Mariner Mars 1971 Press Kit
Mariner Mars 1971 Press Kit
Mariner Mars 1971 Press Kit
PROJECT:
GY'
(CODE)
?r (CATEGORY)
- -
GENERAL RELEASE----------------------------
S MISSION CAPSULE---------------------------------------------
MARINER PLANETARY MISSIONS----------------------------------
7
8-9
S MARINER A I M I N G ZONES----------------------------------------
MISSIONS---------------------------------------------------- 11
M a r i n e r H - Mapping M i s s i o n A---------------------------- 11-13
M a r i n e r I - V a r i a b l e F e a t u r e s M i s s i o n B------------------13-15
10
MARINER SPACECRAFT------------------------------------------l6-29
Data Automation Subsystem--------------------------------20
A t t i t u d e Contpol----------------------------------------- 20-21
Propulsion----------------------------------------------- 21-22
C e n t r a l Computer and Sequencer--------------------------- 22-23
Comications------------------------------------------- 23-25
Power---------------------------------------------------- 26-27
Temperature Control-------------------------------------- 27-29
Scan Platform-------------------------------------------- 29
SCIENTIFIC EX~ERI~NTS-------------------------------------- 30-43
Television----------------------------------------------- 32-36
I n f r a r e d Radiometer (IRR)-------------------------------- 36-38
U l t r a v i o l e t Spectrometer--------------------------------- 38-40
I n f r a r e d I n t e r f e r o m e t e r S p e c t r o m e t e r (IRIS)-------------- 40
S-Band O c c u l t a t i o n Experiment----------------------------40-42
C e l e s t i a l Mechanics-------------------------------------- 42-43
MARINER MARS 1 9 7 1 SCIENCE EXPERIMENTS AND INVESTIGATORS----- 44-46
ATLAS-CENTAUR LAUNCH VEHICLE-------------------------------- 47-53
Launch V e h i c l e Characteristics--------------------------- 49
A t l a s - C e n t a u r F l i g h t Sequence - AC-23-------------------- 50
A t l a s - C e n t a u r F l i g h t Sequence - AC-24-------------------- 51
F l i g h t Sequence------------------------------------------ 52-53
TRACKING AND DATA SYSTEM AND MISSION OPERATIONS------------- 56-59
M i s s i o n Operations---------------------------------------- 58-59
NEWS WASHINGTON,D .C. 20546 TELS:
M a r i n e r H h a s b e e n mated t o A t l a s - C e n t a u r 2 4 and is
p e r i o d , an e x t e n d e d m i s s i o n t o l a s t up t o one y e a r i s being
considered.
The o b j e c t i v e s o f t h e M a r i n e r s a r e t o s t u d y t h e s u r -
f a c e and a t m o s p h e r e o f Mars i n d e t a i l and o v e r a p e r i o d o f
time, t o provide a broad p i c t u r e of t h e h i s t o r y of t h e p l a n e t
and n a t u r a l p r o c e s s e s c u r r e n t l y s h a p i n g t h e Ma r t i a n environment
To a c c o m p l i s h t h e s e , o n e s p a c e c r a f t w i l l map 7 0 % o f t h e
p l a n e t a n d t h e o t h e r w i l l r e p e a t e d l y s t u d y s e l e c t e d a r e a s on
Mars t o o b s e r v e c h a n g e s on t h e s u r f a c e and i n t h e a t m o s p h e r e ,
R e c u r r i n g phenomena s u c h as d u s t s t o r m s , c l o u d s and s e a s o n a l
c h a n g e s i n t h e a p p e a r a n c e o f t h e p l a n e t ' s s u r f a c e have been
o b s e r v e d on Mars. The o r b i t a l m i s s i o n s w i l l a l l o w s c i e n t i s t s
t o s t u d y t h e s e phenomena d a i l y a t c l o s e r a n g e .
The M a r i n e r s w i l l c a r r y i d e n t i c a l p a y l o a d s o f i n s t r u m e n t s
t o allow each s p a c e c r a f t t o conduct s i x s c i e n t i f i c i n v e s t i g a -
tions:
- M a r t i a n t o p o g r a p h y and v a r i a b l e f e a t u r e s w i t h two
t e l e v i s i o n c a m e r a s , one w i t h a w i d e - a n g l e l e n s and one w i t h a
telephoto lens;
- s u r f a c e t e m p e r a t u r e measurements w i t h an i n f r a r e d
radiometer;
- c o m p o s i t i o n and s t r u c t u r e o f t h e a t m o s p h e r e w i t h a n
u l t r a v i o l e t spectrometer;
The l a t t e r two e x p e r i m e n t s i n v o l v e m e a s u r e m e n t s o f t h e
M a r i n e r s 1 r a d i o s i g n a l s b a c k t o E a r t h a n d do n o t r e q u i r e
s p e c i a l i n s t r u m e n t s on t h e s p a c e c r a f t .
The s c i e n t i f i c e x p e r i m e n t s h a v e b e e n teamed t o g e t h e r t o
p r o v i d e a maximum o f c o r r e l a t i o n o f t h e d a t a t h e y g a t h e r , The
t h r e e i n s t r u m e n t s on t h e s c a n p l a t f o r m , f o r i n s t a n c e , a r e
b o r e - s i g h t e d w i t h t h e t e l e v i s i o n cameras s o t h a t t h e photo-
g r a p h y c a n be c o r r e l a t e d w i t h m e a s u r e m e n t s o f t h e M a r t i a n
atmo s p h eri c and s u r f a c e c h a r a c t e r i s t i c s .
f a i l s a t a n y t i m e up t o f i v e d a y s b e f o r e o r b i t a l i n s e r t i o n ,
t h e m i s s i o n o f t h e s e c o n d s p a c e c r a f t w i l l be r e v i s e d t o per-
form s i g n i f i c a n t p a r t s of b o t h m i s s i o n s .
i n 20 and one h a l f h o u r s , i n c l i n e d 50 d e g r e e s , w i t h a n
a p o a p s i s o f 20,500 m i l e s ( 2 8 , 6 0 0 k i l o m e t e r s ) a n d p e r i a p s i s
s p a c e c r a f t t o o b s e r v e s e l e c t e d a r e a s o f Mars r e p e a t e d l y
every f i v e days o r s i x o r b i t s .
The s p a c e c r a f t w i l l e a c h weigh a p p r o x i m a t e l y 2 , 2 0 0
pounds ( 1 , 0 0 0 k i l o g r a m s ) a t l a u n c h , w i t h a b o u t 1 , 0 0 0 pounds
(454 k i l o g r a m s ) o f f u e l f o r t h e 300-pound t h r u s t r e t r o e n g i n e .
A f t e r i n j e c t i o n i n t o Mars o r b i t , t h e s p a c e c r a f t w i l l weigh
a p p r o x i m a t e l y 1 , 2 0 0 pounds (544 k i l o g r a m s ) .
O r b i t i n s e r t i o n w i l l r e q u i r e a b o u t a 14-minute b u r n o f t h e
r e t r o e n g i n e s l o w i n g t h e s p a c e c r a f t by a b o u t 3 , 2 5 0 m i l e s - p e r -
r e l a t i v e t o Mars p r i o r t o t h e b u r n w i l l be a b o u t 1 1 , 0 0 0
mph ( 4 , 9 2 0 m / s e c ) .
The l a u n c h e s w i l l be d i r e c t a s c e n t w i t h o u t a p a r k i n g
orbit. The l a u n c h a i m i n g p o i n t w i l l be a t s u c h a d i s t a n c e
f r o m Mars as t o i n s u r e t h a t n e i t h e - - . s p a c e c r a f t n o r t h e C e n t a u r
s e c o n d s t a g e w i l l i m p a c t Mars i n t h e e v e n t o f l o s s o f c o n t r o l
a r e d e s i g n e d t o g u a r a n t e e t h a t t h e * w i l l n o t i m p a c t Mars
f o r a t l e a s t 1 7 y e a r s , t o a v o i d c o ~t a m i n a t i o n o f t h e p l a n e t
b e f o r e s t u d i e s a r e c o n d u c t e d on t h e s u r f a c e by l a n d i n g s p a c e -
craft. -more-
F o l l o w i n g s u c c e s s f u l i n j e c t i o n i n t o s o l a r o r b i t , two
m i d c o u r s e maneuvers may b e p e r f o r m e d t o c o r r e c t t h e t r a -
be u s e d f o r m i d c o u r s e m a n e u v e r s .
The a c c u r a c y r e q u i r e d t o o r b i t Mars i s u n p r e c e d e n t e d
of t h e 287-million-mile (462-million-kilometer) f l i g h t i s an
a r e a a b o u t 435 m i l e s ( 1 , 1 6 5 k i l o m e t e r s ) s q u a r e .
A f t e r i n s e r t i o n i n t o Mars o r b i t , t h e s p a c e c r a f t w i l l s e
t r i m s w i l l be p r o v i d e d by t h e r e t r o e n g i n e .
The maximum d a t a t r a n s m i s s i o n r a t e w i l l be 1 6 , 2 0 3 b i t s -
p e r - s e c o n d when t h e s p a c e c r a f t c a n t r a n s m i t t o t h e s e n s i t i v e
s t a t i o n s w i l l r e c e i v e a t a maximum r a t e o f 2 , 0 2 5 b i t s - p e r -
second.
p r o j e c t r e s p o n s i b i l i t y i n c l u d i n g m i s s i o n o p e r a t i o n s end t r a c k -
i n g and d a t a a c q u i s i t i o n t o t h e J e t P r o p u l s i o n Labora'sory
managed by t h e C a l i f o r n i a I n s t i t u t e o f T e c h n o l o g y . The
l a u n c h v e h i c l e i s t h e r e s p o n s i b i l i t y o f t h e Lewis R e s e a r c h
and Data A c q u i s i t i o n .
$129 m i l l i o n , e x c l u s i v e o f l a u n c h v e h i c l e s and d a t a
acquisition,
Experiments :
1. Two t e l e v i s i o n c a m e r a s , o n e n a r r o w a n g l s and
one wide a n g l e .
2. Infrared radiometer.
3. Ultraviolet spectrometer.
5. C e l e s t i a l mechanics.
6 . O c c u l t a t i o n . The l a t t e r two e x p e r i m e n t s d o
not require special instruments.
MARINER I - S t u d y s u r f a c e f e a t u r e s and a t m o s p h e r e a s
MISSION -
B t h e y change i n t i m e .
MARINER I 20,500 m i l e s ( 2 8 , 5 7 9 k i l o m e t e r ) a p o a p s i s t o
B ORBIT
- 530 m i l e s ( 8 5 0 k i l o m e t e r ) p e r i a p s i s . Incli-
- n a t i o n , 50 d e g r e e s . P e r i o d i s 20 1 / 2 h o u r s ,
3-
GZ*
z> *
wwm
Gad
I
<WL
z-
MARINER PLANETARY MISSIONS
- -1
- - I- - -
T h e r e a r e two m i s s i o n s t o b e p e r f o r m e d a t Mars e a c h
w i t h s p e c i f i c o b j e c t i v e s and a s p e c i f i c o r b i t . Should o r e
M a r i n e r s p a c e c r a f t f a i l , t h e o t h e r w i l l combine a s many o f
t h e o b j e c t i v e s of b o t h m i s s i o n s as p o s s i b l e .
Mariner -
H - Mapping M i s s i o n &
The o b j e c t i v e o f t h i s m i s s i o n i s t o map 70 p e r c e n t
of Mars a t a r e s o l u t i o n o f 3,280 f e e t ( 1 , 0 0 0 m e t e r s ) .
High r e s o l u t i o n p h o t o g r a p h s a t a r e s o l u t i o n of 328 pee^
(100 m e t e r s ) , n e s t i n g i n s i d e t h e w i d e - a n g l e p h o t o g r a p h s ,
w i l l cover 5 p e r c e n t of t h e s u r f a c e .
The o r b i t a l p e r i o d f o r t h e mapping m i s s i o n w i l l be
f i x e d a t 12 hours. This w i l l allow twice-daily observations
n e a r p e r i a p s i s each w i t h a subsequent t r a n s m i s s i o n of
recorded d a t a a t t h e h i g h b i t r a t e of 16,200 b i t s p e r
s e c o n d t o t h e 2 1 0 - f o o t ( 6 4 - m e t e r ) a n t e n n a of t h e Deep
S p a c e Network a t G o l d s t o n e .
