lunar escape systems part 2

8/6/2019 Lunar Escape Systems Part 2

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N A S A C O N T R AR E P O R T

C T O R"-

LO IN COPY: RETURN T OAFWL (WLOL )

KIRT'LAND AFB, N MEX

L U N A R E S C A P ESYSTEMS (LESS)FEASIBILITY STUDYVolume I - Summary Reportby J . 0.MutxenuuerPrepared byN O R T H A M E R I C A NR O C K W E L L C O R P O R A T I O NDowney, Calif.for Laagley Research CenterN A T I O N A LE R O N A U T I C SN DP A C ED M I N I S T R A T I O N W A S H I N G T O N , D. C. J U N E 1970


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TECH LIBRARY W F B , NY-NASA CR-1619

LUNAR ESCAPE SYSTEMS (LESS)FEASIBILITY STUDY

Volume I - Summary ReportBy J. 0 . Matzenauer

Issued by Originator as Report No. SD 69-598-1

Prepared under Contract No. NAS 1-8923 bySPACE DIVISION, NORTH AMERICAN ROCKWELL CORPORATIONDowney, Calif.for Langley Research CenterNA TIONA L AERONAUTICS AND SPACE ADMINISTRATION

For sale b y the Clearinghouse for Federal Scientif ic and Technical nformationSpringfield,Virginia 22151 - CFSTI price $3.00


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FOREWORD

T h i s s u m m a r y r e p o r t w a s p r e p a r e d b y t he S pa c eDiv ision of Nor th Am er ican Rock wel l Corpora t io nunder Cont rac t NAS1-8923 fo r NASA -Langley Researc hC e n t e r ( L R C ) . A d e t a i l ed ech n i ca lv o lu m e ,C o n t r ac -t o r ' s N u m b e r SD 6 9 - 5 9 8 , w as a l s o p r ep a r ed . B o thr e p o r t s w e r e p r e p a r e d i n t h e s t y l e r e q u i r e dby NASAPubl ica t ionsManualSP-7013 ,1964 .

T h e p r im ar y s t u d y t e am co n s i s t ed of t he f ol lo w in gp e r s o n s :

J . 0. M atzen au e r - P r o g r a m M a n a g e rD.H.Hengeve ld - P r o j e c tE n g i n e e r ,P a r a m e t r i cD.A.Engelsand - P r o j e c tE n g i n e e r s ,R . E . Oglevie - P r o j e c tE n g i n e e r ,G u i d a n c eV . V . V an C am p - P r o j e c tE n g i n e e r ,D e s i g nA . D. Kazanowski - C o n s u l t an t f o r L u n a r

O p e r a t i o n a l I n f o r m a t io nG . C.cGeetabi l i tyndontrol

and Navigat ionI n t eg r a t i o nS c i en ce an d V i s ib i l i t y

D. F. Bender and - CSM Rendezvous Analys i sM. R. Helton

iii

"


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CONTENTS

P a g eINTRODUCTION .OBJECTIVES .A P P R O A C H .PRINCIPA L ASSUM PTIONS AND GROUND RULESSIGNIFICAN T RESULTS AND DATA .

Parame t r i c Opera t iona l n fo rmat ion .Guidance and Control Techniques .P a r a m e t r i cD e s i g nn f o r m a t i o n .

CONCLUSIONSADDITIONALRESEARCHRECOMMENDATIONS .

A er o n au t i c sBio techno logy ndH u m anResearch .E lec t r o n i c san dC o n t r o l .M ate r i a l s an d S t r u c tu r e sN u c l ea ry s t em s .P r o p u l s io n an d P o w er G en e r a t i o n .

V

vii

11344

101418191 919202 02020


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ILLUSTRATIONS

F i g u r e P a g e

56789

1011121 31 41 516

Studybjectivesnd 2T r a j e c t o r yr o f i l e s . 4E n e r g ye q u i r e m e n t so rw o - s t e pt e e r i n gr o f i l e . 6C o m p a r i s o n of S t e e r i n g H i s t o r i e s f o r B o o s t t o

6 0 -Nau t i ca l -Mi lerb i t . 6O r b i t a lc c u r a c i e se r s u sh r u s t - t o - W e i g h tr r o r s . 7O r b i t a lc c u r a c i e se r s u si t c hr r o r s . 7T y p i c a le o m e t r y 9Closeocking . 9Sunncidence a s a Function of Stayim e . 10C o m p ar i so n of Kin es th e t i c an d Hard wi re Han d l in g

Qu a l i t i e sp t imiza t ionapabi l i ty . 11Effec t of T h r e e - S i g m a S t e e r i n g E r r o r s o n M i n i m u m

Alt i tude . 13Kin es th e t i con t ro lonf igura t ion . 14L E S S H a r d w i r e C o n t r o l C o n f i g u r a t io n W i t h V i s u a lSight . 1 5L o w e r i n g LESS tou n a rur face . 16LESS Fl ig h tonf igura t ionL o n g - R a n g ely e rers ion of LESS 18

T A B L E S1 E f f e c t of I n d i v i d u a l r r o ro u r c e s2 Weightreakdown - T y p i c a la r d w a r eo n t ro leh ic l e . 1513

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LUNAR ESCAPE SYSTEMS (LESS)FEASIBILITY STUDY, SUMMARY RE PO RT

B y J . O . M a t z e n a u e rSpace Div is ion , Nor th Amer ican Rockwel l Corpora t ion

INTRODUCTION

T h i s r e p o r t s u m m a r i z e s t h e resu l t s of a Ph as e A feas ib i l i ty s tudy ofl u n a r e m e r g e n c y e s c a p e - t o - o r b i t s y s t e m s c o n d u c t e d b y t h e S p a c e D i v i s i o nof Nor th Ame r ican Rock wel l (NR) . Mr . A. W. Vogeley was con t rac t t ech-n i c a l m o n i t o r a t NASA-LRC.

T h e m i s s io n of t h e l u n a r em er g en cy e s cap e - to - o r b i t s y s t em (LESS)i s t o p r o v i d e a me an s fo r t he c rew of the lunar module (LM) o r ex tended LM( E L M ) t o e s c a p e f r o m t h e s u r f a c e i n t h e e v e n t t h a t t h e L M / E L M a s c e n ts t a g e i s u n s a f e o r u n ab l e t o t ak e off i n to o r b i t . T h e L E S S r o l e i s t o c a r r yth e tw o a s t r o n a u t s t o t h e CSM in o r b i t w i th in t h r ee t o f o u r h o u r s .

A d e t e r m in ed e f f o r t h a s b een m ad e t h r o u g h o u t t h e A p o l lo p r o g r am toin co r p o r a t e ev e r y r ea s o n a b l e m ean s of a s s u r in g c r ew s a f e ty an d m i s s io ns u cces s .Dev elo pme nt of theLESSveh ic le ,however ,wi l lp rov idei n c r c a s e d c r e w s a f e t y m a r g i n s by c o v e r in g p o s s ib l e f a i lu r e s of t h e c r i t i c a ls ing le -eng ined LM/ELM ascen t s tage .

