ats-d launch presskit

8/8/2019 ATS-D Launch Presskit

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NA TIO NA L AERONAUTICS AN D SPACE ADM INISTRA TION W O 2-4155E W S WASHINGTON,D.C. 20546 TELS* W O 3-6925FOR RELEASE: SUNDAY

RELEASE NO: 68-127(THRU)

ATS-D LAUNCH SCHEDULED I

The National Aeronautics and Space Administration hasscheduled an experimental sa t e l l i t e , t h e ATS-D (ATS-N i no rb i t ) , f o r la un ch Ju l y 24 from Cape Kennedy,

The 864-lb, spacecraft w i l l be launched into a.synchronous orbit about 22,300 s t a t u t e miles above theEquator a t LO7 degrees West Longitude over t h e Pacific Oaean.T h i s w i l l place i t about 400 miles west of Quito, Ecuador.

A g ra v i t y g ra di e nt s t a b i l i z a t i o n system w i l l be t h eprime experiment of ATS-D. This system makes use of thec h a r a c t e r i s t i c s of t h e Ear th ' s g r av i t y t o s t a b i l i z e a space-c r a f t i n o r b i t .

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The spacec ra f t a l so carries a day-night camera experi-ment. Because t h e s a t e l l i t e w i l l appear t o hover over asi ng le point, and because i t s a t t i t u d e i s f i x e d r e l a t i v et o t h e Earth, t h e camera w i l l be able t o view cont i nual lythe same area of the Ear th , The camera optics are steerablefrom th e ground, t h u s permitt ing continuous observation ofstorm centers and other meteorological features of t h e E a r t h ' satmosphere.

The ATS-D, t o be launched by an Atlas-Centaur ro ck et,a l s o carries a communications experiment and an ion engineexperiment. Both of these experiments a re designed for u s eaboard a grav i t y g rad ient s a t e l l i t e .

The launch window opens a t 6:24 porn,, EIYP, Wednesday,J u l y 24, and closes a t 7 : 3 5 pome, EIYP, The window sh i f t sapproximately one minute every other day i f a decis ion ismade t o launch a t c2 l a t e r date.

The objec t ive of t h e prime mission on ATS-D i s t oexperiment w i t h ant! determine th e performance of a pass ivegr av it y gra dien t c on tr ol system which u s e s the E a r t h ' sg ra v i t y as an anchor fo r s t ab i l i z ing t h e sp ac e cra f t i n o r i b t .It i s expected t o be a lo ng- lif e, economical technique .

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The concept of the grav i ty g rad ient dates back t o S i rIsaao Newton i n the 16th Century,fo rc e s deep i n t o space, r e su l t i n g i n t h e grav i ty g rad ientThe Ear th ' s gravi'ky exertse f f e c t . This force can cause an appropriately designeds a t e l l i t e to present i t s same s i d e continuously toward theeEar th.

The Moon i s an example of g ra vi ty gradi ent s ta bi l i za t i on ,One sade cont inual ly faces Earth. The Moon's shape l i m i t st h e maximum st a b i li z a t i o n e f f e c t b u t i t i s . i r regular enoughi n shape t o r e a c t t o f o r c es e xe rt ed by the Earth over mi l l ion sof years, so i t i s s t a b i l i z e d w i t h the same side always i nview of Earth,

Engineers believe g r a v i t y gradien t -s tab i l ized satel -l i t e s w i l l have a longer space l i fet ime than those withoutt h i s feature. They are a lso less expensive than active,t h re e -a x i s s t a b i l i z a t i o n systems,

The 25l -fo ot t h i n booms used on ATS-D w i l l tend t o bendaway from the Sun as t h e r e s u l t of so la r hea ting. E a r t hc o n t r o l s t a t i o n s w i l l be able t o observe the extent of t h i sbending effect by t h e s a t e l l i t e g s te levision camera,on-board meteorological camera may a l s o be used t o s ee a boomThei n i t s field of view which i s pointing toward t he Ea r th ,

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-4-Phys ic i s t s of NASA ' s Goddard Space F l i g h t Center, Creen-

b e l t , Md., bel ieve th e booms w i l l bend about 12 fee t , con-t r i b u t i n g t o a n a n ti c i pa t e d small spacecraft po in t ing e r ror .By observ ing the axtent of boom bending, t h e y hope t o pre-d i c t and compensate f o r the poin t ing e r ror .