Following i n s e r t i o n i n t o o r b i t , t h e s p a c e c r a f t w i l l .
be t r a c k e d f o r a s u f f i c i e n t p e r i o d t o allow c a l c u l a t i o n of
r e q u i r e d t r i m m i n g o f t h e o r b i t t o s e c u r e t h e p r e c i s e orrPt
desired.
I n a typical o r b i t the spacecraft w i l l :
1. P l a y b a c k d a t a i n i t s t a p e r e c o r d e r (this
r e q u i r e s t h r e e h o u r s ) t a k e n on t h e p r e v i o u s o r b i t ,
2. Take TV, i n f r a r e d and u l t r a v i o l e t d a t a f o r
s t o r a g e on t h e t a p e r e c o r d e r ( I R and UV d a t a i s a l s o
transmitted i n r e a l t i m e a t 8,000 b i t s p e r s e c o n d whefi
t h e l a r g e Goldstone antenna can be used);
3 . E n t e r t h e o c c u l t a t i o n zone s h o r t l y a f t e r t h e
recorder i s f i l l e d ;
4 . Following o c c u l t a t i o n , t h e s p a c e c r a f t w i l l
s t i l l be i n v i e w of G o l d s t o n e and t h e r e c o r d e d d a t z i s
transmitted.
On t h e n e x t o r b i t , G o l d s t o n e i s n o t i n v i e w . The
r e c o r d e r i s f i l l e d a g a i n and t h e i?ata h e l d u n t i l t h e
following o r b i t .
- more --
Because t h e o r b i t a l p e r i o d i s 12 h o u r s and t h e r o t a t i o n
r a t e o f Mars i s a b o u t 24 h o u r s 37 m i n u t e s , t h e p l a n e t w i l l
r o t a t e s l i g h t l y l e s s t h a n 180 degrees p e r s p a c e c r a f t o r b i t .
Mapping c o v e r a g e , t h e r e f o r e , w i l l a l t e r n a t e f r o m one s i d e of'
t h e p l a n e t t o t h e o t h e r . A c o m p l e t e mapping c i r c u i t a.rou.nd
Mars w i l l b e c o m p l e t e d i n a b o u t 20 d a y s . A f t e r 9 0 d a y s , t h e
a r e a b e t w e e n -60 and + 4 O d e g r e e s l a t i t u d e w i l l h a v e been
covered.
A f t e r 90 t o 1 0 0 d a y s i n o r b i t , d e p e n d i n g on t h e a c t u a l
performance of t h e h i g h - r a t e channel, t h e i n c r e a s i n g Earth-
Mars d i s t a n c e a n d t h e s p a c e c r a f t a n t e n n a o r i e n t a t i o n w i l l
c a u s e t h e t a p e p l a y b a c k r a t e t o b e d r o p p e d t o 8,10C b i t s p e r
second, even w i t h t h e u s e o f t h e 210-foot (64-meter) a r ~ t e n n a .
A t t h a t t i m e , e i t h e r a f u l l t a p e r e c o r d e r o f d a t a w i l l be
t a k e n on e v e r y o t h e r o r b i t o r h a l f t h e amount of d a t a wi;l be
t a k e n on e a c h o r b i t .
S e v e r a l days l a t e r d a t a r a t e s w i l l have t o b e f u r t h e r
r e d u c e d , as t h e main l o b e o f t h e s p a c e c r a f t antenna. beam
moves away from E a r t h , u n t i l d a t a r a t e s o f 4,000 b i t s o r
2,000 b i t s p e r s e c o n d s t a b i l i z e f o r e x t e n d e d
Mariner -
I - Variable Features Mission B
-
The o b j e c t i v e o f t h i s m i s s i o n i s t o s t u d y c h a n g e s cn
t h e s u r f a c e and i n t h e a t m o s p h e r e o f Mars o v e r a p e r i o d o f
time .
The p e r i o d o f t h e o r b i t , 2 0 . 5 h o u r s , was s e l e c t e d t o
p r o v i d e r e p e a t e d s t u d i e s o f a s e r i e s of s i x a d j a c e n t s i t e s
g i r d l i n g t h e planet i n f i v e days.
The r e l a t i o n s h i p b e t w e e n t h e s p a c e c r a f t o r b i t a l p e r i o d
of 20 1 / 2 h o u r s and M a r ' s r o t a t i o n a l p e r i o d o f 24 h o u r s
37 m i n u t e s , p l a c e s t h e cameras o v e r t h e s i x a d j a c e n t a r e a s
in s i x o r b i t s . Repeat coverage begins w i t h t h e seventh o r b i t
at t h e beginning of t h e s i x t h day.
The t i m e r e l a t i o n s h i p i s a c h i e v e d by s e l e c t i n g a s p a c e -
craft v e l o c i t y r e s u l t i n g i n a n o r b i t w i t h a h i g h p o i n t of
20,000 m i l e s ( 2 8 , 5 7 9 k i l o m e t e r s ) and a low p o i n t o f 530 T - i l e s
(850 k i l o m e t e r s ) .
- more -
A typical orbit w i l l p r o v i d e f u l l d i s c c o v e r a g e , high
Sun a n g l e p h o t o g r a p h y f o r a l b e d o s t u d i e s , low and h i g h
r e s o l u t i o n s t u d i e s by t h e i n f r a r e d and u l t r a v i o l e t i n s t r u -
ments, E a r t h o c c u l t a t i o n , and d a r k s i d e UV and I R d a t a ,
The two moons of Mars, Phobos and Deimos, may be mapped
by t h e t e l e v i s i o n e x p e r i m e n t and p r o b e d by t h e i n f r a r e d and
u l t r a v i o l e t experiments.
O b s e r v a t i o n s o f s t a r f i e l d s and S a t u r n a l s o may b e u s e d
t o c a l i b r a t e t h e cameras.
It i s p l a n n e d , when p o s s i b l e , t o u s e a n a d a p t i v e mode
i n p l a n n i n g s c i e n c e o p e r a t i o n s f r o m o r b i t . I n t h i s mode,
an i n t e r e s t i n g f e a t u r e seen i n previous photographs can b e
s p e c i f i c a l l y re-examined i n s u b s e q u e n t p a s s e s t h a t c o v e r
t h a t a r e a . I t i s a l s o p o s s i b l e , d e p e n d i n 6 on t h e amount
of f u e l r e m a i n i n g a f t e r a t t a i n i n g o r b i t , t o change a
s p a c e c r a f t o r b i t t o r e p e a t e d l y c o v e r a n a r e a of u n u s u a l
activity or significance.
- more -
MARINER SPACECRAFT
c o m p a r t m e n t s . The c o m p a r t m e n t s t h e m s e l v e s p r o v i d e s t - ? u c $ ~ r a l
support t o the spacecraft.
F o u r s o l a r p a n e l s , e a c h 84 1 / 2 i n c h e s ( 2 . 1 4 m e t e r s ) long
and 35 1 / 2 i n c h e s ( 0 . 9 0 2 m e t e r s ) w i d e , a r e a t t a c h e d b y ou%-
r i g g e r s t r u c t u r e s t o t h e t o p o r sunward s i d e o f t h e o c t a g o n ,
Each p a n e l h a s a s o l a r c e l l a r e a 2 0 . 7 f e e t ( 1 . 9 2 m e t e r s ) square,
o r a t o t a l c e l l s u r f a c e o f a p p r o x i m a t e l y 83 s q u a r e f e e t i7*8
square meters) f o r each s p a c e c r a f t .
Two s e t s o f a t t i t u d e c o n t r o l j e t s c o n s i s t i n g o f s i x , e t s
e a c h , w h i c h s t a b i l i z e t h e s p a c e c r a f t on t h r e e a x e s , a r e ~ o u n t e d
a t t h e t i p s o f t h e f o u r s o l a r p a n e l s . T i t a n i u m b o t t l e s @or-
t a i n i n g t h e n i t r o g e n gas supply f o r Mariner's dual a t r i t a d e
c o n t r o l g a s s y s t e m and r e g u l a t o r s f o r t h e s y s t e m s a r e n?03r\ted
on t h e t o p r i n g o f t h e o c t a g o n .
Two s p h e r i c a l p r o p e l l a n t t a n k s f o r t h e l i q u i d - f u e l e d
r o c k e t e n g i n e a r e ' mounted s i d e by s i d e a t o p t h e o c t a g o n a l
s t r u c t u r e w i t h t h e r o c k e t n o z z l e p r o t r u d i n g between t h e t a z k s ,
The t i t a n i u m t a n k s a r e 30 i n c h e s ( 0 . 7 6 2 m e t e r s ) i n d i a m e t e r ,
The t w o - p o s i t i o n h i g h - g a i n a n t e n n a i s a t t a c h e d t o t n e
s p a c e c r a f t by a s u p e r s t r u c t u r e a t o p t h e o c t a g o n . I t s aluminum
honeycomb d i s h r e f l e c t o r i s c i r c u l a r , 40 i n c h e s ( l r 0 2 m e t e r s )
i n d i a m e t e r , and i s p a r a b o l i c i n c r o s s - s e c t i o n . The a n t e n c a
f e e d i s s u p p o r t e d a t t h e f o c u s o f t h e p a r a b o l a by a I Y b e r g l a s s
t r u s s . The t w o - p o s i t i o n c a p a b i l i t y a l l o w s t h e E a r t h t o b e
c e n t e r e d i n t h e a n t e n n a beam d u r i n g b o t h p r e - o r b i t and t h e
o r b i t a l periods of t h e mission.
The l o w - g a i n o m n i d i r e c t i o n a l a n t e n n a i s mounted a t t h e
t o p o f a c i r c u l a r aluminum t u b e , f o u r i n c h e s ( 1 0 . 2 c e n t i m e t e r s )
i n d i a m e t e r and e x t e n d i n g v e r t i c a l l y 57 i n c h e s ( 1 . 4 5 m e t e r s )
f r o m t h e t o p o f t h e o c t a g o n a l s t r u c t u r e . The t u b e a c t s as a
waveguide f o r t h e a n t e n n a .
Z
3
m
--
,,a
--
b 0
i-.-
0
Z
-
P-
3
ad
hL
I-"
d-
*<
-a
M
L-
7
---
8
I-
4
'4
1
3
cn
z
--
I L L
vm-
L>d
I, ,, 0
L+L
&Z
"
QL
+-Z
*<
c,
p"" 0-
(Ld
--v
*L
Ek g
bd
\i
& "if3
Lh
-r a
A h o r n - s h a p e d medium-gain a n t e n n a i s mounted on a
s o l a r p a n e l o u t r i g g e r s o t h a t i t i s p o i n t e d toward E a r t h
d u r i n g s p a c e c r a f t i n s e r t i o n i n t o Mars o r b i t .
The Canopus s t a r t r a c k e r a s s e m b l y i s l o c a t e d on t h e
upper r i n g s t r u c t u r e o f t h e octagon f o r a c l e a r f i e l d of
v i e w between two s o l a r p a n e l s . The c r u i s e Sun s e n s o r ar.d
Sun g a t e a r e a t t a c h e d t o a s o l a r p a n e l o u t r i g g e r .
The e i g h t e l e c t r o n i c s compartments g i r d l i n g t h e s p a c e -
c r a f t house t h e f o l l o w i n g : Bay 1, power r e g u l a t o r s ; B a y 2 ,
power c o n v e r s i o n e q u i p m e n t , s c a n c o n t r o l a n d I R I S e l e c t r ~ ~ i c s ;
Bay 3 , C e n t r a l C3mputer and S e q u e n c e r and a t t i t u d e c o n t r o l
s u b - s y s t e m ; Bay 4, f l i g h t t e l e m e t r y and command s u b s y s t e m s ;
Bay 5 , t a p e r e c o r d e r ; Bay 6 , r a d i o r e c e i v e r and t r a n s m L t t e r s ;
Bay 7 , t e l e v i s i o n e l e c t r o n i c s and d a t a a u t o m a t i o n su.bsystem;
Bay 8 , s p a c e c r a f t b a t t e r y .