Both NASA and NR ha ve ca rr i ed on extens ive s tudy act iv i t ie s on m is -s i o n s an d s y s t em s b ey o n d ea r l y A p o l lo . T h es e e f f o r t s h av e s h o w n th a t c r ewsafe ty a rge ly paces he ach iev emen t of g rea te r exp lo ra t ion . Thus , anys y s t e m o r p r o c e d u r e t h a t p r o m i s e s t o i n c r ea s e m i s s io n s a f e ty h a s p o t en t i a lf o r p e r m i t t i n g a f a s t e r r a t e of ach iev ing exp lo ra t ion goa ls .

B e f o r e t h i s s t u d y , a p r e l i m i n a r y f e a s i b i l i ty a n a l y s i s c o n d u c t e d a tNASA-LRC ha d indi cat ed that a s imple f ly ing p la t fo rm concep t migh t be ade-q u a t e t o c a r r y t h e c r e w t o a sa fe o rb i t . The in ten t ion was to ob ta in neces -s a r y s a f e ty an d r e l i ab i l i t y t h r o u g h u s e of s im p le s y s t em co n cep t s r a th e rthan h rough he more usua l r edundancy approach . L ikewise , unsoph is t i -c a t ed g u id an ce an d co n t r o l t e ch n iq u es w e r e d e s i r ed f o r u s e w i th s im p leascen t p ro f i l es . In add i t ion , po ten t ia l ava i lab i l i ty of a ll t h e LM as c en t s t ag ep r o p e l l an t s (5000 pounds ) ind ica ted tha t l i t t l e emphas i s need be p laced onmin imiz ing p rope l lan t r equ i rements , a l though a low v eh i c l e d r y w e ig h t i sn e c e s s a r y .

S t u d y d e t a i l s a n d p a r a m e t r i c d a t a , w h i c h a r e s u m m a r i z e d i n t h i s d o c u -m en t , c an b e f o u n d in t h e m a in t e ch n i ca l r ep o r t v o lu m e SD 69-598. Also int h e m a i n r e p o r t a r e m o r e d e t a i l ed co n c lu s io n s an d r eco m m en d a t i o n s f o rf u r t h e r e f f o r t .

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OBJECTIVES

The s tudy ob jec t iv es were to de te rmin e the feas ib i l i ty of s imp lee s cap e s y s t em co n cep t s , t o p r o v id e a spe c t r um of ope ra t iona l da ta on the seconcep ts , and to iden t i fy t echn iques f eas ib le and su i tab le fo r ca r ry ing ou tt h e e m e r g e n c y e s c a p e m i s s i o n . T h i s n f o r m a t i o n , o g e t h e r w i t h c o n c e p t u a ld e s i g n s , s u r f a c e p r e p a r a t i o n r e q u i r e m e n t s , a n d l o n g - r a n g e s u r f a c e - t o -s u r f ace f l i e r ap p l i c a t i o n d a t a , w as t o p r o v id e s u p p o r t i n g m a te r i a l f o r s y s -t em d ev e lo p m en t d ec i si o n s b y NASA an d f o r t h e s im u la t i o n t e s t p r o g r am atNASA-LRC.

APPROACH

T h e o v e r a l l o b j e c t i v e s a n d t h e a p p r o a c h t a k e n i n t h e s t u d y a r e s u m -m a r i z e d i n f i g u r e 1. Major inpu ts cons i s ted of the mos t per t inen t da taf r o m a s s o c i a t e d s t u d i e s s u c h a s N A S A - L R C i n i t i a l s y s t e m s t u d i e s , t h er e c e n t P h a s e B Lunar Flying Vehicle (LFV) Study for NASA-MS C, the largebackground of Apol lo sys tems data , and the NASA -LRC f lying lunar excur-s i o n e x p e r i m e n t a l p l a t f o r m ( F L E E P ) p r o p o s a l e f f o r t .

In t h e p a r a m e t r i c d a t a a n d s y s t e m a n a l y s i s e f f o r t , p e r f o rm a n c e i nte rm s of boo s t t r a je c to r ies , CSM rendezvous and dock ing, and the sub jec tof v i s i b i l i t y co n d i t i o n s w e r e t r e a t ed p a r am e t r i c a l l y t o p r o v id e a backgroundof opera t ion a l in fo rmat ion wi th in which sys tem and des ign i t e ra t ions cou ldbe made . Guidance and s tab i l i ty concep ts and techn iques were a l so exam-ined a s b r o a d l y a s p o s s i b l e a s a b a s i s f o r s u b s e q u e n t s y s t e m s s y n t h e s i sand in tegrat ion.

In t h e s y s t em s i n t eg r a t i o n an d co n cep t d ev e lo p m en t a c t i v i t y , t h e g u id -an ce an d co n t r o l t e ch n iq u es t h a t w e r e p r ev io u s ly t r e a t ed a s b a s i c v a r i a b l e sw er e i n t eg r a t ed i n to p r ac t i c a l d e s ig n co n f ig u r a t i o n s. R ea l i s t i c ev a lu a t i o nof weight and balan ce was used in the guidance and control analy ses and theo v e r a l l f e a s ib i l i t y d e t e r m in a t i o n . A l s o a t t h i s s t ag e i n co n cep t s y n th e s i s ,i t e r a t i o n s w e r e m ad e b ack t h r o u g h t h e p e r f o r m an ce l o o p . T h e r e s u l t swere feas ib le gu idance and co n t ro l combina t ions and concep tua l conf igura-t i o n s t h a t r e f l e c t t h e f ea tu r e s , co n s t r a in t s , an d r e s u l t i n g ch a r ac t e r i s t i c sf o r s e v e r a l c l a s s e s of v e h i c l e s . T h e c la s s e s a r e e s t a b l i s h e d b y th e b a s i ccon t ro l mode and modi f ied by the p ropu ls ion cho ices .

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O B J E C T I V E .DETERMINEECHNICALLY FEASIBLE ESCAPE SYSTEM CONCEPTS.PROVIDE PARAMETRIC,OPERATIONAL & DESIGN NFORMATION-1"

LRCSTUDIESPARAMETRICOPERATIONAL

APOLLO DATA VISIBILITY

NASA STUDIES DOCKING Gh C SYSTEMSYNTHESISCONFIGURATIONS

PARAMETRICADV SYS/MISSION SYSTEMSDESIGN DATASTUDIES WEIGHT a

BALANCELFV

0 FLEEP APPLICATIONI

ANALYSIs CONCEPT APPLICATIONSDEVELOPMENTF i g u r e 1. - Stu d y Ob jec t iv es an d Ap p ro ach

F o r t h e s u r f a c e o p e r a t i o n s a n d a p p l i c a t i o n s e f f o r t , t h e p r o b l e m s ofd e p l o y i n g a n d p r e p a r i n g t h e e s c a p e s y s t e m f o r u s e w e r e e x a m i n e d . T h er e s u l t s w e r e c a r r i e d t h r o u g h d e s i g n a s a p p r o p r i a t e t o a i d n e st ab li sh in go v e r a l l s y s te m f e a s i b i l it y . U t i l iz i n g h e e s t a b l i s he d P h a s e B L F V s tudyground ru les and techniqu es , the app l ica t io n of LESS t o l o n g - r a n g e f l y e r( L R F ) s u r f a c e - to - s u r f a c e m i s s i o n s w a s e x a m i n e d . R e q u i r e d c h a n g e s w e r ed e f i n e d , a n d h e re s u l t i n g p e r f o r m a n c e a s a f l y e r w a s c a l c u l a t e d . T h ee f f ec t s of th ese f ly e r mis s io n ch an g e s wer e th en ev a lu a t ed in t e rm s of e f f ec ton t h e b a s i c e s c a p e m i s s i o n .