The Image Orthicon Camera ( I O C ) , a day-night sensor,w i l l be or b i t ed f o r the f i r s t time on ATS-D. Infrared photosof the Ear th have been taken previously by weather s a t e l l i t e s ,but night p i c t u r e s i n the vi s i bl e spect rum ( t h a t par t of t h espectrum which man can see) have not been possible,

The Image Orthicon Camera i s a meteorological te levis ioncamera (885 l i n es ) s pec i f i c a l l y designed f o r a synchronousequator ia l, g rav i ty grad ien t s t a b i l i ze d spacecraf t.

Each picture made by th e camera w i l l cover only a smallThe area of E a r t h covereda r t of the Ear th ' s v i s i b l e d i s k .

by each individual p ic ture of t h e equator ia l area w i l l be1,150 s t a tu t e m i l e s on a s ide . As a consequence, the cameraopt ics have been made so they can be direc ted t o any po in t ont h e Earth d i s k . Ground resolution w i l l be about two milesa t pic tur e ce nter when the op t ic s are aimed near the poin tdi rect ly below t h e s a t e l l i t e .

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-5-The area covered w i l l i nc re as e i n s i z e for more northerly

or souther ly areas of the Earth. Sixty-four pi ct ur es andth ree hours would be requi red t o photograph t h e e n t i r e E a r t h ' sd i s k

Night c a p a b i l i t i e s of t h i s camera system will beevaluated under various degrees of moonlight, ranging froma q u a rt e r t o a f u l l Moon.

ATS-D1 microwave communications experiment (Super HighFrequency) present on a l l ATS s pacec r af t t o date, has beendesigned for t ransmission of voice , t e l ev i s io n (co lor andblack-and-white), tel eg rap h and d i g i t a l data t o seve ral grounds t a t i o n s.

United States s t a t i o n s for t h e microwave communicationst e s t s are Rosrnan, N.C.; and Mojave, Cal i f .

Results from previous microwave communications experimentshave shown t h a t sev era l hundred s t at io n s could s imultaneouslyt ransmit and receive voice, te l ev is i on , t e l eg raph and d i g i t a ldata .

The f ou r th ATS-D experiment i s an ion engine being t e s tedaboard a s a t e l l i t e for th e f i r s t t i m e . T h i s t e s t should deter-mine how w e l l a small Ion engine, w i t h a var iable-control ledt h r u s t of only 5 t o 20 micropounds, (a mil l ion th of a pound)

keep ATS pr ec i s e ly on s t a t i on a t 107 degrees West longitude,-more-


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-6-ATS-D i s the fo ur th of seven of a series of s a t e l l i t e s

i n the NASA ATS program.B* The ATS program i s d i rec ted by NASA ' s Office of Space

Sc ien ce and App lic atio ns. Pr oj ec t Management i s under thed i r e c t i o n of NASA's Goddard Space F l i g h t Center.

NASA ' s L ew i s Research Center, Cleveland, i s responsiblef o r th e Atlas-Centaur l a u n c h veh icle . Launch ope rat ion s ared i rec ted by N A S A ' s Unmanned Launch Operations, Kennedy SpaceCenter, Fla .

Hughes Aircraft Co., Culver C i ty , C a l i f . , is responsiblef o r t h e space craf t and int eg ra t i on of space craf t experimentsf o r ATS-A through E. General Electric Go., Missile and SpaceDivisi on, Val ley Forge, Pa., i s re spons ib le f o r th e g r a v i t ygrad ien t a t t i t ud e and con t ro l system, f o r ATS-A, D and E.

General Dynamics-Astronautics, San Diego, Cal i f . , i s t h eprime con tra cto r f o r Atlas-Centaur launch vehicle .

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ats-d launch presskit

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