S i x o f t h e e l e c t r o n i c s c o m p a r t m e n t s a r e t e m p e r a t u r e cop-
t r o l l e d by l i g h t w e i g h t l o u v e r a s s e m b l i e s on t h e o u t e r s u r f a c e s ,
The o c t a g o n ' s i n t e r i o r i s i n s u l a t e d by m u l t i l a y e r f ' a b r l c
t h e r m a l b l a n k e t s a t b o t h t o p and b o t t o m of t h e s t r u c t u r e ,
To a v o i d p u n c t u r e of t h e p r o p e l l a n t t a n k s by micro-,
meteoroids, the outer l a y e r of the top thermal blanket i s
c o n s t r u c t e d of a tightly-woven f i b e r g l a s s c l o t h (A~malon)
d e s i g n e d t o b r e a k up s t r i k i n g p a r t i c l e s ,
The M a r i n e r s w i l l c a r r y s c i e n c e i n s t r u m e n t a t i o ~f o r P o u r
p l a n e t a r y e x p e r i m e n t s . Two a d d i t i o n a l e x p e r i m e n t s - - s p a c e c r a f t
o c c u l t a t i o n by Mars and c e l e s t i a l m e c h a n i c s - - r e q u i r e o n l y t h e
s p a c e c r a f t c o m m u n i c a t i o n s s y s t e m as t h e s o u r c e o f t h e i r Cats*
Two t e l e v i s i o n c a m e r a s , a n i n f r a r e d i n t e r f e r o m e t e r
s p e c t r o m e t e r ( I R I S ) , u l t r a v i o l e t s p e c t r o m e t e r (UVS) and
i n f r a r e d r a d i o m e t e r (IRR) a r e mounted on a m o t c r - d r i v e n two-
d e g r e e - o f - f r e e d o m s c a n p l a t f o r m on t h e b o t t o m o r s h a d e d s i d e
of t h e octagon. T o t a l r o t a t i n g weight o f t h e platform
mechanism and i t s s c i e n c e i n s t r u m e n t p a y l o a d i s 1 8 1 pou-nds
(82.2 k i l o g r a m s ) .
Each M a r i n e r w e i g h s 1 , 2 0 0 pounds ( 5 4 4 k i l o g r a m s ) u n f u e l e e
and m e a s u r e s 7 1 / 2 f e e t ( 2 . 2 9 m e t e r s ) f r o m t h e s c a n p l a t f o r m
t o t h e t o p o f t h e low-gain a n t e n n a a n d r o c k e t n o z z l e , W i t h
s o l a r p a n e l s d e p l o y e d , t h e s p a c e c r a f t s p a n s 22 f e e t , 7 1 1 2
i n c h e s ( 4 . 3 5 m e t e r s ) . The o c t a g o n a l s t r u c t u r e m e a s u r e s 54 1 / 2
i n c h e s ( 1 . 3 9 m e t e r s ) d i a g o n a l l y and 1 8 i n c h e s ( 0 . 4 5 7 m e t e r s )
i n depth.
The f i v e s c i e n c e i n s t r u m e n t s on t h e s p a c e c r a f t a r e
on trolled a n d s y n c h r o n i z e d by t h e Data A u t o m a t i o n Sub-
s y s t e m (DAS) and d a t a f r o m t h e i n s t r u m e n t s a r e c o n v e r t e d
by t h e DAS i n t o d i g i t a l f o r m f o r t r a n s m i t t a l t o E a r t h ,
The e x p e r i m e n t s c o n t r o l l e d by t h e DAS a r e t e l e v i s i o n ,
i n f r a r e d radiometer, i n f r a r e d interferometer spectrometer
a n d u l t r a v i o l e t s p e c t r o m e t e r . The S-band o c c u l t a t i o n
e x p e r i m e n t a n d t h e c e l e s t i a l m e c h a n i c s e x p e r i m e n t do n o t
r e q u i r e s p e c i a l equipment aboard t h e s p a c e c r a f t and a r e n o t
c o n t r o l l e d by t h e DAS.
The DAS c o n t r o l s i n s t r u m e n t s e q u e n c i n g , a c c u m u l a t e s
v a r i e d s c i e n c e d a t a , r e d u c e s them t o a common d i g i t a l f o r m
a n d common r a t e a n d t h e n f e e d s t h e d a t a t o t h e t a p e r e c o r d e r
o r t o t h e s e l e c t e d s c i e n c e t e l e m e t r y channel a t proper i n t e r -
vals f o r transmission t o Earth.
Attitude Control
S t a b i l i z a t i o n o f t h e s p a c e c r a f t i s p r o v i d e d by a s y s t e m
o f 1 2 c o l d g a s j e t s mounted a t t h e o u t e r e n d s o f t h e f o u r
s o l a r p a n e l s . The j e t s a r e l i n k e d by l o g i c c i r c u i t r y t o
t h r e e gyroscopes (one gyro f o r each of t h e s p a c e c r a f t ' s t h r e e
a x e s ) , t o t h e Canopus s e n s o r and Sun s e n s o r s .
The g a s s y s t e m i s d i v i d e d i n t o two s e t s o f s i x j e t s ,
e a c h s e t c o m p l e t e w i t h i t s own g a s s u p p l y , r e g u l a t o r s , l i n e s
and v a l v e s s o t h a t a l e a k o r v a l v e f a i l u r e w i l l n o t d e p l e t e
t h e g a s and j e o p a r d i z e t h e m i s s i o n . Each s y s t e m i s f e d b y a
titanium b o t t l e containing nitrogen gas pressurized a t 2,500
pounds-per-square-inch ( 1 7 5 . 7 kilograms-per-square-centime-tex")*
Normally, b o t h s e t s w i l l o p e r a t e d u r i n g t h e m i s s i o n . E i t h e r
system can s u p p o r t t h e e n t i r e f l i g h t i n t h e e v e n t o f a f a i l u r e
i n the other.
The f i x e d s e q u e n c e r w i l l b e p r i m e f o r t h e maneuver t h a t
p u t s M a r i n e r i n t o o r b i t a r o u n d Ea.rs. S e l e c t e d backup func"ciol?s
w i l l b e p r o v i d e d by t h e programmable c o m p u t e r .
Communications
Two-way communications w i t h t h e M a r i n e r s w i l l be
by r a d i o l i n k b e t w e e n E a r t h t r a c k i n g s t a t i o n s and a
d u a l t r a n s m i t t e r - s i n g l e r e c e i v e r r a d i o system aboard
each s p a c e c r a f t .
The on-board c o m m u n i c a t i o n s s y s t e m a l s o i n c l u d e s a
t e l e m e t r y s u b s y s t e m , command s u b s y s t e m , d a t a s t o r a g e
s u b s y s t e m and h i g h - g a i n , low-gain and mediu.m-gain a n t e n n a s .
The s p a c e c r a f t S-band r e c e i v e r w i l l o p e r a t e c o n t i n u o u s l y
d u r i n g t h e m i s s i o n a t a b o u t 2,210 m e g a h e r t z . (The r e c e i v e r s
i n t h e two M a r i n e r s w i l l o p e r a t e a t s l i g h t l y d i f f e r e n t f r e -
q u e n c i e s . S i m i l a r l y , n o two t r a n s m i t t e r s w i l l o p e r a t e a t
e x a c t l y t h e same frequency.) The r e c e i v e r w i l l be u s e d w i t h
t h e h i g h - g a i n a n t e n n a o n l y o r a combination of t h e low-gain
o ~ ~ n i d i r e c t i o n a nl t e n n a and t h e medium-gain a n t e n n a . The
s p a c e c r a f t r e c e i v e s u p l i n k command and r a n g i n g s i g n a l s f r o m
g r o u n d s t a t i o n s o f t h e Deep Space Network
To p r o v i d e t h e s t a n d a r d d o p p l e r t r a c k i n g d a t a , t h e
r a d i o s i g n a l t r a n s m i t t e d from E a r t h i s r e c e i v e d a t t h e space-
c r a f t , changed i n f r e q u e n c y by a known r a t i o and r e - t r a n s m i t t e d
t o Earth. I n a d d i t i c n , a JPL-developed r a n g i n g t e c h n i q u e u s i n g
a n a u t c m a t i c coded s i g n a l p r o v i d e s r a n g e measurements with an
a c c u r a c y o f a few y a r d s a t t h e M a r s - E a r t h d i s t a ~ c e . The r a n g i n g
f u n c t i o n may b e commanded on a n d o f f by g r o u n d command, o r off
by t h e C e n t r a l Computer and S e q u e n c e r .
- more -
When no uplink signal is being received by Mariner,
the transmitted frequency of about 2,295 megahertz originates
in the spacecraft transmitter. The transmitter consists of
two redundant exciters and two redundant radio frequency
power amplifiers of which any combination is possible, Only
one exciter-amplifier combination will operate at any one
time. Selection of the combination will be by on-board
failure detection logic with ground command backup,
Both amplifiers on each spacecraft employ traveling
wave tubes and are capable of operating at 10 watts or 20
watts output and the signal may be transmitted through
either the high-gain or low-gain antenna. Transmission
via the high-gain antenna will be required during the
encounter and playback phases of the mission.
The high-gain antenna, with a 40-inch-diameter
(1.02 meters) parabolic reflector, provides a highly
directional beam for the downlink radio signal. The
high-gain antenna has two positions with respect to the
spacecraft. It is deployed to the second position during
orbit to enhance communications during the orbital phase.
The low-gain antenna provides essentially uniform coverage
in the direction of Earth. The medium-gain antenna, coupled
to the low-gain is used to provide telemetry to Earth during
the maneuver into Mars orbit.
All communications between the Mariners and Earth will
be in digital form. Command signals transmitted to .the
spacecraft will be decoded--translated from a binary form
into electrical impulses--in the command subsystem and routed
to their proper destination.
Three types of commands are transmitted to the space-
craft: a direct command (DC) results in the closure of a
switch in one of the spacecraft subsystems; a coded c o m ~ a n d
(CC) provides information to the Central Comp,uter and
Sequencer for maneuvers or to update the CC&S program; a
quantitative command (QC) is used to position the scan plat-
form. A coded command to the Data Automation System allows
selection of TV camera filters, shutter speeds and other
science instrument options. There are 82 possible D C q s
which back up all critical automatic spacecraft functions,
choose redundant elements, initiate maneuvers and perform
other functions.
- more -
Data t e l e m e t e r e d from t h e s p a c e c r a f t w i l l c o n s i s t
o f e n g i n e e r i n g and s c i e n c e measurements p r e p a r e d f o r
t r a n s m i s s i o n by t h e T e l e m e t r y S u b s y s t e m , t h e D a t a
A u t o m a t i o n S u b s y s t e m ( r e a l - t i m e TV a n d s c i e n c e ) and
D a t a S t o r a g e S u b s y s t e m ( r e c o r d e d s c i e n c e i n c l u d i n g TV),
The e n c o d e d i n f o r m a t i o n w i l l i n d i c a t e v o l t a g e s , p r e s s u r e s ,
t e m p e r a t u r e s and o t h e r v a l u e s m e a s u r e d by t h e s p a c e c r a f t
t e l e m e t r y s e n s o r s and s c i e n c e i n s t r u m e n t s .
T h e r e a r e t h r e e d a t a c h a n n e l s : t h e e n g i n e e r i n g cbanr~e;
which o p e r a t e s t h r o u g h o u t t h e f l i g h t ; t h e l o w - r a t e s c i e n c e
c h a n n e l employed d u r i n g t h e o r b i t a l p h a s e o f t h e m i s s i o n ;
and t h e h i g h - r a t e s c i e n c e c h a n n e l .
Mariner can t r a n s m i t i n f o r m a t i o n t o E a r t h a t e i g h t
d i f f e r e n t r a t e s : on t h e e n g i n e e r i n g c h a n n e l a t 8 1 / 3 b i t s
p e r s e c o n d and 3 3 1/3 b p s ; o n t h e s c i e n c e c h a n n e l a t 5 0 b p s ;
and on t h e h i g h - r a t e s c i e n c e c h a n n e l a t 1 6 , 2 0 0 b p s a n d 8,130
b p s . Data s t o r a g e playback r a t e s a r e 16,200 b p s , 8,100 b p s ,
4,050 b p s , 2 , 0 2 5 b p s a n d 1 , 0 1 2 . 5 b p s .
C e r t a i n c o n d i t i o n s must e x i s t i n o r d e r t o u t i l i z e t h e
high-rate channel. These i n c l u d e t h e a v a i l a b i l i t y of t h e
210-foot (64-meter) d i a m e t e r a n t e n n a a t t h e Goldstone
Complex of t h e Deep S p a c e Network (DSN) f o r r e c e i v i n g ,
The DSNvs 8 5 - f o o t ( 2 6 - m e t e r ) a n t e n n a s c a n r e c e i v e d a t a
a t r a t e s up t o 2 , 0 2 5 b p s .
