Astronaut and System Performance During Gemini EVA

8/7/2019 Astronaut and System Performance During Gemini EVA

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m .

BELLCOMM, INC.*

SUBJECT: Ast ronau t and Sys tem Per formanceDuring Gemini EVA - Cas e 340 DATE: November 1, 1966FROM:D.B. HoffmanA.N . K o n ta r a to s

ABSTRACT

R e s u l t s of the Gemini EVA program h a v e s u g g e s t e dt h a t ma n' s f u n c t i o n a l pe r fo r ma n ce i n w e i g h t l e s s n e s s may b es e v e r e l y l i m i t e d .d a t a a r e a n a ly z e d, a n d d i s c u s s e d . i n t h e l i g h t of env i ronmenta la n d sys tems c o n s t r a i n t s .

I n t h i s p ap er , t h e a v a i l a b l e ph y s i o l o gi c a l

T hi s a n a L ys i s r e v ea l ed . t h a t t h eu n r e s t r a i n e d a s t r o n a u t h a d t o work h a r d e r t o per form t h e samet a s k i n a w e i g h t l e s s e nv ir on me nt t h a n on e a r t h .t h ec a n b e o v er l oa d ed a t h e a t o u t p u t s e q u i v a l e n t t o t h o s eprod.uced b y a man i n a p r e s s u ri z e d s pa ce s u i t w al ki ng a t o n lyone m i l e p e r h ou r, t h e r e f o r e a l mo s t a s s u r i n g s a t u r a t i o nd u r i n g E1,'A.s h o ul d i n c r e a s e m an ls e f f i c i e n c y a nd u t i l i t y du r i n g f u t u r e EVA.

However,h e a t e xc ha ng e c a p a c i t y o f t h e Gemini s p a c e s u i t s y st em

Recommendations a r e made which, i f ' implemented,

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BELLCOMM,I N C .SUBJECT: Astronaut and System Performance DATE: November 1, 1966During Gemini EVA - Case 340

FROM: D. B. HoffmanA. N. K o n t a r a t o s

MEMORANDUM FOR FILE

INTRODUCTIONThe importance of EVA for t he fu tu re o f manned spacef l i g h t ne ed s l i t t l e e l ab o r at i on . Yet two of t h e f o u r EVA a t t e m p t sby U . S . a s t r o n a u t s were ended prematurely because of c o n d i t i o n sw h i c h b e c a m e p h y s i c a l l y i n t o l e r a b l e . A v a i l a b l e p h y s i o l o g i c a l

t r i a l h a v e i n d i c a t e d tha t l i f e u nd er t h e s e c ir cu m st an c es was,a t l e a s t , s t r e n u o us . S i n c e t h e p h y s i o l o g i c a l r e s p on s e o f t h ea s t r o n a u t d u r i n g EVA r e l a t e s to h i s o p e r a t i o n a l e f f i c i e n c y ,s p e c i a l a t t e n t i o n must be d e vo te d to u n d e r s t a n d i n g t h e c a u s e sof t h e Gemini d i f f i c u l t i e s . *

d a t a f r o m t h e o t h e r t w o U.S. space walks and t h e s i n g l e U.S .S .R . '.

In view of t h e more th an 2000 hours combined U . S . andU.S.S.R. o r b i t a l e x p e r i e n c e , t h e d i f f i c u l t i e s e n co un te re d d u r in gEVA should not be cons ide red to be t h e r e s u l t of s o m e i n t r i n s i ci n t o l e r a b i l i t y of l i f e to s pa ce f l i g h t . The e x p l a n a t i o n m us t b es ou gh t i n s t e ad i n l i m i t a t i o n s e x i s t i n g i n t h e s pa ce s u i t system,t h e o p e r a t i o n a l p r o c ed u r es , t h e m i s s i o n p l an n i ng , or t h e e a r t hb as ed s i m u l a t io n e i t h e r i n d i v i d u a l l y o r c o l l e c t i v e l y .

The purpose of t h i s memorandum i s to a t t e m p t to a n a l y z ethe problem and to recommend remedial hLeasures.RESULTS OF PHYSIOLOGICAL INVESTIGATIONS

T h e p h y s i o l o g i c a l data o b t a i n e d d u r i n g FVA which area v a i l a b l e to us a r e summarized i n T a b l e I. O f s p e c i a l i n t e r e s ta re t h e h i g h s u st a i ne d h e a r t r a t e s , - v e n t i l a t i o n r a t e s a nd t h ep h y s i c a l s e n s a t i o n s ( f a t i g u e , s we at in g, e t c . ) e xp er ie nc ed i n a l lEVA t r i a l s . These m a n i f e s t a t i o n s , a s expla ined be low, appearto be a t t r i b u t a b l e to a combined mechanical and thermal s t r e s s( h i g h work l o a d p l u s l i m i t e d ea a b i l i t y of th e EVA l i f e s u p p o r tsys tem to remove heat and water? upon which i s probably super -imposed an emotional component .

