora t ing guidance e r r o r correc- t i o n s ' i n the f l i g h t equat ions t o compensate for p r e f l i g h t measurments. Based on the r e s u l t s of t h e Saturn I Block I 1 guldance e r r o r analyses, it I s f e l t t h a t e f f e c t i v e l y large accelerometer e r r o r s could be compensated f o r i n t h e f l i g h t equations. However, gyro d r i f t r a t e compensation would be quest ionable u n t i l some a d d i t i o n a l analyses are made using t h e f l i g h t data from vehic les c a r r y i n g t h e ST-124 M p la t fo rms.
Table 5-1 shows t h e averages of t h e guidance e r r o r comparisons ( a n a l y s i s These averages for t h e accelerometer e r r o r measurements, minus p r e d i c t i o n ) .
b i a s and scale fac to r , show t h a t p r e f l i g h t est imates were general i y good. The i n i t i a l p l a t f o r m al ignment e r r o r s f o r t h e l a s t t h r e e veh ic les were held w i t h i n t h e 3a to lerances w i t h an average value o f - +0.31 X I O - * degrees.
The average d i f f e r e n c e of t h e constant d r i f t e r r o r s was s l i g h t l y less than t h e 30 value of 0.75 deg/hr. s e n s i t i v e d r i f t s was 0.07 deg/hr/g compared t o a ,3a value o f 0.05 deg/hr/g. However, if t h e s ign convention i s disregarded, ..the averages o f t h e d i f f e r e n c e i n magnitude would be 0.034 deg/hr and 0.038 deg/hr/g f o r constant and "g"-sensi t ive d r i f t s , respec t ive ly .
The average d i f f e r e n c e I n t h e "g"-
The missions of t h e Saturn I Block I I veh ic les d i d no t r e q u i r e more accurate guidance hardware. Howdver, based on t h e comparisons shown prev ious ly , t h e use o f advanced q u a l i t y c o n t r o l techniques i n s e l e c t i n g t h e i n d i v i d u a l components o f t h e guidance system hardware a l ready de- signed would insure t h e f u l f i l m e n t o f t h e terminal c o n d i t i o n s t o h igh degree o f accuracy. Correct ions f o r accelerometer e r r o r s could be pro- grammed i n t h e f l i g h t computer. Programming of c o r r e c t i o n s f o r gyro d r i f t s would be somewhat quest ionable u n t i l t e s t s show t h a t ''g"-sensi- t i v e d r i f t s a re more repeatable.
30
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1 .
2.
I
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4.
5 .
6.
Q)) REFERENCES
MPR-SAT-FE-64-15, A D r i l I . 1964. Resu l t s of The F i f t h Saturn I Launch Veh ic le Test ' F I i g h t (W, -Sa tu rn F I i g h t Eva lua t i on Working Group.
MPR-SAT-FE-64-16, August 7, 1964, Resu l ts of The S i x t h Saturn I Launch Veh ic le Test F l i g h t @, Saturn F l i g h t Eva lua t i on Working Group.
MPR-SAT-FE-64-17, November 25, 1964, Resu l t s o f The Seventh Saturn I Launch Veh ic le Tes t F l i g h t m), Saturn F l i g h t Eva lua t i on Working Group.
MPR-SAT-FE-65-6, A p r i l Launch Veh i c I e Test F I Group.
MPR-SAT-FE-65-6, J u l y Launch Veh ic le Test FI Group.
30, 1965, Resu l t s of The E g h t w, Saturn F I i g h t Eva
27, 1965, Resu l ts of The N g h t m, Saturn F I i g h t Eva
gh th Saturn I u a t i on Working
n t h Saturn I u a t i on Working
MPR-SAT-FE-65,14, September 4, 1965, Resu l ts of The Tenth Saturn I Launch Veh ic le Test F l i g h t 1, Saturn F l i g h t Eva lua t i on Working Group. a
36
APPROVAL TM X-53338
SATURN I BLOCK - I I GU I DANCE SUMMARY REPORT
By R. A. Chapman
The in fo rmat ion i n t h i s repo r t has been reviewed for s e c u r i t y c l a s s i f i c a t i o n . Review of any in fo rmat ion concerning Department o f Defense or Atomic Energy Commission programs has been made by t h e MSFC Secur i t y C l a s s i f i c a t i o n O f f i c e r . The highest c l a s s i f i c a t i o n has been determined t o be Con f iden t ia l .
Th is r e p o r t has been reviewed and approved f o r techn ica l accuracy.
A k d A Car los C. Haafaod Ch ie f , F I i g h i Eva lua t ion Branch
Operations Studies D i v i s i o n
D i rec to r , Aero-Astrodynamics Laboratory
37
. D I STR I BUT I ON
D r . Rees, DEP-T
I Col. James, I-I/IB-MGR D r . Speer, I-MO-MGR
-
RAD M r . Weidner, R-DIR -
R-AERO D r . Ge iss le r , R-AERO-DIR M r . Jean, R-AERO-DIR M r . Lindberg, R-AERO-F ,h-. Hagood, R-AERO-FF M r . Stone, R-AERO-FM M r . McNa i r, R-AERO-P M r . W i nch, R-AERO-DA Mrs. Chandler, R-AERO-DAG M r . Sheats, R-AERO-FFR M r . Chapman, R-AERO-FFR ( I O ) M r . Horn, R-AERO-D M r . Har t , R-AERO- G M r . Baker, R-AERO-G
R-ASTR D r . Haeusserman, R-ASTR-DIR M r . F e r r e l I , R-ASTR-GSA M r . N ica ise , R-ASTR-NGI M r . Mandel, R-ASTR-G M r . Mack, R-ASTR-S M r . D i gesu, R-ASTR-A M r . H. Thomason, R-ASTR-G M r . Moore, R-ASTR-N M r . S. Se l tzer , R-ASTR-NG
R-COMP M r . Houston, R-COMP-RRM ( 2 )
MSC M r . Henson, MSC-EG -
EXTERN A L I n t e r n a t i o n a l Business Machines System Design, Dept. 229 150 Sparkman D r i v e NW H u n t s v i l l e , Alabama 35808 A t t n : R. E. Poupard ( 2 )
Ron Avery ( I 1
38
cc-P I-RM-M MS-H MS-IP MS-IL (8) MS-T Mr . Bland ( 5 ) M r . Sulette
Scientific and Technical Information Facility (25) Attn: NASA Representative (S-AK/ RKT)
P. 0. Box 33 College Park, Maryland 20740
C . A. Cassoly Projects Aeronautical Material Laboratory Naval Aeronautical Engineering Center Philadelphia 12, Pa.
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