A p p r o x i m a t e l y 90 e n g i n e e r i n g m e a s u r e m e n t s a r e o b t a i n e <
by t r a n s d u c e r s t h r o u g h o u t t h e s p a c e c r a f t t o make up t h e
e n g i n e e r i n g d a t a . The e n g i n e e r i n g s a m p l e s a r e t a k e n con-
t i n u o u s l y and c a n be t r a n s m i t t e d a l o n g w i t h s c i e n c e r e g a r d i e s s
of t h e s c i e n c e channel o r r a t e i n use.
The D a t a S t o r a g e S u b s y s t e m ( t a p e r e c o r d e r ) r e c o r c s d t g i t a l
s c i e n c e d a t a from t h e D a t a Automation System d u r i n g t h e o r k i t a i .
phase a t 132,300 b i t s p e r second u n t i l t h e e i g h t t a p e t r a c k s
a r e f i l l e d . D a t a c o n s i s t s of d i g i t i z e d v i d e o from t h e TV
c a m e r a s and t h e o t h e r s c i e n c e i n s t r u m e n t s . Total storage
c a p a c i t y f o r e a c h s p a c e c r a f t i s 180 m i l l i o n b i t s .
P l a y b a c k i s i n i t i a t e d by e i t h e r on-board o r ground
command. One o f t h e f i v e p l a y b a c k d a t a r a t e s -- from
1 , 0 1 2 . 5 b i t s p e r s e c o n d t o 1 6 , 2 0 0 b p s -- i s s e l e c t e d
d e p e n d i n g upon t h e a v a i l a b i l i t y o f t h e 2 1 0 - f o o t ( 6 4 - m e t e r )
G o l d s t o n e a n t e n n a and t h e Earth-Mars d i s t a n c e .
- more -
Power
The M a r i n e r power s u b s y s t e m s u p p l i e s e l e c t r i c a l
power t o t h e s p a c e c r a f t , s w i t c h e s a n d c o n t r o l s t h e power
and p r o v i d e s an a c c u r a t e t i m i n g source f o r t h e s p a c e c r a f t ,
P r i m a r y power s o u r c e i s a n a r r a n g e m e n t o f 1 7 , 4 7 2
p h o t o v o l t a i c s o l a r c e l l s mounted on f o u r p a n e l s which will
f a c e t h e Sun d u r i n g most o f t h e f l i g h t t o Mars a n d d u r i n g
o r b i t a l o p e r a t i o n s . The c e l l s , c o v e r i n g 83 s q u a r e f e e t
( 7 . 8 s q u a r e m e t e r s ) , w i l l c o l l e c t s o l a r e n e r g y and conver';
i t i n t o e l e c t r i c a l power.
A r e c h a r g e a b l e nickel-cadmium b a t t e r y p r o v i d e s space-
c r a f t power d u r i n g l a u n c h a n d whenever t h e p a n e l s a r e t u r n e d
away f r o m t h e Sun. The b a t t e r y w i l l b e k e p t i n a s t a t e o f
f u l l c h a r g e a n d w i l l b e a v a i l a b l e as a n emergency power
backup s o u r c e .
Two power r e g u l a t o r s w i l l p r o v i d e r e d u n d a n c y . i n t h e
event of a f a i l u r e i n o n e , i t w i l l b e removed a u t o m a t i c a l l y
from t h e l i n e a n d t h e s e c o n d w i l l b e s w i t c h e d i n t o assume
the f u l l load.
The s o l a r p a n e l s w i l l b e f o l d e d i n a n e a r v e r t i c a l
p o s i t i o n above t h e body o f t h e s p a c e c r a f t d u r i n g l a u n c h
and w i l l b e d e p l o y e d a f t e r s e p a r a t i o n f r o m t h e l a u n c h
v e h i c l e . Each p a n e l c a r r i e s 4 , 3 6 8 s o l a r c e l l s ( 2 x 2 e m , )
and p r o t e c t i v e g l a s s f i l t e r s t h a t r e d u c e t h e amount of
s o l a r r a d i a t i o n absorbed without i n t e r f e r i n g with t h e
e n e r g y c o n v e r s i o n . The c e l l modules a r e s u p p o r t e d b y
l i g h t w e i g h t p a n e l s t r u c t u r e s made o f t h i n - g a u g e aluminum,
Nominal power c a p a b i l i t y o f t h e p a n e l s i s e x p e c t e d
t o be 800 watts a t maximum power v o l t a g e f o r c r u i s e
c o n d i t i o n s i n s p a c e n e a r E a r t h . T h i s power c a p a b i l i t y
d e c r e a s e s t o a b o u t 500 watts a t t h e Mars d i s t a n c e i f
t h e r e i s no d e g r a d a t i o n b e c a u s e o f s o l a r f l a r e s . Max-
imum power demand i s e x p e c t e d t o b e l e s s t h a n 400 w a t t s
during o r b i t a l operations.
Minimum c a p a c i t y o f t h e s p a c e c r a f t b a t t e r y i s 600
w a t t h o u r s . The b a t t e r y w i l l b e c a p a b l e of d e l i v e r i n g
i t s r e q u i r e d c a p a c i t y and m e e t i n g a l l e l e c t r i c a l r e q u i r e -
m e n t s w i t h i n a n o p e r a t i o n a l t e m p e r a t u r e r a n g e o f 30 t o 90
degrees F a h r e n h e i t ( 1 0 t o 32 degrees C e l s i u s ) . A t
temperatures outside t h i s range, it w i l l s t i l l function
a l t h o u g h i t s c a p a b i l i t y w i l l be reduced.
- more -
To e n s u r e maximum r e l i a b i l i t y , t h e power s u b s y s t e n
was d e s i g n e d t o l i m i t t h e n e e d f o r b a t t e r y power a f t e r
i n i t i a l Sun a c q u i s i t i o n . E x c e p t d u r i n g m a n e u v e r s , t h e
b a t t e r y w i l l r e m a i n i d l e and f u l l y c h a r g e d . The b a t t e r y
charger w i l l provide a high-rate o r a t r i c k l e charge.
Under n o r m a l f l i g h t c o n d i t i o n s , t h e p r i m a r y power
booster-regulator w i l l handle a l l spacecraft loads, A
s e c o n d r e g u l a t o r w i l l s u p p o r t power l o a d s on a s t a n d - b y
b a s i s . Should an out-of-tolerance v o l t a g e c o n d i t i o n
e x i s t i n t h e main r e g u l a t o r , t h e s t a n d - b y r e g u l a t o r xi11
t a k e I t s p l a c e on t h e l i n e .
P r i m a r y f o r m o f power d i s t r i b u t e d t o o t h e r s p a c e -
c r a f t s y s t e m s i s 2,400 h e r t z s q u a r e wave. The g y r o s p i n
m o t o r s u s e 400 h e r t z t h r e e - p h a s e c u r r e n t , and t h e s c a n
m o t o r i s s u p p l i e d w i t h 400 h e r t z s i n g l e - p h a s e c u r r e n t ,
The t r a n s m i t t e r a m p l i f i e r t u b e , b a t t e r y c h a r g e r s and
t e m p e r a t u r e c o n t r o l h e a t e r s u s e u n r e g u l a t e d d c power
from t h e s o l a r p a n e l s o r t h e b a t t e r y .
A c r y s t a l o s c i l l a t o r i n t h e main power i n v e r t e r
c o n t r o l s t h e frequency t o w i t h i n 0 . O l p e r c e n t , a s s u r i n g
o t h e r s p a c e c r a f t systems of a r e l i a b l e , a c c u r a t e fre$uency
on t h e i r power l i n e . A backup c r y s t a l o s c i l l a t o r i s l o c a t e d
i n t h e s t a n d - b y i n v e r t e r . The s p a c e c r a f t C e n t r a l Computer
and Sequencer u s e s t h e o s c i l l a t o r frequency a s a timing
source.
Telemetry measurements have been s e l e c t e d t o p r o v i d e
t h e n e c e s s a r y i n f o r m a t i o n f o r t h e management o f s p a c e c r a f t
power l o a d s by ground command i f n e c e s s a r y .
Temperature Control
F o r a s p a c e c r a f t t r a v e l i n g t o Mars, away froin E a r c h and
f r o m t h e Sun, t h e p r i m a r y t e m p e r a t u r e c o n t r o l p r o b l e m i s
maintaining temperatures within allowable l i m i t s despite the
d e c r e a s i n g s o l a r i n t e n s i t y as t h e m i s s i o n p r o g r e s s e s , I n
a i r l e s s s p a c e , t h e t e m p e r a t u r e d i f f e r e n t i a l between t h e s u n l i t
s i d e and t h e s h a d e d s i d e o f a n o b j e c t c a n b e s e v e r a l h u n d r e d
degrees.
- more -
H e a t i n g by d i r e c t s u n l i g h t on t h e M a r i n e r s p a c e c r a f t
i s m i n i m i z e d by t h e u s e o f a t h e r m a l b l a n k e t on i t s Sun
s i d e . The s i d e away f r o m t h e Sun i s c o v e r e d w i t h a t h e r m a l
blanket TO prevent r a p i d l o s s of h e a t t o t h e c o l d of s p a c e ,
The t o p o f M a r i n e r ' s b a s i c o c t a g o n and t h e p r o p d l s i o n
module a r e i n s u l a t e d f r o m t h e Sun by a m u l t i - l a y e r e d s h i e l d
o f a l u m i n i z e d T e f l o n . The o u t e r l a y e r o f t h e s h i e l d , con-
s t r u c t e d of a t i g h t l y - w o v e n f i b e r g l a s s c l o t h , a l s o s e r v e s
as a f o i l a g a i n s t m i c r o m e t e o r o i d s . The b o t t o m i s e n c l o s e d
by a n o t h e r m u l t i - l a y e r e d b l a n k e t t o r e t a i n h e a t g e n e r a t e d
by power c o n s u m p t i o n w i t h i n t h e s p a c e c r a f t .
T e m p e r a t u r e c o n t r o l o f s i x of t h e e l e c t r o n i c s compart-
ments i s p r o v i d e d by p o l i s h e d m e t a l l o u v e r s a c t u a t e d b y
c o i l e d b i m e t a l l i c s t r i p s . The s t r i p s a c t as s p i r a l - w o u n d
s p r i n g s t h a t expand and c o n t r a c t a s t h e y h e a t and c o o l .
T h i s m e c h a n i c a l a c t i o n , w h i c h opens and c l o s e s t h e l o u v e r s ,
i s c a l i b r a t e d t o p r o v i d e an o p e r a t i n g r a n g e from f u l l y c lo s e d
a t 55 d e g r e e s F a h r e n h e i t ( 1 3 d e g r e e s C e l s i u s ) t o f u l l y open
a t 90 d e g r e e s F a h r e n h e i t ( 3 2 d e g r e e s C e l s i u s ) . A l o u v e r
assembly c o n s i s t s of 22 h o r i z o n t a l l o u v e r s d r i v e n i n p a i r s
by 11 a c t u a t o r s . Each p a i r o p e r a t e s i n d e p e n d e n t l y 011 i t s
own l o c a l t e m p e r a t u r e d e t e r m i n e d by i n t e r n a l power d i s s i p a t i o n ,
The s c i e n c e p l a t f o r m and i t s a r r a y o f i n s t r u r n e n ~ sa t t h e
b o t t o m o f t h e o c t a g o n a r e c o v e r e d by a t h i r d t h e r m a l b l a n k e t ,
The p l a t f o r m i s d e s i g n e d t o b e t h e r m a l l y i s o l a t e d from t h e
main equipment o c t a g o n by a p l a s t i c c o l l a r on t h e a t t a c h i n g
s u p p o r t t u b e . T e m p e r a t u r e c o n t r o l i s a c h i e v e d by e l e c t r 5 c a l
d i s s i p a t i o n i n h e a t e r s and i n t h e i n s t r u m e n t s t h e m s e l v e s ,
Electric heaters are located within the science platforn
b l a n k e t , i n t h e p r o p u l s i o n module and i n two o f t h e e l e c t r o n i c s
bays t o provide a d d i t i o n a l h e a t d u r i n g c e r t a i n p o r t i o n s of t h e
mission.