Outpu ts of the s tudy spanned a s pe c t ru m of pa ram etr ic ope ra t ion a li n f o r m a t i o n c o v e r i n g f o u r b a s i c a s c e n t - t o - o r b i t t r a j e c t o r i e s t o v a r i o u so rb i t a l a l t i t u d es . A l so in c lu d ed were th e e f f ec t s of su ch sy s t em v a r i ab le sa s t h r u s t - t o - w e i g h t , s p e c i f i c i m p u l s e , a n d t r a j e c t o r y s e n s i t i v i t y t o m a j o rs y s t e m e r r o r s . V i s i b i l i t y e f f e c t s w e r e d e t e r m i n e d f o r b o t h t h e a s c e n t a n dren d ezv o u s p o r t io n s of th e mis s io n . En e rg y an d p h as in g r eq u i r em en t s fo rr e n d e z v o u s w e r e t r e a t e d e x t e n s i v e l y i n a p a r a m e t r i c m a n n e r f o r v a r i o u scondi t ion s and re la t ionsh ips be twe en CSM orb i t and LES S f ina l o rb i t . Thesee n e r g i e s w e r e r e l a t e d t o p r a c t i c a l m i s s i o n p l a n n i n g f a c t o r s : t i m i n g , l o c a -t io n of o rb i t n o d es an d ap ses , an d p lan e ch an g es . Eq u ip m en t cap ab i l i t i e s ofth e CSM were ev a lu a ted an d p e r fo rman ce e s t ima te d fo r th e r en d ezv o u st r a c k i n g a n d i n t e r c e p t t a s k s . F i v e t y p i c a l c o n c e p t u a l d e s i g n s f o r k i n e s -t h e t i c , h a r d w i r e , a n d s t a b i l i t y - au g m e n t e d c o n t r o l m o d e s w e r e p r e p a r e d t oi l l u s t ra t e d e s i g n f e a t u r e s a n d i n t e r f a c e s b e t w e e n s u b s y s t e m s a n d e l e m e n t s .V a r i a t i o n s i n t h e d e s i g n s w e r e p r o d u c e d f o r d i f f e r e n t o r a l t e r n a t iv e b a s i cp ro p ul s io n co n f ig u ra tio n s . Dep lo y men t of th e LES S f ro m an LM /EL M was2


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examined and the fue l ing and p repara t ion fo r l aunch descr ibed . Long- rangesur face f lyer adap ta t ions of LESS were s tud ied , and two concep tua l des ignsw er ed ev e lo p ed o rco n cep t sw i thb as i ca l l yd i f f e r en tp r o p u l s io nconf igurat ions .

A theo ry of hand l ing qua l i t i es op t imiza t ion was deve loped , and cor -re la t ion was made wi th NASA-LR C s imula t ion da ta ob ta ined fo r k ines the t icc o n t r o l . C o r r e l a t i o n b e t w e e n a l t e r n a t i v e p i l o t r a t i n g s y s t e m w a s madet o as s i s t i n m a k i n g t r a n s l a t i o n s f r o m o n e s y s t e m t o t h e o t h e r . D e s i g ncu r v es w e r e p r o d u ced t o s h o w b as i c r e l a t i o n s h ip s b e tw een d e s ig n v a r i ab l e sf o r h a r d w i r e c o n t r o l . F u n d a m e n t a l g u i d a n c e e l e m e n t s w e r e e x a m i n e d a n da ll poss ib le v i sua l and ns t rument r e fe rence sys tems den t i f i ed . The bes tconce p ts were eva lua ted , and comb ina t ions of gu idan ce and con t ro l e leme ntsw e r e i n t e g r a t e d t o s y n t h e s i z e c o m p l e t e s y s t e m s . G u i d a n c e e r r o r a n a l y s e sw e r e p e r f o r m e d t o s h o w t h e e s t i m a t e d o r b i t a l i n j e c t i o n e r r o r s e x p e c t e dw i th v a r io u s m ech an i za t i o n s . G u id an ce an d co n t r o l eq u ip m en t m ech an i za -t ion was s tud ied to de te rm ine re la t ive weigh t , vo lum e, and powe r of cand i -d a t e h a r d w a r e a s well a s t o a s s e s s t h e r e l a t i v e f e a s i b i l i t y of those concep ts .

PRINC IPAL ASSUM PTIONS AND GROUND RULES

The s tudy was conducted with a m i n i m u m of r e s t r i c t iv e g r o u n d r u l e s .The p r inc ipa l g round ru les fo l lowed were :1.2.

3 .

4.

L M / E L M p r o p e l l a n t s a r e t o b e u s e d f r o m t h e a s c e n t s t a g e .M i n i m u m e q u i p m e n t a n d s i m p l i c i t y , r a th e r t h a n r e d u n d a n c y , a r et o b e s t r e s s e d .T h e s p ace - s u i t b ack p ack i s t o b e u s ed foi- c r ew l i f e s u p p o r t an den v i r o n m en ta l co n t r o l an d f o r co m m u n ica t i o n s .M i s s i o n s t a y - t i m e s a r e t o b e u p t o 14 d ay s .

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SIGNIFICANT RESULTS AND DATA

P a r a m e t r i c a p e r a t i o n a l I n f o r m a t i o n

A s c e n t T r a j e c t o r ie s . - A s e r i e s of a s c e n t - t o - o r b i t t r a j e c t o r y p r o -f i l e s w a s e x a m i n e d . F l i g h t p a t h s h a p e i s i n d i c a t e d i n f i g u r e 2 w i t h s k e t c h e sof veh ic le a t t i tude dur ing the var ious por t ions of t h e a scen t p ro f i l e . Th ec a l c u l u s - o f - v a r i a t i o n o p t i m u m t r a j e c t o r y p r o v i d e s a c o ns t an t ly c h an g in gv eh ic l e a t t i t u d e to y i e ld th e min imu m en e rg y o r A V r eq u i r ed . (No tshown,b u t a l s o c o n s i d e r e d , w a s a l i n e a r p r o f i l e of v e h i c l e a t t i t u d e v e r s u s t i m ewh ich c lo se ly ap p ro x ima tes th e o p t imu m p ro f i l e en e rg y r eq u i r emen t . )T h e s e p r o f i l e s w o u l d b e a p p r o p r i a t e f o r a fa i r ly h igh ly mechanized gu idancean d co n t ro l sy s t em co n cep t . Th e th r ee - s t ep p ro f i l e co n s i s t s of a v e r t i c a lr i se p o r t io n fo l lo wed b y seq u en t i a l p i t ch o v e r to two o th e r v eh ic l e a t t i t u d es ,the las t one be ing near -hor izon ta l (wi th the r igh t va lue of th rus t - to -w eigh t ) .T h r e e s t e p s w e r e f o u n d t o b e s u f f i c i e n t t o p r o v i d e a f a i r l y c l o s e a p p r o x i m a -t io n to th e min imu m en e rg y r eq u i r ed ( ap p ro x ima te ly 5 p e r c e n t ) .