MSC i s p r e s e n t l y r e p a r i n g a p o s i t i o n p a pe r on e x t r a -v e h ic u la r . a c t i v i t y (EVAP..,


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B E L L C OMM,I N C . - 2 -

The i n f l a t e d s p a c e s u i t impai r s per formance and a d d sto t h e m e t a b o l i c e x p e n d i t u r e d u r i n g t h e p e r f o r m a n c e of normalt a s k s . T h i s i s due to p h y s i c a l i n t e r f e r e n c e , l i m i t e d b e nd in gc a p a b i l i t y of t h e t h i g h and knee r e g i o n s , r i g i d i t y of t h e wais t ,and to t h e e f f o r t to overcome t h e s u i t r e s i s t a n c e to f l e x u r ec a u s e d b y t h e d i f f e r e n t i a l g a s p r e s s u r e . * A s a r e s u l t , e v e nt h e mere bending of t h e e x t r e m L t i e s a n d the maintenance of suchpo s t ur e can be s t r enu ous . For example , a g r e a t d e a l of p h y s i c a le f f o r t was r e q u i r e d by Gordon to keep h i s l e g s g r i p p i n g t h eAgena for t e t h e r i n g o p e r a t i o n s d u r i n g t h e G e m i n i 11 f l i g h t .

A s s e en i n T a bl e 11, t h e r a t e of h e a t p r o d u c t i o n , am ea su re of p h y s i o l o g i c a l e f f o r t , i s g r e a t l y i n c r e a s e d w h e n ap r e s s u r i z e d s p a c e s u i t i s worn dur ing an ope ra t i on a s comparedto t h e r a t e o b ta i ne d d u ri n g t h e same opera t ion w i t h t h e s u b j e c tun su i t ed . For example , dur ing normal ly m i l d e x e r c i s e (0 .8 mphon a t r e a d m i l l ) , t h e pr e se n ce o f t h e i n f l a t e d Gemini s p a ce s u i twou ld have r equ i r ed t he equ iva l en t of abou t 8 4 p e r c e n t of th et o t a l working c a p a c i t y of t h e EVA l i f e suppor t sys t em (1400BTU/hr nominal, and 2000 BTU/hr. f o r p e r i o ds of s h o r t d u r a t i o n ) * * .Under cond i t i ons of more s t r e n u o u s e x e r c i s e , i t s nominal work-ing capac i t y wou ld h a v e been exceeded.

A s r e p o r t e d b y t h e a s t r o n a u t s , t h e work l o a d r e q u i r e dd u r i n g EVA was f a i r l y s t r e n u o u s , a nd e a r t h b as ed s i m u l a t i o n sf a i l e d to p r o v i d e t hem w i t h t h e n e c e s s a r y e x p e r i e n c e . Theu n r e s t r a i n e d a s t r o n a u t n o t o nly ca n n o l o n g e r u t i l i z e h i s bodywe igh t for mechan ica l advan t age du r ing t ask per formance i nw e i g h t l e ss n e s s , b u t h e a l s o e x p e r i en c e s f o r c e s of r e a c t i o n whichmake h i m l o s e h i s dynamic s t a b i l i t y . C o nt in u al s t r i v i n g tom a i n t a i n h i s body p o s i t i on du r ing t a s k pe r fo rmance f : u r t he ri n c r e a s e s h i s e n er g y e x pe n di t ur e .* * * Thus, t h e i n h e r e n t l i m i t a -t i o n s of t h e s p a c e s u i t s y s t e m p l u s t h e l a c k of adequa t e p ro -v i s i o n s of r e s t r a i n t ( h a n d h o l d s , f o o t h o l d s , h a r n e s s e s , p o s i t i o n -i n g d e v i c e s , e t c . ) are r e s p o n s i b l e f o r i n c r e a s i n g t h e a m o u n t ofw o r k r e q u i r e d f o r e f f e c t i v e p er fo rm an ce i n w e i g h t l e ss n e s s . I n a d d i t is t r e n u o u s an d l e n g t h y pre-EVA p r e p a r a t i o n s c o ul d a c c e l e r a t e t h eo n s e t of t h e o bs er ve d p h y s i o l o g i c a l m a n i f e s t a t i o n s . A s t ro n a utGordon, f o r example, noted t h a t he was t i r e d e v e n b e f o r e h e l e f tt h e s p a c e c r a f t .

