sert 2 press kit

8/8/2019 SERT 2 Press Kit

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (202)9661-4155WASHINGTON,D .C . 2 0 w TEU: (202) 963-6925

: SUNDAY

January 25, 1 9 7 0

RELEASE NO: 70-8

te'!

LAUNCHING OF SERT 2

A s p a c e c r a f t t o t e s t how one type o f e l e c t r i c r oc ke t

eng ine ope r a t e s i n space i s t o b e l aunched in to E a r t h o r b i t

no e a r l i e r th an Jan. 2 9 , 1 9 7 0 .

The t e s t ' t h r u s t e r s are two electron-bombardment i o n

engi nes . Ion engines , one of se ve ra l types o f e l e c t r i c

t h r u s t e r s , may b e used i n t h e f u t u r e t o p o s i t i o n Ear th -

o r b i t i n g s p a c e c r a f t o r t o p r op e l s p a c e cr a ft t o d i s t a n t

p l a n e t s e

The National Aeronautics and Space Administrat ion

s p a c e c r a f t , SERT 2 (Space E le c t r i c Rocket Tes t ) w i l l be

launched from the Western Test Range i n C a l i f o r n i a by a

Thorad-Agena-D booster .

IPAOEB)

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SERT 2 w i l l b e placed i n a c i r c u l a r o r b i t 6 2 1 s t a t u t e

miles above the Ear uh and in a p l a n e i n c l i n e d 99.1 degrees

to t h e Equator. In t h i s o r b i t ,i t w i l l

take about lo5

minutes to complete each revolut ion.

SERT 2 w i l l provide t h e f i r s t o r b i t a l t e s t o f e l e c t r o n -

bombardment io n engines . Sa t i sf ac to ry ope rat ion f o r a

pe r io d o f s i x months or l onge r w i l l be a miles tone i n t h e

advancement o f e l e c t r i c p ropuls ion . A SERT 1 s u b o r b i t a l

f l i g h t i n J ul y 1964 provided th e f i r s t s u cc es s fu l t e s t of

an io n eng ine i n space .

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The electron-bombardment io n en gi ne was inven ted a t t h e

NASA L e w i s Research Center, Cleveland, Ohio.

Ion engines produce t i ny amounts of t h r u s t but are

p o t e n t i a l l y more e f f i c i e n t i n sp ac e th a n e i t h e r chemical

o r n u c l e a r r o c k e t e n gi n es . The SERT 2 engines genera te

t h r u s t by i o n i z i n g a v ap or iz ed p r o p e l l a n t , m ercury, e l e c t r i c a l l y

a c c e l e r a t i n g t h e i o n s , n e u t r a l i z i n g these i ons and expe l l ing

them a t extpemely h i g h speeds--on t h e o r d e r of 50,000 miles

p e r hour .

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Because t h e mass of the p ro pe l l an t ( i on s ) hc%ng expe l l ed

from t h e engine i s very small , t h e r e s u l t i n g t h r u s t is very

low, abouts i x

one-thousandth ( 0 . 0 0 6 ) o fa

pound. This g e n t l e

t h r u s t c a n be more than ample f o r rc?Pinfn% h e o r b b t s o f E a r t h

s a t e l l i t e s and, when ope rat ed continiious3.y for Tone; per iods ,

t o prope l spacec ra f t on d i s t a n t mis s ions .

Ion engines , un l ik e chemica l iwcke ts , cannot opera te i n

the atmosphere. They re qu ir e t he vacuum of space and th e re f or e

can be considered f o r use only or! s p ” w c Y a f t , s a t e l l i t e s End as

upper launch veh ic le s tages .

On t h e SERT 2 mission one ion eng ine will be operated

cont inuously f o r about s i x months t o determine t h e e n g i n e ’ s

o p e r a t i n g c h a r a c t e r i s t i c s and r e l i a b i l i t y i n the space env iron -

ment, t o confirm ground t e s t f i n d i n g s i n vacuum chambers and

t o develop and check out ion eng ine op era t io na l p rocedures .

The launch date has been se lec ted t o p lace the SERT 2

i n c on ti nu ou s s u n l i g h t f o r a t l e a s t s i x months immediate ly

a f t e r launc h. Then, f o r a pe r iod o f one t o three months, i t

w i l l be i n t h e Ear8th’s shadow f o r a port3,nn o f path o r 9 j - t .