P a i n t p a t t e r n s a n d p o l i s h e d m e t a l s u r f a c e s a r e used. on
t h e Mariner f o r p a s s i v e c o n t r o l of temperatures o u t s i d e of t h e
p r o t e c t e d o c t a g o n and c o v e r e d s c i e n c e p l a t f o r m . T h e s e s u r f a c e s
c o n t r o l b o t h t h e amount of h e a t d i s s i p a t e d i n t o s p a c e a n a t h e
amount o f s o l a r h e a t a b s o r b e d o r r e f l e c t e d away. The p a t t e r n s
were d e t e r m i n e d f r o m t e s t i n g a T e m p e r a t u r e C o n t r o l Model (TCPl)
o f t h e s p a c e c r a f t i n a s p a c e s i m u l a t i o n chamber a t J P L and
from t h e a p p l i c a t i o n o f a c t u a l m i s s i o n d a t a a c q u i r e d d u r i c g
t h e M a r i n e r 4 (1964-65) and t h e M a r i n e r 6 and 7 ( 1 9 6 9 ) m i s s i o n s
t o Mars.
- more -
The h i g h - g a i n a n t e n n a d i s h , which i s d e p e n d e n t upon t h e
Sun f o r i t s s u r f a c e h e a t , i s p a i n t e d g r e e n t o k e e p i t a t n e a r
room t e m p e r a t u r e a t t h e Mars d i s t a n c e b u t w i t h i n i t s u p p e r
thermal l i m i t e a r l i e r i n t h e mission.
Scan P l a t f o r m
M a r i n e r ' s s c i e n c e i n s t r u m e n t s a r e mounted on a s c a n p l a t -
f o r m which c a n b e r o t a t e d a b o u t two a x e s t o p o i n t t h e i n s t r u m e n t s
t o w a r d Mars d u r i n g t h e s p a c e c r a f t ' s a p p r o a c h t o t h e p l a n e t and
w h i l e i n o r b i t . The p l a t f o r m i s l o c a t e d below t h e o c t a g o n a l
base of t h e s p a c e c r a f t .
The s c a n c o n t r o l s y s t e m a l l o w s m u l t i p l e p o i n t i n g d i r e c t i o n s
o f t h e i n s t r u m e n t s a s t h e o r b i t p h a s e of t h e m i s s i o n p r o g r e s s e s ,
The p l a t f o r m ' s two a x e s of r o t a t i o n a r e d e s c r i b e d as t h e c l o c k
a n g l e m o t i o n a b o u t t h e a x i s o f t h e t u b e e x t e n d i n g vertically
from t h e o c t a g o n and cone a n g l e m o t i o n a b o u t a n a x i s which i s
horizontal.
- more -
SCIENTIFIC EXPERIMENTS
Mars i s a c o n s t a n t l y c h a n g i n g w o r l d w i t h s e a s o n a l
and d a i l y v a r i a t i o n s t h a t have been observed w i t h
d i f f i c u l t y f r o m E a r t h a n d o n l y b r i e f l y by f l y b y s p a c e -
craft.
I n t h i s o r b i t i n g m i s s i o n a b a t t e r y of i n s t r u m e n t s
w i l l p r o b e t h e p l a n e t on a d a i l y b a s i s f o r t h r e e m o n t h s
and p o s s i b l y l o n g e r .
The s u r f a c e w i l l b e e x a m i n e d by p h o t o g r a p h y a n d i n
t h e i n f r a r e d w a v e l e n g t h s . The a t m o s p h e r e w i l l b e e x a m i n e d
i n t h e u l t r a v i o l e t a n d i n f r a r e d a n d by t h e o c c u l t a t i o n
experiment.
From t h e t o p o f t h e t h i n M a r t i a n g a s e n v e l o p e down
t o t h e s u r f a c e and t h e i n t e r i o r of c r a t e r s , t h e a t m o s p h e r i e
instruments w i l l record data t o identify gases, plot the
m i x t u r e of c o n s t i t u e n t s and v a r i a t i o n s r e l a t i v e t o t i m e and
area.
The i n s t r u m e n t s w i l l v i e w a n e a r l y w i n t e r a t m o s p h e r e
a n d s u r f a c e i n t h e N o r t h a n d e a r l y summer i n t h e S o u t h ,
The i n f o r m a t i o n g a t h e r e d s h o u l d p r o v i d e a b r o a d
p i c t u r e of t h e f a c t o r s t h a t shape physical processes a t
work on Mars. The q u e s t i o n s t o b e a n s w e r e d r a n g e f r o m
d a i l y weather p a t t e r n s t o t h e h i s t o r y of t h e formation of
the planet.
The c u t t i n g e d g e o f t h i s m i s s i o n i s n o t o n l y r i l e
o p p o r t u n i t y t o e x a m i n e Mars i n d e t a i l on a d a i l y b a s i s j u t
i s a l s o t h e c a r e f u l l y p l a n n e d c o r r e l a t i o n o f d a t a fro-n rhe
i n s t r u m e n t s t o y i e l d more t h a n t h e sum t o t a l o f t h e p a r % s ,
- more -
A p h o t o g r a p h c a n b e c o r r e l a t e d w i t h t e m p e r a t u r e s on
t h e s u r f a c e and t h e p r e s s u r e a n d c o n s t i t u e n t s o f t h e a 5mos-
I
p h e r e above t h e a r e a p h o t o g r a p h e d . A p h y s i c a l f e a t u r e on t h e
s u r f a c e can t h u s be r e l a t e d t o o t h e r d a t a o b t a i n e d ,
P a s t o b s e r v a t i o n s h a v e e s t a b l i s h e d t h e p r e s e n c e of c i a ~ d s ,
h a z e s , b r i g h t s p o t s a n d f l a r e s o f l i g h t on t h e s u r f a c e , Yeliow
c l o u d s , t h o u g h t t o b e d u s t , c a n grow l a r g e enough t o o b s c u r e a
l a r g e p o r t i o n o f t h e f a c e o f Mars a n d l a s t a month o r two,
White c l o u d s r a n g e from a h a z e , l a s t i n g a few h o u r s , t o huge
d e n s e c l o u d s p e r s i s t i n g f o r d a y s o r weeks. Dark g r a y c l o u d s
h a v e b e e n r e p o r t e d and t h o u g h t t o p o s s i b l y b e v o l c a n i c i n
o r i g i n . F o u r were r e p o r t e d i n 1950 and 1 9 5 2 . F l a r e s s e e n
on t h e s u r f a c e have a l s o been a t t r i b u t e d t o p o s s i b l e v s l c a n l c
activity.
S t u d y o f t h e s e phenomena by t h e combined i n s t r u m e n t
package i s an o b j e c t i v e o f t h e m i s s i o n .
Another s p e c i f i c s c i e n t i f i c o b j e c t i v e i s a s t u d y o f t h e
"wave o f d a r k e n i n g " . O b se r v a t i o n s from E a r t h have e s t a b l i s h e d
t h a t t h e r e i s a s e a s o n a l d a r k e n i n g of f e a t u r e s on Mars b u t i f
i t p r o g r e s s e s a t a r e g u l a r r a t e , i n a waveform i s , t o d a y , open
t o question.
The s p a c e c r a f t w i l l a r r i v e a t Mars a t t h e p e ~ kof t h e
darkening p e r i o d i n t h e s o u t h e r n hemisphere. It will be
o b s e r v e d a t i t s maximum i n t e n s i t y a n d c a n b e compared w i t h
observations i n t h e n o r t h e r n hemisphere.
The w a t e r c o n t e n t o f t h e M a r t i a n a t m o s p h e r e i s known
t o be e x t r e m e l y low, s i m i l i a r t o t h e d r y A n t a r c t i c , But
i t i s p o s s i b l e t h a t f r e e w a t e r was f r o z e n i n t h e p a s t and
r e m a i n s u n d e r t h e s u r f a c e l i k e p e r m a f r o s t . Heat e s c a p l n g
from t h e i n t e r i o r o f Mars c o u l d m e l t t h e i c e and p r o v i d e
a w a t e r s o u r c e f o r o r g a n i s m s . ' I f s o , s u c h a n a r e a would
be a prime t a r g e t f o r t h e Vfking l a n d e r t h a t w i l l seek
e v i d e n c e o f l i f e on Mars i n 1 9 7 6 .
I n t h e low p r e s s u r e of t h e M a r t i a n a t m o s p h e r e , h o w e v e r ,
water can only e x i s t i n a f r o z e n o r vaporous s t a t e w i t h perhaps
a s h o r t - l i v e d i n t e r m e d i a t e s t a t e t h a t c o u l d m o i s t e n t h e scil,
I n t h e e v e n t o f underground i c e m e l t i n g t h e r e i s , t h e n , a
p o s s i b i l i t y o f a c l o u d forming o v e r t h e a r e a . Photography o f
s u c h a c l o u d c o r r e l a t e d w i t h w a t e r v a p o r and t e m p e r a t u r e
measurements could i n d i c a t e an a r e a a c c e p t a b l e f o r l i f e forms.
- more -
The mapping o f Mars i n t h i s n i s s i o n i s a b a s i c objective.
It i s e s s e n t i a l i n t h e s t u d y o f a p l a n e t t o e s t a b l i s h a t h r e e
dimensional shape of t h e p l a n e t , t h e f i g u r e . A p e r s i s t e n t
d i s c r e p a n c y , however, e x i s t s b e t w e e n o p t i c a l o b s e r v a t i o n s
f r o m E a r t h and d a t a d e r i v e d f r o m t h e o r b i t s o f t h e t ~ moons o
o f Mars and s p a c e c r a f t f l y b y t r a j e c t o r i e s .
S t u d i e s o f t h e ' 7 1 d a t a may r e s o l v e t h a t q u e s t i o n and
w i l l e s t a b l i s h t h e Martian geoid, a standard sphe-ical refer-
e n c e s u r f a c e f o r mapping. On E a r t h , t h e g e o i d c o i n c i d e s w i t h
mean s e a l e v e l i n t h e o c e a n s .
D i s c r e p a n c i e s o f f i v e t o 1 0 d e g r e e s i n l a t i t u d e acd
l o n g i t u d e , 180 t o 380 m i l e s ( 2 9 0 t o 6 1 0 k i l o m e t e r s ) az t h e
s u r f a c e , a r e n o t uncommon b e t w e e n v a r i o u s p u b l i s h e d maps o f
Mars. A r e c e n t l y c o m p l e t e d 1 0 - y e a r Mars Map P r o j e c t , k g
d e V a u c o u l e u r s , u s i n g a l l E a r t h - b a s e d v i s u a l and p h o t o g r a p h i c
d a t a f r o m 1 8 7 7 t o 1 9 5 8 may h a v e r e d u c e d e r r o r s t o a b o u t one
d e g r e e , o r 3 1 m i l e s ( 5 0 k i l o m e t e r s ) i n r e g i o n s where weli-
d e f i n e d s u r f a c e markings ( i . e . , albedo v a r i a t i o n s ) a r e
a v a i l a b l e . One o f t h e m a j o r mapping a p p l i c a t i o n s o f t h e
w i d e - a n g l e camera p h o t o g r a p h y w i l l b e t o p r e c i s e l y l o c a t e
s u r f a c e markings t o a r e s o l u t i o n o f a p p r o x i m a t e l y one m i l e
(1.6 kilometers).
Television
The t e l e v i s i o n e x p e r i m e n t w i l l p r o v i d e f o r M i s s i o n A ,
a map o f 70 p e r c e n t o f Mars a t medium r e s o l u t i o n and d e t a i l e d
s t u d i e s of 5 p e r c e n t o f t h e s u r f a c e a t h i g h r e s o l u t i o n , M a r i n e r
4 i n 1965 photographed 1 p e r c e n t of t h e s u r f a c e , and M a r i n e r s
6 and 7 i n 1 9 6 9 , 1 0 p e r c e n t .
The w i d e - a n g l e c a m e r a s w i l l r e s o l v e f e a t u r e s on t h e
s u r f a c e a b o u t 3,280 f e e t ( 1 , 0 0 0 m e t e r s ) i n l e n g t h , Narrow-
a n g l e c a m e r a s w i l l r e s o l v e f e a t u r e s a b o u t 328 f e e t ( 1 C C m e t e r s )
i n length.