I n t h e p a r t i c u l a r ca se of GT-9, t h e ELSS @Ex trav ehic ularL i f e Suppor t Sys tem) evapora to r / condense r cou ld no t keep pace

*Current A pol l o s pa ce s u i t c o n fi g u ra t io n s a r e a n t i c i p a t e dto r e du c e t h i s p ro bl em . P e r t i n e n t i n v e s t i g a t i o n i s c u r r e n t l yund.erway a t MSC.** Pr es en tl y MSC i s e v a l u a t i n g t h e t he rm al c h a r a c t e r i s t i c s oft he Apo l lo backpack . Tests comple t ed i nd i ca t e a c a p a b i l i t y forhan d l i ng a nomina l t he rma l l oa d o f 1600 BTU/hr f o r 3 h r s and thermt r a n s i e n t s b e t w e e n 3,000 t o 4,000 BTU/hr for s e v e r a l m i nu t es .

***This effect i s no t expec t ed to b e p r e s e n t d u r i n g the Apollol u n a r EVA s i n c e t h e re q ui re d s t a b i f i t y w i l l probab ly be p rov idedb y l u n a r g r a v i t y .


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BELLCOMM,I N C . - 3-

w i t h t h e t h e r m a l l o ad and p r ev en t f o g g i n g of t h e s pa ce s u i tv i so r? Fu r thermore fogg ing was p robab l y enhanced by t h e h i g hr e s p i r a t i o n r a t e s o b s e r v e d d u r i n g EVA. T h i s b r e a t h r a t e c o u l dh a v e s a t u r a t e d t h e g r e a t e r p a r t of t h e t o t a l o x y g e n f l o w to t h eh el me nt , s i m u lt a n e ou s l y a c c e l e r a t i n g t h e c o n d e n s a t i o n p r o c e s sto a l l o w f o g g i ng a t n or ma l v i s o r o p e r a t i n g t e m p e r a t ur e s a n da l s o i n h i b i t c l e a r i n g of t h e v i s o r . **

I n t h e p a r t i c u l a r c a s e o f GT-11 , o v e r e x e r t i o na p p a r e n t l y c a u s e d o v e r l o a d i n g o f t h e EVA l i f e s u p p o r t s y s t em .T h i s c o u l d h av e l e d to t h e o b s e r v ed f u n c t i o n a l d . eg r ad . a t i o n( - f a t i g u e an d v i s i o n i mp ai rm en t c au sed. b y e x ce s s i v e s w e a t i n g ) ,n e c e s s i t a t i n g e a r l y a b o r t o f t h e EVA p h as e .F i n a l l y , one must a l s o c o ns i d e r t h e p o s s i b i l i t y ofa n umber o f m i s ce l l a n eo u s f a c t o r s w hi ch co u l d h av e c o n t r i b u t e dto t h e o b se rv ed d i f f i c u l t i e s , na mely:

1. The a d d i t i o n of t h e c h e s t p a c k a d ds to t h e p h y s i c a lin t e r f e r en ce p roblem du r in g EVA.2. High mot iva t ion cou ld . obscu re t h e p e r c e p t i o n ofdis co mfo r t and impending s t r e s s .3. E mo ti on s a s a r u l e w or se n t h e p h y s i o l o g i c a lm a n i f e s t a t i o n s a nd t h e r e f o r e c o ul d p l a c e a d d i t i o n a ldemands o n t h e s p ace s u i t s y s t em .4. The p u l m o n a r y o x y g en p a r t i a l p r e s s u r e of t h e a s t r o n a u t

d u r i n g EVA cou ld d rop to a subnormal l e v e l i n t h eev en t of a bu i l dup i n H20 vapor p r es su re and C02. ***The combinat ion of a low oxy ge n p a r t i a l p r e s s u r e a n da n enhanced ambien t C 0 2 c a n i n c r e a s e p u l s e a n dr e sp ir a: io n r a t e s , d e c r e a s e t h e p h y s i o l o g i c a l r e s e r v e sf o r mu sc ul ar a c t i v i t y and l e a d to p r em a t u r e ex h au s t i o n .H y p e r v e n t i l a t i o n i t s e l f c an a l s o l e a d to s i m i l a rp h y s i o l o g i ca l r e s p o n s es and p e r fo r man ce d ec r emen t sth rough p rog ress ive pu lmonary C02 dep le t ion .