During t h a t t i m e t h e ion eng ines w i l l no t b e o p e m t e d . After-

wards, t h e s p a c e c r a f t w i l l ag ai n be i n con tin uau s siinl._l.ght f o r

up t o e ig ht months and ope rat ion o f t h e second ion engine i s

planned a t t h a t t i m e .

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Limi t ing t h e d u r a t i o n o f ope ra t ion i s t h e amount or"

mercury propellant--29 pounds f o r each eng ine , or er,ough

t o ope ra te each eng ine fo r a maximum of nine months,

O th e r experiments on SERT 2 a r e t o determine i f long-

d u r a t i o n o p e r a t i o n o f t h e i o n engine-s pr es en ts any problems

i n (1) adio communications between t h e s p a c e c r a f t and E a r t h ,

( 2 ) t h e e l e c t r i c a l c or np at ab il it y of t h e t h r u s t e r s y s t e m and

t h e r e s t of the spacec ra f t and ( 3 ) whether exhaus t p roduc ts

I

w i l l c au se d eg r a da t io n o f s o l a r c e l l s o r t he the rma l con t ro l

and o p t i c a l p r o p e r t i e s a f v a ri o us s u r f a c e s .

A v a r i e t y o f o t h e r measurements w i l l b e made throughout

t h e SERT 2 ' s a c t i v e l i f e t i m e i n c l u d i n g data o n t h r u s t e r

e f f i c i e n c y v a r i a t i o n s : i n t e r a c t i o n s , or coupl ing, i f any,

between t h e i o n beam and the sur rounding plasma o f space;

th ru s t magni tudes; and t empera ture f lu c t ua t i on s o f an

o p t i c a l l y r e f l e c t i v e c oa t in g .

The solar arrays on SERT 2 are t h e l a r g e s t ev e r f lown

on a NASA s a t e l l i t e . The two a r r a ys , a t t a c hed nea r t h e nozz le

of th e Agena s t ag e t o prov ide e l e c t r i c power, measure f iv e b y 19

f ee t and con ta in a t o t a l o f 33 , 300 solar c e l l s .

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The reason f o r t h e b i g so la r pane l sys tem i s the i o n

engines req u i re l a r ge amounts of power f o r t h e i r opera t io n .

The approximately 1 , 0 0 0 watts needed f o r SERT 2 i s div ided

i n t o a l t e r n a t i n g a nd d i r e c t c u r r e n t ra n gi n g from 4 v o l t s

AC t o 3,000 v o l t s DC.

The SERT program i s managed by NASA's Off ice of Advanced

Research and Technology. The L e w i s Research Center i s

ass ig ned p ro je ct management f o r both t h e spa cec ra f t and the

launch veh ic le .

Launch operations are t h e r e s p o n s i b i l i t y o f NASA

Unmanned Launch Opecations, Kennedy Space Center, Fla., w i t h

suppor t p rov ided by t h e A i r Force Test Wing, Western T e s t

Range, C a l i f , , and t h e A i r Force S a t e l l i t e T e s t Center ,

Sunnyvale, C a l i f .

The NASA Goddard Space F l i g h t Center , Greenbe l t , Md.,

is r e s p o n s i b l e f o r SERT 2 o r b i t a l t r a c k i n g and data a c q u i s i t i o n

u si ng s t a t i o n s o f t h e S a t e l l i t e T ra ck in g and Data Acqu i s i t ion

Network and the NASA Manned Space F l i g h t Network.

The Thorad booster i s b u i l t b y McDQnnell-Douglas Cory.,

and t h e Agena stage i s b u i l t by Lockheed Missiles and Space

Co., Sunnyvale, Ca l i f .

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Th rust -augmentamotor separation

Pitch-down maneuver

stabil ization

\

Agena separation for gravity g radient

Tho r-powered

fl ight

separation

Representation of SERT 2 Fl i gh t Sequenaca

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thrustersA

I - -~p~ecraft R h

unit (SSU)

,--Standard Agena

clamshell shroud

,--Spacecraft support

,--Agena

,Agena booster adapter_/--

-He

_,,-Thorad extensfon_/--

c

,--Thorad/*-_-

_,--TX354-5 thrustaugmentation motors



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sert 2 press kit

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