C 0 V (OPTIMUM) &STEP E L M 2-STEP 2-STEP

A//W@/ / /

h/

ENERGY: MINIMUM"G K

NEAR-MINEAR-MINIG HCOMPLEXITY: HIGH MED LOW LOWF i g u r e 2. - T r a j e c t o r y P r o f i l e s

Th e two - s t ep p ro f i l e o n th e r ig h t of f ig u re 2 c o n s i s t s of a v e r t i c a lascent fol lowed by a p i t ch o v e r to n ea r -h o r i zo n ta l t h ru s t a t t i t u d e . Th e p ro -f i l e h as th e ad v an ta g e of b e in g s imp le to mech a n ize in t e rm s of g u id an cean d co n t ro l , b u t in v o k es a l a r g e p e n a l t y i n t h e e n e r g y r e q u i r e d , a b o u t1 0 0 0 f p s c o m p a r e d t o o p t i m u m p r o f i l e ( a p p r o x i m a t e l y 1 5 p e r c e n t ) .4


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T h e b en t tw o - s t ep p r o f i l e co n cep t s h o w n p r o v id es t h e co m b in ed ad v an -t a g e s of low energy (equivalent to 3 s t e p ) a n d t h e s i m p l i c i t y of only one s tepchang e dur ing ascent . The vehic le takes off with only a s h o r t v e r t i c a l r i s e ,t h en p i t ch es o v e r w i th t h e thrus t axis about 30 d e g r e e s off v e r t i c a l an dbeg ins to bu i ld up tangen t ia l ve loc i ty es sen t ia l ly f rom l i f to f f . Th is p ro f i l e(with a 1 0 - s eco n d v e r t i c a l r i s e f o r o r i e n t a t i o n ) h a s b e e n , u t i l i z e d i n t h e m o s tr e c e n ts i m u l a t i o n e s t i n g a t N A S A - L R C . orwhich ra jec to ryda tawerein f o r m a l ly f u r n i s h ed .

The t r a jec to r ies were exam ined to de te rm ine the in f luen ce of manyv a r i a b l e s : i n i t i a l v e r t i c a l a s c e n t t i m e o r a l t i t u d e , i n i t i a l t h r u s t -w e i g h tr a t i o , a t t i t u d e r e f e r e n c e b a s i s ( i n e r t i a l s p a c e o r l o c a l l u n a r h o r i z o n ) ,en g in e s p ec i f i c m p u l s e ,a n d s t epch an g e im in g .T h e v a r i ab l e sw er e f o u n dt o a f f e c t t h e v a r i o u s t r a j e c t o r y p r o f i le s i n m u c h t h e s a m e w a y d e s p i t e t h eb as i c p r o f i l e d i f f e r en ces .

F i g u r e 3 shows the var ia t ion of asc en t ene rgy requ i red ( A V ) f o r tw oty p i ca l a t t i t u d e p r o f i l e s a s a f un c ti on of i n i t i a l t h r u s t - t o - w e ig h t ( T /W ) r a t i of o r v a r i o u s t a r g e t a l t i t u d e s . It i s n o t ed t h a t a T /W of about 0. 3 i s o p t i m u mf o r m in im u m b o o s t en e r g y f o r t h e h ig h e r o r b i t s of m o s t co n ce r n , 6 0 n au t i c a lm i l e s . T u r n i n g l o s s e s a s s o c i a t e d w i t h l o w e r o r b i t s c a u s e s o p t i m u m T / W t obe sh i f ted to h igher va lues . The f l igh t a t t i tudes ob ta ined in the var ious p ro -f i l e s a r e shown in f igure 4 , with the ca lcu lus -o f -var ia t ion (COV) o r opt i -m u m t r a j e c t o ry a s a b a s e . P i t c h a t t i t u d e i s m e a s u r e d i n d e g r e e s f r o mloca l hor izo n ta l . The inse t cu rve a l so shows how the numb er of t r a j ec to ryp r o f i l e s t e p s a f f e c t s t h e b a s i c b o o s t e n e r g y ( A V ) r e q u i r e d .

T r a j e c t o r y e r r o r s e n s i t i v i t y s t u d i e s of t h e p e r t u r b a ti o n s in t h e t a r g e to r b i t a l t i t u d e r e v e a l e d t h a t t h e p r i n c i p a l e r r o r s o u r c e s w e r e a s s o c i a t e d w i t hp i tch a t t i tude and T / W . T h e s e e r r o r s r e s u l t i n v a r i a t i o n s i n b u r n o u t c o n d i -t i o n s , of w h ich t h e m o s t c r i t i c a l i s p e r i l u n e a l t i t u d e . T /W e r r o r s of th emagni tude expected (*4 perce n t ) cou ld no t be to le ra te d wi th eng in e cutof fcontrolled by a s im p le t im e r . C o n t r o l b y A V , util izing output f r o m a n i n t e -g r a t i n g acce l e r o m e te r , w as f o u n d t o b e r eq u i r ed f o r b o th t h e a t t i t u d e p r o f i l es t ep s an d en g in e t h r u s t cu to f f . E r r o r s en s i t i v i t i e s a r e shown in f igure 5 f o rthe o r i g i na l t im e ba s i s of con t ro l an d a l so fo r con t ro l of f ina l cu to ff w i th andwi thou t s tep change con t ro l by AV. Some comb inat ions with high or lowT / W would resu l t in s a fe per i lune bu t a very high apolune, which wouldmake subsequen t CSM rendezvous d i f f icu l t . Cu to f f on AV m p r o v e s t h ep e r i l u n ec l e a r a n c e o r o wT / W ,b u t r u l y a t i s f a c t o r yo r b i t sa r eo n l yachieved with both s tep and cutoff by AV.