*There i s e vi de nc e i n d i c a t i n g t h a t t h e ev ap o r a t o r / co n d en s e rperformance was degraded due to d r y o u t o ccu r r i n g s o m e t i m e d u r i n gt h e m i ss i on , p re sum ab ly a t o r n e a r t h e t ime of i n g r e s s , D r y o u ti s a t t r i b u t a b l e to h i g h e r t h a n a n t i c i p a t e d m e t a bo l i c l o a d .p ro bl em a s e v i de n ce d i n GT-11. However, t h e ph ys ic a l ba se s fori t s o r i g i n a r e s t i l l p r e s e n t .

**The u s e of a n an t i - f og compound has e l im in a t ed t h e f o g g i n g

***For t h i s r e a s o n t h e t o t a l p r e s s u r e p ro vi de d b y t h e A p o l l ob a ck p ac k h a s b e en i n c r e a s e d r e c e n t l y t o 3.9+ 0 . 1 p s i


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BELLCOMM, I N C . - 4-.5 . R u ss ia n d a t a i n d i c a t e t h a t m od er at e p h y s i c a l a c t i v i t yd u r i n g s p a c e f l i g h t c a n c a u s e h i g h p u l s e r a t e s , s w ea t in gand e a r l y f a t i g u e . A cc or di ng t o R u ss i an p h y s i o l o g i s t s(Gazenko e t a l . ) t h e s e o b s e r v a t i o n s s u g g e s t s h i f t s i n t h e

r e g u l a t i o n a n d d y n a m i c s o f t h e c i r c u l a t o r y s ys te m t h a tc o u l d a f f e c t p e rf o rm a nc e . However, p h y s i o l o g i c a lr e a c t i o n s t o m i l d e x e r c i s e i n G e m i n i m i s s i o n s h a v e f a i l e dt o p ro du ce simllar e f f e c t s .CONCLUSIONS A N D RECOMMENDATIONS

I t i s c o n c l u d e d t h a t t h e p o o r p e r f o r m a n c e o f t h e Geminia s t r o n a u t s i n EVA i s r e a d i l y e x p l a i n e d b y t h e c o m b i n a t i o n s of al i f e s u p po r t sy st em w i t h low work load margins , t h e r e s t r a i n tf rom t h e i n f l a t e d s u i t , a nd a n u n e x p ec t e d ly s t r e n u o u s work l o a ddue t o z e r o G e f f e c t s .oxygen p a r t i a l p r e s s u r e , h y p e r v e n t i l a t i o n r e s po n s e an d c a r d i o v a s c u ls h i f t s - may a l s o b e i nv ol ve d b u t a r e n o t c o n s id e r e d to b e ofp r imary impor t ance . With a view to i n s u r i n g e f f e c t i v e EVA opera-t i o n s f o r A po llo a nd AAP, t he fo l l o wi ng r ecommendat ions a r e made :

O th er f a c t o r s - h i g h mot iva t i on , emot ions ,

1. T ho se of t h e " o t h e r f a c t o r s ' ' t h a t c o u l d b e c h ec ke d b yg r o u n d s i m u l a t i o n a t h i g h work l oad shou ld b e s os t u d i e d i f such a n e f f o r t i s n o t underway. The f i r s tr e a s o n a b l e o p p o r t u n i t y f o r f l i g h t t e s t would ap pe a r t ob e t h e S-IVB work shop (AS- 209 a n d s u b s e q u e n t r e n d e z v o u s ) .No g r e a t u r g e n c y i s s e e n for e a r l i e r f l i g h t . Theproposed expe r iment pay loa ds sh ou ld be r ev iewed f o rcove rage o f t h e s e f a c t o r s .2. Work l oad marg ins for s p a c e s u i t - l i f e s u pp or t systemsmu st b e r e ev a lu a te d . The r e l a t i v e f l e x i b i l i t y of t h eApol lo Block I1 s u i t may w e l l o f f e r a d e q ua t e m a rg inf o r 1/6 G o p e r a t i o n ; c u r r e n t MSC s t u d i e s s ho ul d p r e s sf o r h i g h work l o a d s L m u l a t io n s .3. If p o s s i b l e , a d d i t i o n a l EVA e x e r c i s e s o v e r a n d a bo v eGT-12 should . be perfomned b e fo re t h e l u n a r l a n d in g top r o v i d e o p e r a t i o n a l e x p e r i e n c e an d d e m o n s tr a t e t h eadequacy o f t h e A po ll o s p a c e s u i t s y s t em .4. A backpack w i t h n o m i n a l a n d t r a n s i e n t t h e r m a l c h a r a c t e r -