The a d v a n t a g e s o f a n o r b i t i n g m i s s i o n w i l l b e e x p l o i t e d
f o r Mission B i n r e p e a t e d photographic s t u d i e s of i n d i v i d u a l
a r e a s o v e r a p e r i o d o f t i m e t o d e t e c t c h a n g e s on t h e s u r f a c e
and i n t h e atmosphere.
S p e c i f i c a r e a s o f s t u d y a r e t h e "wave o f d a r k e n i n g f Y
( s e a s o n a l s u r f a c e c o l o r c h a n g e ) , p o l a r caps and t h e p o l a r
cap-edge, a t m o s p h e r i c and s u r f a c e f l u o r e s c e n c e , a t m o s p h e r ic
h a z e , b l u e c l e a r i n g s , w h i t e and y e l l o w c l o u d s and c l o u d
movements.
- more -
-34-
LENS
MOLDER LENS COVER ASShhdBLV
(I
----D
CIRCUIT
SPACER
VIDICON FACE--
M G N E I I C SHIELD-/
)----CAMEM
MOUMBiNG
SU RFAC E
CWEM HEAD
A l t h o u g h n o t a p r i m a r y o b j e c t i v e , t h e two moon: oi
Mars, Phobos a n d Diemos, may be p h o t o g r a p h e d t o o b t a i n
i n f o r m a t i o n on t h e i r s h a p e , s i z e and s u r f a c e f e a t u r e s ,
P r e l a u n c h s t u d i e s i n d i c a t e t h a t t h e s p a c e c r a f t s w i l l zo171
w i t h i n s u f f i c i e n t p r o x i m i t y o f t h e moons t o o b t a i n surfac?
data.
P r i o r t o i n s e r t i o n i n t o o r b i t , t h e n a r r o w camera: <$-I1
p r o v i d e a p p r o a c h p h o t o g r a p h s o f Mars s i m i l a r t o t h e s e r i e s
t a k e n i n 1 9 6 9 by M a r i n e r s 6 a.nd 7. The s e q u e n c e s v : j l l ~ e g i q
a t r a n g e s i n e x c e s s o f one m i l l i o n m l l e s (1,609,OOQ k i l c r 3 e r ; e r z ;
f r o m Mars.
It w i l l b e e a r l y w i n t e r i n Marsr n o r t h e r n h e m i s p h e r e
on a r r i v a l and e a r l y summer i n t h e s o u t h e r n h e m i s p h e r e ,
T h i s i s s i m i l a r t o t e l e s c o p e o b s e r v a t i o n s made i n 1958 a t
Mars o p p o s i t i o n .
The TV e x p e r i m e n t on M a r i n e r H ( M i s s i o n A ) w i l l , LP
mapping t h e s u r f a c e , p r o v i d e a wide r a n g e of i n f o r n a t i o l -
f o r s t u d i e s o f b r i g h t and d a r k r e g i o n s : f i n e S ~ ~ U ~ T I c- J ' Y ~
t o p o g r a p h i c d e t a i l s , a n d s u c h p r o c e s s e s as v o l c a n i s n ,
t e c t o n i s m , i m p a c t , e r o s i o n and a t m o s p h e r i c a c t i v i t y ,
The o b j e c t i v e s a l s o i n c l u d e :
- A d e t e r m i n a t i o n of t h e s h a p e of t h e p l a n e t , ( D a t a
f r o m t r a j e c t o r i e s o f f l y b y s p a c e c r a f t and t h e o r b i t s o f %he
two M a r t i a n moons do n o t a g r e e w i t h E a r t h - b a s e d o b s e r v a t i o n .
- High p r e c i s i o n g e o d e t i c c o o r d i n a t e s o f a l a r g e n u ~ l h e r
o f w e l l d e f i n e d t o p o g r a p h i c f e a t u r e s f o r maps o f TI-e o l a r e r ; ,
- To i n v e s t i g a t e , by p h o t o m e t r i c and p h o t o g r a m ~ ec r ; ~
a n a l y s i s , s u r f a c e s l o p e s and r e l a t i v e e l e v a t i o n characJ;er-
i s t i c s ; t o d e t e r m i n e s u r f a c e b r i g h t n e s s and a l b e d o d i C f c r ~ n c e r ;
and t o p e r f o r m a n a l y s e s r e l a t e d t o i m p r o v i n g t h e a e c u r d c j o f
t h e p h o t o m e t r i c f u n c t i o n of Mars.
- more -
It is evident from Earth-based radar data that albedo
(amount and spectrum of reflected light) and elevation
differences on Mars do not have a close correlation. Zetailed
studies of this fact may have great significance for an inter-
pretation of observed albedo variations.
Mariner I (Mission B) will study time-variable features
on the surface and in the atmosphere of Mars in order to obcain
information on the atmospheric structure and circulation, details
of diurnal and seasonal changes, and clues regarding the pos-
sibility of life on Mars. The specific areas to be stxdied are
wave of darkening, polar caps and cap adjacent areas, nightslde
atmospheric and surface fluorescence, haze in the atmosphere,
white clouds and patches at low latitudes, yellow c1ou.a~and
storms and the Martian satellites to obtain inforrnatiolz o n
their shape and surface features.
Each wide-angle camera is equipped with comnandable
filters allowing a choice of eight filters.
The team leader is Harold Mazursky, U. S. Geological
Survey, Flagstaff, AZ. Other principal investigators are
Bradford Smith, New Mexico State University; Dr. Joshua
Lederberg, Stanford University; Dr. Gerard de Vaucouleurs,
University of Texas; and Dr. Geoffrey A. Briggs, Belleom,
Infrared Radiometer (IRR)
This experiment will provide temperature measurements
of the surface of Mars by detection of thermal radiation
in the infrared portion of the electromagnetic spectrum,
The,instrument is boresighted with the television
cameras to allow correlation of surface temperatures
terrain features and clouds.
The thermophysical properties of the surface will he
mapped during the length of the standard missions.
Irregularities in diurnal cooling curves will b e compared
to photographs for similarity of areas to visible albedo
variation. Existence of "hot spots", which are slightly
high average temperature areas, will be studied for
indications of internal heat sources.
- more -
MARINER INFR ED RADIOMETER
(TO MEASURE MARS SURFACE TEMPERATURES)
FOCUSING LENS
FOCUSING LENS
O b s e r v a t i o n s from Ma r i n e r ' 7 1 w i l l p r o v i d e c o o l i n g
curves c h a r a c t e r i s t i c of i n d i v i d u a l a r e a s ; t h u s , t h e degree
o f c o r r e l a t i o n t h a t may e x i s t b e t w e e n c h a r a c t e r i s t i c c o o l i n g
c u r v e s and m a j o r p h y s i o g r a p h i c f e a t u r e s c a n be f o u n d ,
E s s e n t i a l l y t h e same i n s t r u m e n t f l o w n on t h i s m i s s i o n
was f l o w n on t h e 1 9 6 9 m i s s i o n t o Mars b u t viewed o n l y o n e
p e r c e n t of t h e s u r f a c e . I n t h e o r b i t i n g mission it i s
e x p e c t e d t h a t as much as 2 0 p e r c e n t o f t h e s u r f a c e w i l l
be c o v e r e d .
The w i d e r c o v e r a g e i s e x p e c t e d t o d e t e r m i n e a c c u r a t e l y
t h e thermophysical p r o p e r t i e s of s u r f a c e f e a t u r e s .
The p r i n c i p a l i n v e s t i g a t o r i s D r . G e r r y Neugebauer of
t h e C a l i f o r n i a I n s t i t u t e of T e c h n o l o g y .
U l t r a v i o l e t Spectrometer
The o b j e c t i v e s o f t h i s e x p e r i m e n t a r e t o map t h e s u r f a c e
and l o w e r a t m o s p h e r e i n u l t r a v i o l e t ( u l t r a v i o l e t c a r t o g r a p h y )
and t o s t u d y t h e t e m p e r a t u r e a n d s t r u c t u r e i n t h e uppel-
atmosphere ( u l t r a v i o l e t aeronomy).
The e x p e r i m e n t w i l l m e a s u r e : l o c a l atmospheric
p r e s s u r e s which c a n b e r e l a t e d t o e l e v a t i o n s o v e r a m a j o r
p a r t o f Mars; l o c a l c o n c e n t r a t i o n s o f o z o n e ; r e f l e c t a b i l i t ; ]
of t h e M a r t i a n s u r f a c e i n t h e n e a r - u l t r a v i o l e t and p r o v i d e
UV s t u d i e s o f t h e "wave of d a r k e n i n g " c l o u d s and t h e b l u e
haze-blue c l e a r i n g .
D e t e c t i o n o f ozone c o u l d y i e l d c l u e s a s t o tile p o s s i i l h y
o f l i f e forms on Mars. B i o l o g i c a l a c t i v i t i e s c a n prodrxce
m o l e c u l a r oxygen which c a n l e a d t o t h e f o r m a t i o n of ozone. I f
t h e measurement o f ozone i s a t h i g h enough l e v e l s , t h e L i t h e
p o s s i b i l i t y e x i s t s t h a t l i f e may b e p r e s e n t . T h i s l e v e l nourd
h a v e t o e x c e e d what c o u l d be e x p l a i n e d by o t h e r n o n - b i o l o g i c a l
processes. F i n a l d e t e r m i n a t i o n o f t h e l i f e q u e s t i o n , r,c:ever,
w i l l depend on a l a n d e d s y s t e m w i t h measurements t a k e n a: the
surface.
- more -
MARINER ULTRAVIOLET SPECTROMETER
MIRROR FOCUSES
SEPARATED WAVE-
LENGTHS OF LIGHT
ON EXIT SLITS
1. -
MIRROR REFLECTS
LIGHT IN
PARALLEL BEAMS
P r i n c i p a l i n v e s t i g a t o r f o r t h i s e x p e r i ~ n e n ti s D r . C h a r l e s
Barth of t h e U n i v e r s i t y of Colorado.
I n f r a r e d Interferometer Spectrometer (IRIS)
T h i s experiment w i l l measure r a d i a t i o n i n i n f r a r e d
w a v e l e n g t h s f r o m t h e s u r f a c e and a t m o s p h e r e of Mars t o
p r o v i d e i n f o r m a t i o n on a wide r a n g e of p h y s i c a l c h a r a c t e r i s t i c s
o f Mars.
I n g e n e r a l , t h e d a t a w i l l p r o v i d e a p i c t u r e of t h e c i r -
c u l a t i o n o f t h e a t m o s p h e r e and c o m p o s i t i o n o f t h e s u r f a c e .
I n d e t a i l t h e experiment i s expected t o y i e l d c o n s t i t u e n t s
o f t h e a t m o s p h e r e , i n c l u d i n g t h e i m p o r t a n t measurement o f t h e
amount o f w a t e r v a p o r ; t e m p e r a t u r e s a n d p r e s s u r e s a t t h e
s u r f a c e , t e m p e r a t u r e p r o f i l e of t h e a t m o s p h e r e , m a t e r i a l s on
t h e s u r f a c e , a n d d e t e r m i n a t i o n of t h e c o m p o s i t i o n of t h e p o l a r
c a p s , f r o z e n c a r b o n d i o x i d e , f r o z e n w a t e r o r a m i x t u r e of ' b o t h ,
A l t h o u g h a t m o s p h e r i c and s u r f a c e d a t a w i l l p r o v i d e a b a s i s
f o r b i o l o g i c a l i n f e r e n c e s , t h e q u e s t i o n o f l i f e on Mars w i l l
o n l y b e r e s o l v e d when a l a n d e d s y s t e m c a n t a k e m e a s u r e m e n t s a t
the surface.
The p r i n c i p a l i n v e s t i g a t o r i s D r . Rudolph H a n e l , Goddard
Space F l i g h t Center.
S-Band O c c u l t a t i o n E x p e r i m e n t
T h i s e x p e r i m e n t h a s b e e n s u c c e s s f u l l y p e r f o r m e d by f l y b y
s p a c e c r a f t a t Venus i n 1 9 6 7 a n d a t Mars i n 1 9 6 5 and 1 9 6 9 . The
two l a t t e r m i s s i o n s y i e l d e d t h r e e p a i r s of o c c u l t a t i o n measure-
m e n t s . The ' 7 1 o r b i t i n g m i s s i o n w i l l p r o v i d e up t o 1 0 0 p a i r s
f r o m t h e two s p a c e c r a f t i n t h e 90-day m i s s i o n s . A p a i r i c c l u d e s
m e a s u r e m e n t s when t h e s p a c e c r a f t d i s a p p e a r s b e h i n d t h e p l a n e t
and r e a p p e a r s .