It w as f o u n d t h a t e l l i p t i c a l , r a t h e r t h an c i r c u l a r , t a r g e t o r b i t s d e s e n -s i t i z e t h e v a r i a t i o n i n p e r i l u n e a l t i t u d e w i t h p i t c h a t t i t u d e e r r o r s ( f i g . 6 ) .F o r i n s t a n c e , a r e a s o n a b l e p i t c h e r r o r of p l u s o n e d e g r e e f o r a t a r g e t e d6 0 - n m c i r c u l a r o r b i t w o u l d r e su l t in a pe r i l un e of about 20 n m ; w h e r e a s , a n

5


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"- O P T1 M U M ( RE F)O R B I TA L T I T U D E (N M I )I F TOFF T I W( L B S I L B ) 20 40 6 0 80

,6200 8600 9400B O O S TC H A R A C T E R I S T I C V E L O C I T YF P S )

F i g u r e 3 . - E n er g y R eq u i r em en t s f o r T w o - s t ep S t ee r i n g P r o f i l e .LIFTOFF T/W = 0.3 LBS/LB

" I I I,2-STEP

I I A T T IT UDET E P S EFFECT OF NUMB E R OF3-STEP AV (KFPS)

P I T C HATTITUDE(DEGREES)

WITH VERTICAL

2 4 WI h- NO. O F S T E P SB E NT2-STEP

-20 I 1 \0 20 000 600T I M E ( S E C O N D S )

F i g u r e 4. - Com par i son o f S teer ing His to r ies fo r Boos tto 60-Naut ica l -Mi le Orb i t

R I S E

6


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A P S EA L T IT UDE(NM)1 60 \\

A P OL UNE\/

\ ii\ /80 \ i , 0\ * ,040

-. -.-.- STEP & CUTOFF ON T I M ETE P ON TIME,CUTOFFON AVSTEP & CUTOFF ON AV

80 I-- PER I LUNE

-6 -4 -2 0 2 4 6L IF T OFF T I W E RROR (P E RCE NT )

F i g u r e 5. - O r b i t a l A c c u r a c i e s V e r s u s T h r u s t - t o -W e i g h t E r r o r sA P S EA L T IT UDE(NM)

200

80 /-N O M A P OL UNE

408 01p f i \ y ~ l ~ ~ C I R C U L A R )- 8 0 N M

PER1 LUNE40

0 ./


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e r r o r of 2 - 1 / 2 d e g r e e s w ou ld r e s u l t i n t h e s a m e p e r i l u n e f o r a 6 0 - by1 2 0 - n m a r g e to r b i t .T h e s eh i g h e re l l i p t i c a l o r b i t s ,h o w e v e r ,c a nc a u s esubsequ ent rendez vous and t ransear th in ject io n penal t ie s becau se of non-op t imum in jec t ion geomet ry ; consequen t ly , c i r cu la r t a rge t o rb i t s may p ro-v id e t h e b e s t o v e r a l l co m p r o m is e .

CSM rendezvous and docking. - A n ex t en s iv e co m p u te r an a ly s i s w asu n d e r t ak en f o r CSM t r an s f e r s u n d e r v a r i o u s o r b i t a l co n d i t i o n s t o e s t ab l i s hpara met r ica l ly the scope and charac te r of the maneuvers invo lved in LESSrendezvous . Contour maps of energy requ i red were deve lop ed fo r typ ica lCSM and LESS ni t ia l condi tions . The amount of en er gy re qu ir ed fo r mo stl ikely orbi ta l condi t io ns were found to be within the current CSM budgeta l lowance of 790 fps fo r LM r esc ue ma ne uv ers .

The CSM orbi t determ inat ion and guidan ce capab i l i t ies current l yab o a r d f o r b ack u p LM r e s cu e w e r e f o u n d t o b e ad eq u a t e f o r t r a c k i n g t h eLESS and com puting the rendezvous t ra jectory within one-four th orbi t f romburnou t (one-ha l f hour ) . The LESS wi l l r equ i re a VHF t ransponder andf lash ing- ligh t beacon . The CSM can then per f o rm the t r an s fe r to the LESSorb i t w i th in ano ther one-ha l f to th ree- four ths o rb i t (180- to 270-degreet r an s f e r ). T y p i ca l r en d ezv o u s g eo m e t r y s l l u s t r a ted n f i g u r e 7.

Severa l methods were s tud ied fo r dock ing the smal l LESS veh ic le wi ththe CSM. The p re f e r red con cep t i s a hard dockin g on the CSM nose with aspec ia l dock ing d rogue on the LESS, as shown in f igure 8. T h i s s c h e m ekeeps the LESS f i rmly pos i t ioned whi le the c rew t rans fe r s v ia hand ho ldsand sa fe ty t e th er s to the CSM main ha tch , r educ ing the poss ib i l i ty of da ma geto the hea tshie ld by the LESS. Another cons iderat ion i s the poss ib le con-t am in a t i o n o r d am ag e of t h e s p ace s u i t s f r o m CSM r ea c t i o n co n t r o l s y s t e m(RCS) je t impingement .

Vis ib i l i ty cons idera t ions . - Visibi l i ty w a s cons idered th roughout theLESS miss ion s tudy. Lunar condi t io ns res t r ic t the viewin g of obje ctsbecause of shadow ing f rom bl inding glare when s ight ing i s n ea r t h e s u n an df r o m s o l a r g l a r e o r r e f l e c t i o n s f r o m i n s t r u m e n t s . R e f l e c t e d g l a r e f r o m t h elu n a r s u r f ace a l s o r ed u ces s en s i t i v i t y an d co n t r a s t . T h e a s t r o n au t s ' v i s o r sm u s t m a in t a in f i l t e r i n g t o p r ec lu d e ex t r em e s of g l a r e , y e t a l l o w p e r cep t i o nof l e s s w e l l l ighted objects .

C o n s id e r in g t h e w id e s p r ead of s u r f a ce s t ay t im es t o b e co n s id e r ed ,t h e r a n g e of p o s s ib l e s u n an g l e s b eco m es im p o r t an t . LESS ab o r t co u ld b es h o r t l y a f t e r L M /E L M l an d in g at sun ang les of 1 0 d eg r ee s b eh in d o r w i thsun ang les up to 180 degrees ahead (on the hor izon) wi th 14 d a y s s t a y t i m e ,a s s een i n f i g u r e 9. D u r in g r en d ezv o u s , t h e LESS w i l l b e e s s en t i a l l y i n t h esun a t t imes , mak ing v i sua l t r ack ing d i f f icu l t , These p rob lems of viewingtend t o d i s c o u r a g e u s e of s im p le v is u a l g u id an ce s i g h ts .8


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7-DAY MISSIONELM MISSIONSUNNGLE ONDA Y NUMBER

S UN A NGL E

loo SUNNGLE TERMINATOR \ TI5

F i g u r e 9 . Sun Inc idence as a Func t ion o f S tay T imeVisibil i ty and acquistion of the targ et with the CSM optics was found

to bea p rob lem . I t i s cu r re n t ly und er s tud y a t NASA-MSC in connec t ionwith LM r e s c u e .

Guidance and Control Techniques

Stabi l i tv and control . - Substan t ia l quant i t ies of data f r o m c oNntractorand other s tudies of the lunar f lying vehicl e were applied in . this s tudy,Te thered - f l igh t -veh ic le and f ixed-base - s imula to r t es t ing had ind icated tha tthe manua l s tab i l i ty and con t ro l sys tem (SCS) modes were no t adequa tewhere spo t l and ings and smal l ve loc i t i es a t touchdown were requ i red . Thes tab i l i ty and con t ro l p rob lem fo r the LESS i s not so a r d u o u s , b e c a u s e t h e r ei s no need to con t ro l t r ans la t iona l ve loc i t i es t o a f ine degree . The con t ro lt a s k i s r e d u c e d t o m a i n t a i n i n g t h e p r o p e r v e h i c l e a t t i t u d e f o r g u i d a n c era ther than t r ans la t ion a l ve loc i ty con t ro l . Sys tem s tab i l i ty and handl ingqual i t ies , however , were found to inf luence s t rongly the gu idance accura-c ies ach ievab le .