i s t i c s a de qu at e to accommodate t h e f u n c t i o n a l w o r kc a p a c i t y of a t y p i c a l a s t r o n a u t s h o u l d b e c o n s i d er e dfor AAP.5. I t s ho u ld be recog nize d. t h a t z e r o g r a v i t y a c t i v i t i e sa r e n o v el a nd r e q u i r e b o t h s t u d y b y t h e e n g i n e e ra n d l e a r n i n g b y t h e a s t r o n a u t .

a . A v a r i e t y of means t o g i v e t h e a s t r o n a u t s t a b i l i t ya n d l e v e r a g e ( h a n d h o l d s , h a r n e s s e s, f o o t h o l d s ,e t c . ) m u s t b e t r i e d to f i n d w hic h a r e m os t


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SELLCOMM,I N C . - 5-

e f f i c i e n t . T h i s s h o ul d b e g i n on Gemini 1 2 andc o n ti n u e ( e ve n i n t r a v e h i c u l a r l y on e a r l y Ap ol lof l i g h t s ) a s n ec es sa ry to suppor t o f f -nomina lm i s s i o n s ( e . g . , e x t r a v e h i c u l a r c r e w t r a n s f e r ) .It should. be a m a j or e f f o r t i n t h e AAP.b . EVA op er at io n proced ures should . be reschedu led . toa l l o w " a c c l i m a t i z a t io n " of t h e a s t r o n a u t an dp r o v i d e o p t i o n a l w o r k- r e s t p e r i o d s . T h i s s h o u l dp a r t i c u l a r l y a pp ly to t h e s c h e d u l i n g of l u n a rs u r f a c e a ct i v i t i e s .

6 . S u b s t a n t i a l d i f f e r e n c e s i n a s t r o n a u t r es po ns e a r eo b s e r v ed . A s a cont ingenc y measure i t may b e p o s s i b l eto s e l e c t a s t r o n a u t s f o r t h e Apol lo l u n a r s u r f a c emi ss io n who have shown l o w er m e t ab o l i c o u t p u t s i nEVA an d / o r s i m u l a t i o n s .

ACKNOWLEDGEMENTT h i s r e p o r t be ne fi te d. m a t e r i a l l y from d i s c u s s i o n s w i t h

M r . H.S. Browns te in and Dr. F.B. Benj amin of NASA/MM. S p e c i a lthanks a r e a l s o due t o Messrs. G.T. O r r o k , P.R. Knaff andF . G . Allen of Bellcomm.

A t t a chmentT a b l e s I and I1

A . N . K o n t a r a t o syp-7I ..-----*

copy to(See n e x t p a g e )


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BELLCOMM,I N C .

copy t oMessrs. L.O. Anderson - NASA/RBHF.B. Benjamin - NASA/MMJ . B o l l e r u d - NASA/mH.S. Brownste in - NASA/MMT.A. George - NASA/MTXH. H a l l - NASA/MTXS.H. Hubbard - NASA/MGOD .W . J e n k i n s - NASA/SBW.L. Jones - NASA/FBT.A. Keegan - NASA/MA-2D.R. Lord. - NASA/MTXE . J. McLaughlin -NASA/MMK.F. Okano - NASA/MARL. R e i f f e l - NASA/MA-6R.F. Trapp - NASA/RBAJ . H . Turnock - NASA/MA-4S . P . Vinograd - NASA/MML.N. Werner - NASA/MTXC.A. B e r r y - MSC/DAL.F . Die t le in - MSC/DBR.S. Johnston - MSC/ECE. Michels - MSC/DB2G.M. AndersonT.A. Bottomley, J r .D.R. HagnerP.L. Havens te inW.C . H i t t i n g e rB.T. HowardD.B. JamesP.R. KnaffJ . Z . MenardI .D . NehamaG.T. OrrokT.L . PowersI . M . RossP.F. Sennewald.T.H. ThompsonR.L. WagnerA l l Members, Division 1 01C e nt r al F i l eDept. 1023L i b r a r y


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Astronaut and System Performance During Gemini EVA