- more -
MARINER INFRARED INTERFEROMETER SPECTROMETER
(TO MEASURE GASES, PARTICLES, TEMPERATURES ON AND ABOVE MARS SURFACE)
3-POSITION MIRROR
PERISCOPE
/ SPACE VIEW PORT
ELECTRONICS CONVERTS
DETECTOR CURRENT TO
PULSES FOR RADIO
MESSAGE CODING
MOTOR
COLLECTOR MIRROR
/ SEMI-TRANSPARENT
BEAMSPLITTER
This experiment u t i l i z e s t h e r a d i o s i g n a l s t r a n s m i t t e d
from t h e s p a c e c r a f t t o E a r t h and d o e s n o t r e q u i r e on-board
equipment. It dozs r e q u i r e an o r b i t a l p a t h t h a t p a s s e s
b e h i n d Mars a s s e e n f r o m E a r t h , t h u s o c c u l t i n g t h e s p a e e -
c r a f t f r o m t h e view o f t r a c k i n g s t a t i o n s .
A s t h e s p a c e c r a f t c u r v e s b e h i n d Mars, i t s r a d i c
s i g n a l w i l l p a s s t h r o u g h t h e M a r t i a n atmospflere and be
cut off at the surface. The s i g n a l w i l l r e a p p e a r a s t h e
s p a c e c r a f t comes o u t f r o m b e h i n d t h e p l a n e t and a g a i n t h e
r a d i o s i g n a l w i l l pass through t h e p l a n e t ' s atmosphere.
The a t m o s p h e r e w i l l r e f r a c t t h e r a d i o waves, c h a n g i n g
them i n f r e q u e n c y and s t r e n g t h . Measurements on E a r t h of
t h e s e c h a n g e s i n t h e r a d i o s i g n a l y i e l d t h e d a t a on t h e
d e n s i t y and p r e s s u r e o f t h e a t m o s p h e r e .
S i m i l a r c h a n g e s i n t h e a t m o s p h e r e o f Mars a r e c a u s e d
by e l e c t r o ~d e n s i t y and a r e a l s o m e a s u r e a b l e .
The c u t t i n g o f f o f t h e s i g n a l a t t h e s u r f a c e and
r e s u m p t i o n of t h e s i g n a l as t h e s p a c e c r a f t comes o u t from
b e h i n d t h e p l a n e t Mars, p r o v i d e s d a t a f o r c a l c u l a t i o n c f
t h e r a d i u s and s h a p e o f Mars.
D e t e r m i n a t i o n o f t h e a t m o s p h e r i c d e n s i t y o f Mars i s
v i t a l t o t h e d e s i g n o f f u t u r e l a n d i n g c r a f t ,-and i s a
c r i t i c a l f a c t o r i n t h e r e s o l u t i o n of i m p o r t a n t s c i e n t i f i c
q u e s t i o n s on t h e n a t u r e o f t h e p l a n e t .
The p r i n c i p a l i n v e s t i g a t o r i s D r . Arvydas K l i o r e o f
JPL.
C e l e s t i a l Mechanics
R a d i o t r a c k i n g o f two o r b i t i n g s p a c e c r a f t o v e r a p e r i o d
o f t i m e i s e x p e c t e d t o p r o v i d e a more a c c u r a t e d e s c r i p t i o n
of t h e M a r t i a n g r a v i t y f i e l d t h a n p r o v i d e d by t h e o r b i t s o f
t h e two moons of Mars and r e f i n e m e n t of t h e a s t r o n o m i c a l unit
( t h e d i s t a n c e from t h e Sun t o E a r t h , a b a s i c a s t r o n o m i c a l y a r d
s t i c k ) t o a f r a c t i o n of a m i l e . T h i s a c c u r a c y o f t h e expected
AU r e f i n e m e n t i s u n p r e c e d e n t e d .
- more -
T h i s e x p e r i m e n t d e r i v e s i t s r e s u l t s from s p a c e c r a f t
t r a c k i n g i n f o r m a t i o n and d o e s n o t r e q u i r e s p e c i a l h a r d w ~ ~ r e
on t h e s p a c e c r a f t .
The o b j e c t i v e s o f t h e e x p e r i m e n t i n c l u d e s measllre~-.ier:ts
o f t h e mass o f Mars; t h e Earth-Moon mass r a t i o and ':he a i s t a n c e
f r o m E a r t h t o Mars. Long-range o b j e c t i v e s a r e t o o b t a i n a n
improved e p h e m e r i s o f Mars ( i t s p o s i t i o n a t g i v e n tires i n ~ t s
s o l a r o r b i t ) t o a h i g h o r d e r o f a c c u r a c y and t o a t t e m p t co
m e a s u r e G e n e r a l R e l a t i v i s t i c e f f e c t s on o r b i t a l m o t i o n s a n d
s i g n a l propagation.
I m p r o v i n g t h e e p h e m e r i s o f Mars i s p a r t of a n exisc9i:p
NASA/JFL p r o j e c $ t o improve t h e e p h e m e r i d e s o f a l l she inne--
planets. The M a r i n e r t r a c k i n g d a t a w i l l b e combined witr
r a d a r and o p t i c a l t e l e s c o p e d a t a t o a c h i e v e t h e r e s u l t s ,
- more -
MARINER MARS
-- 1971 SCIENCE EXPERIMENTS AND INVESTIGATORS
Television
Harold Masursky-Team Leader U. S. Geological Survey E 2 i r - c i pal
I~vestigat3..~
7
Dr. Gerard de Vaucouleurs University of Texas
11
Dr. Geoffrey A, Briggs Bellcom
- more -
T e l e v i s i o n ( c o n t 'd)
Technology
D r . Bruce C . Murray C a l i f o r n i a I n s t i t u t e of I
Technology
D r . R o b e r t P. S h a r p 7s
I n f r a r e d Interferometer Spectrometer
D r . W. A. Hovis
V i r g i l Kunde
I!
Dr. G i l b e r t V . Levin
II
Dr. P . D . Lowman
Dr. Cuddapah P r a b h a k a r a
Benjamin Schlachrnan
I n f r a r e d Radiometer
D r . Hugh K . K i e f f e r U n i v e r s i t y of C a l i f o r n i a !I
a t Los Angeles
- more -
I n f r a r e d Radiometer ( c o n t ' d )
U l t r a v i o l e t Spectrometer
C e l e s t i a l Mechanics
D r . J o h n D . Anderson 11 Co-Investigator
Warren L. M a r t i n 11 II
S-Band O c c u l t a t i o n
Dan L . C a i n II Co-Investigator
Dr. Gunner F j e l d b o 11 1F
D r . S. I . Rasool Goddard I n s t i t u t e of S p a c e ~t
Studies
B o r i s L. S e i d e l J e t Propulsion Laboratory g
- more -
ATLAS-CENTAUR LAUNCH VEHICLE
The a b i l i t y o f t h e A t l a s - C e n t a u r t o l a u n c h t h e much
g r e a t e r weight o f t h e M a r i n e r H and I s p a c e c r a f t , a p p r a x i > ~ a t e l g
2,200 pounds (998 k i l o g r a m s ) compared w i t h t h e 850-pound
(385-kilogram) w e i g h t o f M a r i n e r s 6 and 7 , i s due p r i m a r i l y
t o t h e more f a v o r a b l e p o s i t i o n o f t h e p l a n e t Mars i n relat3.cn
t o t h e E a r t h t h i s y e a r . Such a f a v o r a b l e a l i g n m e n t GE tl?e
two p l a n e t s w i l l n o t o c c u r a g a i n u n t i l t h e 1 9 8 o y s .
Height: 75 f e e t ( 2 2 . 9 4 8 f e e t ( 1 4 - 6 meters)
meters) (including (with payload f a i r i n g )
interstage adapter)
* M e a s u r e d a t two i n c h e s ( 5 . 0 8 c e n t i m e t e r s ) o f r i s e
* * W e i g h t s a r e b a s e d o n AC-23 c o n f i g u r a t i o n . AC-24 v a r i e s
only s l i g h t l y .
r a,
od c
ri rl
5 53 fa
mil r:
E: a M
hi c
ad k
r:
c 0.t mk M6
0 Fak
m c rl 0 s 0
Ti 0 ad* cd*
4J-d 4P 5 4P s
-0- moo E:o
mu 5 mu
% m w
a, m
Ma,
hi Z: ri
'3 .d
,
:
4
K Z
a) @
0 C) Cd
I '3.3
=+C) C\i
a, kcdo in
0 3-C,
ca, mV)
3
0' m
a, k
V) a,
-C,
53 a, w
i
: E
ho o m
.d r i a in
d .ri
a z
-
r i m m m. .
'3 ti\ 03
. .
m ri 0 b C n N Ll
m ~ oa m a m 3 LC
c1
F l i g h t Sequence
Atlas P h a s e
A f t e r l i f t o f f , AC-24 w i l l r i s e v e r t i c a l l y f o r a b o u t 15
seconds b e f o r e b e g i n ni n g i t s p i t c h program. Starting a t ~ w c
s e c o n d s a f t e r l i f t o f f a n d c o n t i n u i n g t o T+15 s e c o n d s , t h e
v e h i c l e w i l l r o l l t o t h e d e s i r e d f l i g h t azimuth.
A f t e r 148 s e c o n d s of f l i g h t , t h e b o o s t e r e n g i n e s a r e
s h u t down (EECO) and j e t t i s o n e d . BECO o c c u r s when a n
a c c e l e r a t i o n of 5 . 7 g P s i s s e n s e d by a c c e l e r o m e t e r s on
t h e C e n t a u r and t h e s i g n a l i s i s s u e d by t h e C e n t a u r g u i d a n c e
s y s t e m , The b o o s t e r p a c k a g e i s j e t t i s o n e d 3 . 1 s e c o n d s a f t e r
BECO, The Atlas s u s t a i n e r e n g i n e c o n t i n u e s t o b u r n f o r
a p p r o x i m a t e l y a n o t h e r m i n u t e a n d 43 s e c o n d s p r o p e l - l i n g t h e
v e h i c l e t o a n a l t i c u d e o f a b o u t 87 m i l e s ( 1 4 8 k i l o m e t e r s ) ,
a t t a i n i n g a s p e e d of 8 , 3 0 0 mph ( 3 , 7 1 0 m / s ) .
S u s t a i n e r e n g i n e c u t o f f (SECO) o c c u r s a t p r o p e l l a n t
depletion. C e n t a u r i n s u l t a t i o n p a n e l s and n o s e f a i r i n g
a r e j e t t i s o n e d p r i o r t o SECO.
Centaur Phase
A t f o u r m i n u t e s , 22 s e c o n d s i n t o t h e f l i g h t , t h e
C e n t a u r P s two RL-10 e n g i n e s i g n i t e f o r a p l a n n e d s e v e n -
m i n u t e 34-second b u r n . T h i s w i l l p l a c e Centaur and t h e
s p a e e c r a f t on a n i n t e r p l a n e t a r y t r a j e c t o r y a t a s p e e d o f
a b o u t 24,714 mph ( 1 1 , 0 5 0 m / s ) . A f t e r MECO, t h e C e n t a u r
s t a g e and s p a c e c r a f t a r e r e o r i e n t e d w i t h t h e Centaur
a t t i t u d e c o n t r o l t h r u s t e r s t o p l a c e t h e s p a c e c r a f t on
the proper t r a j e c t o r y a f t e r separation.
S e p a r a t i o n of t h e Mariner s p a c e c r a f t i s achieved by
f i r i n g e x p l o s i v e b o l t s on a V-shaped m e t a l band h o l d i n g
t h e s p a c e c r a f t t o t h e a d a p t e r , Compressed s p r i n g s then.
p u s h t h e s p a e e c r a f t away f r o m t h e C e n t a u r v e h i c l e a t a
r a t e of 2 , l feet-per-second (0.6 meters-per-second),
- more -
Retromaneuver
Seven and a h a l f m i n u t e s a f t e r s p a c e c r a f t s e p a r a t i o n ,
t h e Centaur s t a g e a t t i t u d e c o n t r o l t h r u s t e r s a r e used t o
r e o r i e n t t h e v e h i c l e . The r e m a i n i n g l i q u i d and gaseous
propellants a r e then vented.