C o n s id e r ab l e e f f o r t w as ex p en d ed i n s t u d y in g r e s u l t s of v a r io u s o th e rco n t r ac to r and NASA s im u la t i o n s . C o r r e l a t i o n s b e tw een t h eo r e t i c a l s t a -b i l ity and p i lo t work load were de te rmined . A hand l ing qua l i t i es theory tha t10


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w a s e s t a b l i s h e d p e r m i t s p r e d i c t i o n of t h e b e s t h an d l i n g q u a l i t i e s a t t a i n ab l ea s well as t h e s y s t e m c o n s t a n t s n e c e s s a r y f o r a c h i e v e m e n t of these hand l ingqua l i t i es . It is expec ted tha t subs tan t ia t ing da ta wi l l u l t imate ly be an ou tpu tof the NASA-LRC s imulat i ons .

S ev e r a l p o s s ib l e v eh i c l e co n f ig u r a t i o n s an d s t ab i l i t y an d co n t r o lmod es were ana ly zed . It was conc luded tha t k ines the t ic con t ro l may bep o s s ib l e , t h o u g h m ar g in a l , f o r t h e LESS ( p en d in g m o r e s im u la to r d a t a ) an dt h a t h a r d w i r e c o n t r o l a p p e a r s p r o m i s i n g . H a r d w i r e t h e o r e t i c a l l y p e r m i t sm o r e f r eed o m in d e s ig n l ay o u t an d ex h ib i t s s l i g h t l y b e t t e r h an d l i n g q u a l i t i e s( l e s s p i l o t w o r k lo ad ) .

F ig ure 10 shows theore t ica l t rends in hand ling qua l i t i es wi th the veh i -c l e g a in p a r am e te r ch an g es d u r in g f l i g h t f o r b o th k in e s th e t i c an d h a r d w i r em an u a l co n t r o l m e th o d s . T o a t t a i n o p t im ized k in e s th e t i c co n t r o l , h e r emus t be s t r ingen t cons t r . a in t s imposed on the th rus t l eve l and mome nt ofi n e r t i a . H a r d w i r e c o n t r o l s m o r e e a s i l y o p t i m i z e d , s i n c e w o a d d i ti o n a lp a r a m e t e r s a r e a v a i l a b l e f o r a d j u s t m e n t : r o t a t i o n c o n t r o l l e r s e n s i t i v i t yg e a r r a t i o , Ks, n d t h e d i s t an ce f r o m th e t o t a l c en t e r of g r av i t y t o t h e g im -bal point. In the handl in g qual i t ies opt imiz at ion, the approa ch would be tocen t e r t o t a l p a r am e te r v a r i a t i o n d u r in g f l i g h t n ea r t h e b o t t o m of t h e cu r v ean d t h u s r ed u ce t h e t o t a l p a r am e te r v a r i a t i o n f r o m s t a r t of burn to end ofburn.

109a

z 7

21

- C O O P E R P I L O TP I N I O N S CA LE A S S U M E D- - U R N T I M E- KINESTHETI c CONTROL-- HA RD W I RE CONTROL---- HARDWIRE CONTROL WITH K ~ ~ A D J U S T E DURING FLIGHT

- .S Y S T E M S T A B ILITY PARAMETER VALUES

F i g u r e 10. - C o m p ar i s o n of Kines thet ic and Hardwire Handl ing,Qual i t ies Opt imizat ion Capabi l i ty

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Guidance and Navigat ion. - A s t r o n g a t t em p t w as m ad e t o e s t ab l i s hthe feas ib i l i ty of s imple op t ica l dev ices fo r a t t i tude re fe rence and lo r fo rg u id an ce . T h e p r o b l em s a s s o c i a t ed w i th t h e s e d i s p l ay s i n c lu d e v i s i b i l i t yl imi ta t ion s , keep ing the v i sua l r e fe rence in the p i lo t ' s f i e ld of v iew th roughth e l a r g e p i t ch a t t i t u d e ch an g e , c r o s s co u p l i n g b e tw een v i s u a l an d co n t r o lax e s , ap p r ec i a b l e e r r o r b ec au s e of r o u g h n es s of t h e l u n a r h o r i zo n , an d d i s -p l ay s r eq u i r i n g t h e p i l o t ' s a t t en t i o n f o r i n t e r p r e t a t i o n an d l an d m ar k i d en t i -f i c a t i o n . A z im u th r e fe r en ces w e r e n a rr o w ed o e it h e r h e su n o r s u r f acel a n d m a r k s .N e i t h e r ,h o w e v e r ,wa s found tobeadequa te h roughout he14-days tay t ime .Thesecons idera t ionsresul ted ina p r e f e r e n c e f o r at h r ee - ax i s , g y r o - d r iv en a t t i t u d e i n d i ca to r d i s p l ay .

A s y s t em m ech an i za t i o n st u d y w as p e r f o r m ed t o e st ab l i s h t h e w e ig h tpena l t i es as soc ia ted wi th the var ious sys tem concep ts .G u i d a n c e e r r o r a n a l y s i s w a s c o n d u c t e d s t a t i s t i c a l l y , u s i n g e r r o r

s o u r ce m ag n i tu d es t h a t a r e r ep r e s en t a t i v e of s im p le s y s t em m ech an i za t i o n swi thou t a h igh leve l of to le ranc e con t ro l . Such es t imate d e r ro r e f fe c t s o nL E S S o r b i t u n ce r t a in t i e s a r e l l u s t r a t ed i n T ab le 1. Nominalcondi t ionsw er e 3 - s t ep b o o s t p r o f i l e t o 60 n m o r b i t , T / W o = 0. 3 , an d co n s t an t t h r u s t .

T h e m a n u a l s t e e r i n g e r r o r e s t i m a t e s a r e b a s e d on d a t a f r o m 27 r u n srece nt ly ma de on the kines thet ic control s imulat ion at NASA-LRC.

When s ta t i s t i ca l ly combined to p rov ide th ree s tandard dev ia t ion (3u)e r r o r s i n r es ul ti ng LESS o r b i t s , t h e k i n e s t h e ti c a n d h a r d w i r e m o d e s w e r efound to p rov ide marg ina l ly acce p tab le o rb i t a l acc urac ies in t e rm s of avo id -in g l u n a r im p ac t . T h es e r e s u l t s a r e b e l i ev ed t o b e s l i g h t l y co n s e r v a t i v e i nr e g a r d t o t h e d o m i n a n t e r r o r s o u r c e s , p e n d i n g r e s u l t s of f u r t h e r s im u la -t ion es t ing a t NASA-LRC. F igure 1 1 s h o w s t h e e f f ec t on m in im u m a l t i t u d ea c h i e v e d a s a r e s u l t o f s t e e r i n g e r r o r s e n c o u n t e r e d . T h e m a r g i n a l c o n d i -t i o n s h o w n w i th s o m ew h a t co n s e r v a t i v e e r r o r e s t im a t e s m ay b e im p r o v edw i th f u rt h e r d a t a , a s n d i ca t ed . U n ce r t a in ty o r d ev i a ti o n b e low h e d e s i red6 0 - n m a l t i t u d e i s p lo t t ed a s a f u nc t io n of t h e m a in e r r o r s o u r ce - m an u a lc o n t r o l s t e e r i n g e r r o r . T h e m i n i m u m a l t i t u d e f o r r e n d e z v o u s a l l o w s f o rthe CSM to descend even lower wi th sa fe ty fo r phas ing maneuvers .