The r e t r o m a n e u v e r i n s u r e s t h a t t h e r e i s no p o s s i b i l i t y
o f c r a s h i n g i n t o t h e p l a n e t and t h e r e b y v i o l a t i n g t h e M a r t i a n
q u a r a n t i n e r e s t r a i n t . The s p e n t C e n t a u r s t a g e w i l l go i n t o a
s o l a r o r b i t . I t w i l l p a s s Mars a t a d i s t a n c e o f a p p r o x i m a t e l y
a m i l l i o n m i l e s (1,600,000 k i l o m e t e r s ) .
LAUNCH OPERATIONS
The key members of the launch team move from one vehicle
to the other as required, and a small crew stays with the
vehicle not undergoing major testing in order to monitor
systems and maintain quality surveillance.
In providing launch operations, KSC handles scheduling
of test milestones and review of data to assure that the
launch vehicle has met all of its test requirements and is
ready for launch.
Because of the relatively short launch opportunity, a
special effort was made by the ULO team to develop a work
schedule that permits sufficient time to check out both
vehicles. Atlas-Centaur No. 23 was erected on Pad 3 6 In~
December 1970 and vehicle No. 24 was placed on Pad 3hA i l l
- more -
F o l l o w i n g t h i s , t h e J o i n t F l i g h t A c c e p t a n c e Composite
T e s t (J-FACT) was c o n d u c t e d a b o u t s i x weeks b e f o r e l a u n c h
t o a s s u r e t h a t t h e v e h i c l e was e l e c t r i c a l l y r e a d y f o r f i n a l
l a u n c h p r e p a r a t i o n s and t h a t t h e p r o p e r c o n n e c t i o n s were
made w i t h t h e s p a c e c r a f t . The J-FACT i n c l u d e d r u n n i n g t h e
c o m p u t e r and programmer t h r o u g h p o s t f l i g h t e v e n t s a n d
monitoring t h e d a t a t o a s s u r e c o r r e c t response t o a41
signals with the umbilical ejected.
A f t e r AC-24 was e r e c t e d and t h e b a s i c s y s t e m s were
c h e c k e d o u t , t h e p r o t o t y p e model was t r a n s f e r r e d o v e r from
AC-23. The TCD o n t h i s v e h i c l e was c o n d u c t e d a b o u t s i x
weeks p r i o r t o i t s l a u n c h , f o l l o w e d by t h e J-FACT a week
later.
I n l a t e A p r i l , t h e M a r i n e r H s p a c e c r a f t was mated on
AC-24 and a n e l e c t r i c a l a n d m e c h a n i c a l t e s t was c o n d u c t e d
p r i o r t o r u n n i n g a s e c o n d J-FACT. M a r i n e r I was e n c a p s u l a t e d
b u t w i l l n o t b e m a t e d t o AC-23 u n t i l M a r i n e r H i s s u c c e s s f u l l y
launched.
A t t h i s p o i n t , i t would h a v e b e e n p o s s i b l e t o l a u n c h e i t h e r
s p a c e v e h i c l e on e i t h e r o f t h e two m i s s i o n s . However, AC-24
was s e l e c t e d f o r t h e f i r s t m i s s i o n and a n e l e c t r i c a l - m e c h a n i c a l
t e s t a n d a s e c o n d J-FACT i s s c h e d u l e d i n e a r l y May f o r A.C-23 a s
an added a s s u r a n c e f o r a s u c c e s s f u l f l i g h t .
The Countdown R e a d i n e s s T e s t i s s c h e d u l e d f o r b o t h s p a c e
v e h i c l e s a b o u t f o u r d a y s b e f o r e l a u n c h . It v e r i f i e s t h e a b i l i t y
o f t h e l a u n c h v e h i c l e t o go t h r o u g h p o s t - l i f t o f f e v e n t s and
r e v a l i d a t e s t h e u m b i l i c a l s y s t e m . The r a n g e s , u p p o r t e l e r n e n t s
p a r t i c i p a t e a l o n g w i t h t h e s p a c e c r a f t and l a u n c h v e h i c l e j u s t
as d u r i n g a l a u n c h .
The F-1 Day F u n c t i o n a l T e s t i n v o l v e s f i n a l p r e p a r a t i o n s
i n g e t t i n g t h e e n t i r e space v e h i c l e ready f o r launch, preparing
g r o u n d s u p p o r t e q u i p m e n t , c o m p l e t i n g r e a d i n e s s p r o c e d u r e s and
i n s t a l l i n g o r d n a n c e on t h e l a u n c h v e h i c l e .
The f i n a l countdown i s p i c k e d up a t T-450 m i n u t e s , A l l
systems a r e checked a g a i n s t r e a d i n e s s p r o c e d u r e s , e s t a b l i s h i n g
t h e i n t e g r i t y o f t h e v e h i c l e and g r o u n d s u p p o r t equipment
i n t e r f a c e p r i o r t o t o w e r r e m o v a l a t T-120 m i n u t e s . L o a d i n g
o f c r y o g e n i c p r o p e l l a n t s ( l i q u i d oxygen and l i q u i d h y d r o g e n )
b e g i n s a t T-80 m i n u t e s , c u l m i n a t i n g i n c o m p l e t e v e h i c l e
r e a d i n e s s a t T-5 m i n u t e s . The t e r m i n a l c o u n t b e g i n s moni-
t o r i n g a l l s y s t e m s and t o p p i n g o f f a n d v e n t i n g p r o p e l l a n t
and p u r g e s y s t e m s . A t T-10 s e c o n d s , t h e a u t o m a t i c r e l e a s e
s e q u e n c e i s i n i t i a t e d and t h e s p a c e v e h i c l e i s c l e a r f o r
liftoff.
- more -
TRACKING AND DATA SYSTEM AND MTSSION OPRRATTCPrS
---
T r a c k i n g and o b t a i n i n g d a t a f r o m M a r i n e r s a r e p a r c cl ~ n e
mission assigned t o JPL. These t a s k s c o v e r a l l p h a se s o f t l ?
f l i g h t , i n c l u d i n g t e l e m e t r y f r o m l a u n c h v e h i c l e and s o a e e c ~ - ? r,1
t r a c k i n g d a t a on b o t h l a u n c h v e h i c l e and t h e M a r i n e r s , e o r l r a i L d
s i g n a l s and t h e d e l i v e r y o f d a t a t o SFOF.
,. -
I n t h e l a u n c h p h a s e o f t h e m i s s i o n , t r a c k i n g will b e capr'r.23
o u t by DSN w i t h a i d o f o t h e r f a c i l i t i e s . T h e s e a r e :rada:r.s or"
A i r F o r c e E a s t e r n T e s t Range and downrange e l e m e n t s o f K A S A 7 s
Manned S p a c e F l i g h t Network (MSFN) t o g e t h e r w i t h t h e . t i ? a c k i n : ~ 0
The m i s s i o n i s c o m p l i c a t e d by t h e f a c t t h a t M a r s ) - p o ; ~ r l ? 2 r
6 0 m i l l i o n m i l e s f r o m E a r t h a t t i m e of f i r s t encoun-LC?-,v i - i l
move beyond 1 0 0 m i l l i o n m i l e s t h r o u g h t h e c o u r s e o f ~ h leo r g
m i s s i o n . Meanwhile, b o t h p l a n e t s c o n t i n u e moving i n ~ h e l -
s e p a r a t e o r b i t s and t u r n i n g on t h e i r a x e s .
The DSN consists of nine specialized tracking facilities
located at four points around the Earth. Largest of these, at
Goldstone, CA, has two 85-foot (26-meter) antennas and one
measuring 210 feet (64-meters) in diameter. Other 85's are at
Madrid (Robledo dechavela and Cebreros), Spain; Johannesburg,
South Africa; and Woomera and Canberra (Tidbinbilla) Australia,
In addition a four-foot (1.2-meter) antenna at Cape Kennedy
covers pre-launch and launch phases of the flight.
For all of NASA's unmanned missions in deep space, such as
planetary and Sun-orbiting spacecraft, the network provides the
tracking information on course and direction of the flight, velocity
and range from Earth. It also receives engineering and science
telemetry, including planetary television coverage, and sends
commands for spacecraft operations. All communication lrnks are
in the S-band.
The 210-foot (64-meter) antenna at Goldstone, capable of
receiving eight times the volume of data of the other antennas,
will play a special role in Mariner '71. The 210 will. transfer,
on a daily basis, Mars TV pictures obtained and stored in each
orbit of the planet.
DSN will support the three months of basic orbital operations
by acquiring data telemetered from the spacecraft at 16,200 bits
per second through the 210-foot (64-meter) antenna. (Rates with
the 85's are 2,025 bits per second.) Data will be routed immediately
to SFOF, distributed to computers and other specialized processing
machinery, to make it ready for the experimenters.
At the same time spacecraft range and range-rate information
will be relayed from both Mariners to SFOF.
A new 50,000 bps digital wideband communications line will
-
carry data from Goldstone to SFOF. High-speed data links from
all stations are capable of 4,800 bps. These new data links allcw
real-time transmission of almost all data from both spacecraft to
JPL-SFOF.
The planning and analysis functions of Mariner '71 are
carried out by special teams of engineers, including a DSN Mission
Operations Team and a DSN Project Engineering Team. The Opera-
tions team is responsible not only for the operation of the
Network but coordination of near-Earth phase assistance and
NASCOM support. The other team has charge of resources, opera-
tions planning and configuration control.
All of NASA's networks are under the direction of the
Office of Tracking and Data Acquisition. JPL manages the DXN,
while the MSFN facilities and NASCOM are managed by NASA's
Goddard Space Flight Center, Greenbelt, MD.
The Goldstone DSN stations are operated and maintained. by
JPL with the assistance of the ~hilco-Ford Gorp.
The Woomera and Tidbinbilla stations are operated by the
Australian Department of Supply.
The Johannesburg station is operated by the South African
government through the National Institute for Telecommunications
Research.
The two stations near Madrid are operated by the Spanish
government's Instituto Nacional de Tecnica Aerospacial (INTA),
Mission Operations
O f f i c e o f S p a c e S c i e n c e and A p p l i c a t i o n s
D r . J o h n E . Naugle A s s o c i a t e A d m i n i s t r a t o r f o r OSSA
R o b e r t S . Kraemer D i r e c t o r , P l a n e t a r y Programs
H a r o l d F. H i p s h e r M a r i n e r ' 7 1 Program S c i e n t , i s t
F. R o b e r t Schmidt Manager, A t l a s - C e n t a u r
O f f i c e o f T r a c k i n g a n d Data A c a u i s i t i o n
Arnold C . B el ch er Network O p e r a t i o n s
J e t P r o p u l s i o n Laboratory, Pasadena, CA
Adm. J o h n E . C l a r k Deputy L a b o r a t o r y D i r e c t o r
Dan S c h n e i d e r m a n P r o j e c t Manager
- more -
Edwin Pounder A s s i s t a n t P r o j e c t Manager
(Near P l a n e t )
B r a d f o r d Houser P r o j e c t C o n t r o l and A d m i n i s t r a t i o n
Manager
A 1 Conrad S p a c e c r a f t Systems E n g i n e e r
Lewis R e s e a r c h C e n t e r . C l e v e l a n d
Bruce T . L u n d i n Center D i r e c t o r
Edmund R . J o n a s h C h i e f , Launch V e h i c l e s D i v i s i o n
Kennedy S p a c e C e n t e r , F l o r i d a
- more -
M A R I N E R MARS 1 9 7 1 SUBCONTRACTORS
F o l l o w i n g i s a l i s t of some k e y s u b c o n t r a c t o r s rslio
p r o v i d e d i n s t r u m e n t s , hardware and s e r v i c e s f o r t h e r ' i a r l ~ e r
Mars 1 9 7 1 P r o j e c t :
S p a c e c r a f t E n g i n e e r i n g Subsystem C o n t r a c t s
RCA S c i e n c e S u p p o r t Equipment
Van Nuys, CA
P h i l c o - WDL A n t e n n a Asserriblji
Palo Alto, CA
Motorola Eadio
Phoenix, AZ
Texas I n s t r u m e n t s T e l e m e t r y and I n f r a r e d
D a l l a s , TX Interferometer Spectrometer
General E l e c t r i c A t t i t u d e C o r t r o l and
V a l l e y F o r g e , PA Scan C o n t r o l E i e c ~ r c c i c s