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TABLE 1 . - E F F E C T O F INDIVIDUALERRORSOURCES7r r o r S o u r c eMagnitude(3 -1I T h r u s t /W e ig h t IT h r u s t V e c t o r P o i n t i n g E r r o r sT h r u s t v e c t o r a l i g n m e n t v e r s u s v e h i c l e

( f ixed gimbal) or ef fect of cg un ce r-ta in ty (g imbaled)

M a n u a l s t e e r i n g e r r o r sKines the t icH a r d - w i r eStabi l i ty augmentedAutopilot

S t e p p r o f i l e a t t i t u d e m a n e u v e r r a t ee r r o r s

K in es th e t i c an d h a r d - w i r eStabi l i ty augmented

Thrus t Ign i t ion and Cutoff E r r o r sManual ignition and cutoff t iming

e r r o r sAV m e t e rEngine ta i loff impulse

4. 36%

0 . 4 "1 . 3 "1 . 1 "0 . 4 "0. I "

*2 . 4 5 " 1s e c*O . 54 a 1s e e

1. 0 s e c0 . 033%Negligible

6 0 - n mIn jec t ion Orb i t

Alt i tudeU n ce r t a in t i e s

(30-121 n m

1 3 n m41 n m35 n m1 3 n m3 n m

1 9 n m7 n m

12. 5 n m5. 5 n m

60 . ( 6 0 - N MA R G E TR B I T ) , L U N A RU R F A C EMIN F O RR E N D E Z V O U S

P O T E N T I A LW I T HR E D U C E DE R R O R S

0 0.5 1.0 1.5 2.0M A N U A LS T E E R I N GE R R O R D E G R E E S )

F i g u r e 11. Effect of T h r e e - S i g m a S t e e r i n g E r r o r son Minimum Al t i tude13


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T A B L E 2 . - WEIGHT BREAKDOWN - TYPICALHARDWLRE CONTR OL VEHICLE"

ComponentS t r u c t u r eGuidance and con t ro lE l e c t r i c a l s y s t e mEngine,gimbal ,andmountingR eac t i o n co n t r o l s y s t emP r o p e l l an t s y s t emP r e s s u r i z a t i o n s y s t e mBeacon and VH F t r an s p o n d e rDock ing mechan ism

Vehic le d ry weigh tC r e w , PLSS, su i t sRes idua ls and he l ium gas

Burnout weightP r o p e l l an t

G r o s s w e ig h t

Weight ( lb)5 6 . 057 .530. 040 . 020. 074. 041. 025. 020. 0

364. 5750. 0

13 . 51128 . 01160. 02293 . 5

F ig u r e 1 3 . LESS HardwireCont ro lConf igura t ionWith Visual Sight Guidance

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T h e i n e r t i a s f o r t h i s h a r d w i r e c o n t r o l v e h i c l e c o n c e p t r a n g e f r o m3 50 s lu g - f t2 in i t i a l ly to ap p ro x im a te ly 1 2 5 s lu g - f t2 . I n e r t i a s v a r i ed f ro m400 t o 8 0 0 s lu g - f t2 in i t i a l ly to th e 1 0 0 to 2 00 r a n g e at burnout in the s tudy .Gro ss we ig h t s v a ry f ro m ab o u t 2 1 0 0 p o un d s to 2 5 00 po u nd s fo r th e LESSv er s io n s , d ep en d i n g u po n th e e f f i c i en cy of th e en g i n es an d a sce n t p ro f i l e se m p l o y e d .C o r r e s p o n d i n gp r o p e l l a n tw e i g h t s r e 1000 pounds nd1600 pounds.

S u r f a c e o p e r a t i o n s . - T i m e - l i n e a n a l y s i s s h o w s t h a t a min imu m of45 m i n u t e s i s r e q u i r e d f o r o n e a s t r o n a u t t o u n l o a d , d e p l o y , a n d m a k e apre l imin ary chec kou t of the LESS. Fi gu re 1 4 i l l u s t r a t e s a p o ss ib le u n lo ad -in g co n cep t , a s su min g LESS s to r ag e o n Quad I of th e LM /EL M. Arm s an dc a b l e s a s s u r e a s t r o n a u t s a f e t y . T h e p r o t e c t i ve c o v e r c a n b e u s e d a s a s ledt o m o v e t h e LESS t o t h e t a k e o f f a r e a , s o m e 25 f e e t f r o m t h e L M / E L M . T h ev eh ic l e can b e d ep lo y ed a f t e r l an d in g on a co n t in g e n cy b as i s o r it can b e l e f t= to wed on th e L M/E LM u n t i l n eed e d .

A two -h o u r p r ep a ra t io n an d ch eck o u t p e r io d i s r eq u ir ed b e fo re anab o r t . Th e LESS t an k s a r e fu e led , u s in g sp ec ia l f i t t i n g s on LM ascen t t an kd r a i n s ( a m i n o r c h a n g e ) . B a t t e r y a n d g y r o p a c k a g e s a r e l o a d e d f r o m t h eL M s t o r a g e , g u id a n c e s a l i g n e d , s y s t e m s a r e c h ec k e d , a n d ba c k p a c k s a r er e c h a r g e d f r o m t h e L M .

A concep t u t i l iz ing a c lu s te r of e igh t ex is t ing Apol lo R C S p u l se mo d eengineshasconf igura t ion ,con t ro l ,andavai lab i l i tyadv ant age s. A view ofsuch a veh ic le i s seen in f igure 15 .

/F i g u r e 14. Lower ingLESS

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F i g u r e 15 . - LESS Fl ight Conf igurat ionLunar f ly ing appl icat ion - The LESS can be adapted to perform long-

range ,su r face- to - sur face , wo-man , ly ingmiss ions .C h an g es o h eLESSfor th i s opera t ion inc lude p rov is ions fo r eng ine th ro t t l ing , add ing land ingg e a r , s t r e n g t h e n i n g t h e s t r u c t u r e f o r landing oads , and adding a lon g-ra nget e l eco m m u n ica t i o n r e l ay p ack ag e . D es ig n c r i t e r i a w e r e ap p l i ed f r o m th er e c e n t P h a s e B Lunar Flying Vehicle S tudy (NAS9-9045) . F ig u r e 16 i s atypical conf igurat ion for such a vehicl e us ing a s ingle throt t led engine. Anat t r ac t ive a l t e rna t ive concep t cou ld u t i l i ze a c lus t e r of pulsed RCS engines(not shown).

The adapted LESS l o n g - r a n g e f l y e r ( L E S S / L R F ) i s c a p a b l e of a ranger ad iu s of f r o m 4 0 t o 6 0 nm using 1200 to 1600 pounds of pro pel lan t (s iz ed fore s c a p e m i ss i o n s ) . T h e s e o r d e r - o f - m a g n i t u d e n c r e a s e s in r an g e ,co m p ar edwith that of the smal ler lunar f ly ing vehic les , should provide subs tant ia lexplorat ion capabi l i ty . It wouid combine re la t ively long range w ith the safetyof shor t f l igh t t imes . An a t t r ac t ive po ten t ia l fo r improv ing mis s ion sa fe tycould be achieved by using it a s a r e s c ue v e h ic l e fo r a r o v e r o r a n o t h e r f l y e r ,and a s a r eco n n a i s s an ce v eh i c l e f o r f u tu r e l an d in g s i t e s .

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... . . - ... .... .. .


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F i g u r e 16. - Lo n g -R an g e F ly e r Ver s io n of LESSCONCLUSIONS

Th e s tu d y r e su l t s sh o w th a t t h e b as i c LESS co n cep t of a s i m p l e s y s t e mf o r e s c a p e of two men to a s a f e o r b i t i s f e a s i b l e . A d d i t i o n a l c o n c l u s i o n s a r ea s fo l lows:

1. S imp le man u a l co n t ro l mo d es may su f f i ce .2. S imp le b o o s t p ro f i l e s a r e accep tab le .3. R e s u l t i n g o r b i t a l e r r o r s a r e a c c e p t a b l e f o r s i m p l e c o n t r o l

co n cep t s , b u t sh o u ld b e co n f i rmed b y fu r th e r s imu la t io n t e s t in g .4. In i t i a l g u id an ce d a ta can b e ca lcu la t ed fo r LESS b y Miss io n

C o n t r o l C e n t e r a n d t r a n s m i t t e d v i a L M / E L M u p d a t a l i n k .5. C S M - a c t i v e r e n d e z v o u s a n d d o c k i n g r e q u i r e s n o C SM c h a n g e s ,6 . P r e s e n t C SM e n e r g y b u d g e t i s ad eq u a te .7. PLS S l i f e t ime of 4 h o u r s maximum is not exceeded.8. One man can dep loy and se t up LESS .

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9. Stowage of LES S on LM /ELM is poss ib le .10. L M / E L M c h a n g e s f o r d e f u e l in g a r e m i n i m a l .1 1 . LESS ad ap t s w e l l t o a l t e rn a te miss io n s .

ADDITIONAL RESEARCH RECOMMENDATIONS

Aero n au t i c s ( In c lu d in g Sp ace F l ig h t Sy s tems)

1. P e r f o r m f e a s i b i l i t y t r a d e o f f a n a l y s i s of LESS a d a p t e d t o r e s c u em i s s i o n s , u n m a n n e d s a m p l e r e t r i e v a l - t o -o r b i t m i s s i o n s , o r b i t a ls h u t t l e m i s s i o n s , l o g i s t i c s l a n d e r m i s s i o n s , e x p e r i m e n t l a n d e r ,an d fu tu r e l an d in g s i t e r eco n n a i s san ce to en su re max imu m sy s temversa t i l i ty and u t i l i ty .

Bio technology and Human Research

1. A d d i t i o n a l s i m u l a t i o n d a t a a r e n e e d e d f r o m f l i g h t - t y p e a n d f i x e d -b a s e - t y p e s i m u l a t o r s t o e s t a b l i s h t h e p r o b a b i l i t y of s u c c e s s f u lm i s s i o n s w i t h s i m p l e m a n u a l s t a b i l i t y a n d c o n t r o l m o d e s f o r t h eLESS. T h e s e d a t a r e q u i r e s t a t i s t i c a l t re a t m e n t t o a s s u r econfidence.

2. D a t a a r e l a c k i n g on p o s s i b l e p e n e t r a t i o n of s p a c e s u i t s b yp a r t i c l e s w h e n c r e w m e n a r e o p e r a t i n g i n t h e e x h a u s t p l u m e ofCSM R C S je t s . A l so , p ro p e l l an t ab so rp t io n b y su i t s co u ldcausc tox ic con tam inat ion af te r CSM entry . A v a c u u m t e s t i n gp r o g r a m m a y b e r e q u i r ed i f a r a p i d e s c a p e s y s t e m d e v e l o p -ment hould ecom e a r ea l i ty . -

3 . Th e l i m i t s of v i s ib i l i ty u n de r lu n a r v i ewin g co n d i t io n s a r e n o tw e l l e s t a b l i s h e d , p a r t i c u l a r l y a g a i n s t t h e b r i g h t lunar s u r f a c eb a c k g r o u n d . S p e c i f i c d e s i c n a t e d e x p e r i m e n t s m a y b e n e c e s s a r yi n e a r l y A p o l l o m i s s i o n s t o p r o v i d e d e f i n i t iv e d a t a .

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- , ..._ , ._ __ . - . . . .""

E l e c t r o n i c s a n d C o n t r o l

1. R e n d e z v o u s P r o g r a m 38 or i t s equ iva len t in the Apol lo gu idancc .comp uter cou ld be de le ted (no longer necess ary) by NASA-MSC.An ev a lu a t io n sh o u ld b e mad e to see if t h i s p r o g r a m c a n b ere t a in ed fo r p o ss ib le u se wi th th e LESS.

M a t e r i a l s a n d S t r u c t u r e s

1 . R e se a rc h on co l l ap s ib le t an k s i s d e s i r a b l e t o d e t e r m i n efeas ib i l i t y of s uch a co n cep t f o r -LESS an d o th e r ap p l i ca t io n sw h e r e i n t e m p o r a r y e m p t y s t o r a g e m u s t b e t i g h t l y c o n f i n e d . F o rLESS th i s co n cep t wo u ld ease th e LM/ELM s to rag e p ro b lem.

2. If a v e r y r a p i d e s c a p e s y s t e m d e v e l o p m e n t w e r e t o b e c o m e ar e q u i r e m e n t , it m a y b e d e s i r a b l e t o p e r f o rm d y n a m i c s a n a l y s e st o d e t e r m i n e t r a d e o f f s a n d f e a s i b i l i t y of p o s s i b l e l o c a ti o n s f o rs to wag e of th e LESS ab o a rd LM o r ELM . Th e lo ca t io n s a r e onQuad I o r IV b u t wi th in R C S j e t imp in g e men t a r ea , o r o n to p ofr e a r d ec k of d escen t s t ag e .

NuclearSystems (None)

P r o p u l s i o n a n d P o w e r G e n e r a t i o n

1. Cluste red Apollo RCS e n g i n e s o p e r a t i n g i n t h e p u l s e m o d e a p p e a ra t t r a c t i v e a n d h a v e b e e n c o n s i d e r e d f o r b o t h lunar f ly ing veh ic leand LESS ap p l i ca t io n s . W h i le ap p a ren t ly co mp lex , h e co n cep tp r o m i s e s d i s t i n c t a d v a n t a g e s i n t e r m s of p a c k a g e c o m p a c t n e ss ,r ed u n d an cy .g u id an ceaccu racyp o ten t i a l ,ea r lyav a i l ab i l i t y ,an dp r o v e d s a f e t y . T h e c o n c e p t m e r i t s s p e c i a l c o n s i d e r a t i o n i n f u t u r es tu d ie s .

lunar escape systems part 2

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