Apollo 9 30 Day Failure and Anomaly Listing Report

8/13/2019 Apollo 9 30 Day Failure and Anomaly Listing Report

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30-DAY FA1LURE

: I NAS P - T f l - X- 70000 APOLLO 9:

- MSCyPT-R-69-13bI C s A N D S PA C E A D M I N I S T R A T I O N

APOLLO 9AND ANOMALY L ISTING REPORT

ii.DAY N74 72469- .i F I L U R E AND A N O f i A L Y L I S T X I G REPORT (NASA):: 43 p.. 00/99 16728

Unclas

DISTRIBUTION ND REFERENCINGThi s paper i s no t su i tab le far genera l d i s t r ibu t ion or re fe renc ing .on ly in o ther work ing cor respondence and documents by par t i c ipa t i ng organ iza t ions .

I t may be re fe renced

M A N N E D S P A C E C R A F T C E N T E* * z H O I J S T O N . T E X A St igV APRIL 1969D


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.... -- . , ,MS C-PT-RL 69- i 3

APOLLO 930-DAY FAILURE AND ANOMALY LISTING REPORT

PREPARED BY

Mission Evaluat ion Team

APPROVED BY

Go rg e M . LowManager, Apollo Sp ace cr af t Program

NATIONAL AERONAUTICS AND SPACE ADMINISTRATIONMANNED SPACECRAFT CENTER

HOUSTON, TEXASApril 1969


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INTRODUCTION

T h i s r e p o r t c o n t a i n s a d i s c u s s i o n of t h e s i g n i f i c a n t a no ma li es n o t eddur ing t h e Apo llo 9 mission . The d is cus s io n of th es e i tems i s d i v i d e di n t o t h r e e m a jor areas:government-furnished equipment . The s t a t u s of th e open anomalies w i l l b emainta ined i n t h e Anomaly S ta tu s Report .

command and s e r v i c e modules , lu na r module, and

COMMAND AND SERVICE MODULESPROPELLANT I S O L A T I O N VALVE CLOSURES

Fol lowing se pa ra t i on from the S-IVB, t h e c rew r e p o r t e d a c o n t r o lproblem which had l a s ted f o r about 1 2 minutes d u ri ng t h e t r a n s p o s i t i o np e r i o d . The crew f i r s t n o t i c e d a l a c k of c a p a b i l i t y f o r t r a n s l a t i o n t ot h e l e f t .dary p rop e l l an t i s o l a t io n valves and the quad D secondary valves were i nt h e barber p o le o r c l o s e d p o s i t i o n ( f i g . 1).and t h e system performed normally th e re af te r . These va lv es had beenopened du r ing f i n a l checks p r i o r t o l aunch and were v e r i f i e d t o be openby t h e c rew j us t p r io r t o sep a ra t ion f rom th e S-IVB.

The p o s i t i o n i n d i c a t o r f l a g s f o r t h e q uad C primary and secon-The valves were opened

Propel lan t usage and quad tempera ture data showed that all f o u rquad C valves were clo sed and th a t quad D w a s performing normal ly beforet h e crew opened th e p rop e l l an t i so l a t io n valves, Propellant may be sup-p l i e d f rom e i t h e r t h e p ri ma ry or secondary tanks and only t h e secondarytank va lves were c l o s e d on quad D .a f t e r t h e va lves were opened ve r i f i ed normal ope ra t ion of quad C .Angular r a t e d a t a t r a n s m i t t e d s h o r t l y

The f o l lo w in g p o s s i b i l i t i e s e x p la i n t h e v a l v e c l o s u r e s :1. Momentary, in ad ve rt en t switch act ua t i on by th e crew - This i s

n ot v e ry l i k e l y , as bo th t h e Commander and t h e Command Module P i l o t madea curs o ry check o f t he pane l a f t e r t he y exchanged seats , a n d n e i t h e r n o t e dany d i sc repanc ies .

2. Momentary sw itch cl os ur e caused by contam inat ion - N o p a r t i c u -l a t e contaminat ion was found i n the swi t che s .3. E l e c t r i c a l t r a n s i e n t s - This has been d isco unte d because oft h e power req ui re d .4. Reduced l a t c h i n g f o r c e - T h e p r o p e l l a n t i s o l a t i o n v a l ve s i n t h e

command module reaction control s y s t e m a r e i d e n t i c a l t o t h os e i n t h e s e rv -i c e module system. To determine whether t h e magnet ic la tc h i ng fo rc e of


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. . d

t h e valv es cou ld have been d et e ri o ra te d , t h e val ves on command modules103 and 104 and tho se f rom sev e ra l ground t e s t s were checked . Resu l t scompared favorably wi th or ig in a l acceptance t e s t d a t a on t h o s e p a r t i c u -lar v a l v e s .

5 Valve clo sur e caused by mechanical shock a t s e p a r a t i o n o f t h ecommand and se r v ic e modules from th e a da pt er - Shock t e s t s were r un on as e r v i c e m odule r e a c t i o n c o n t r o l s y st em v a lv e t o e s t a b l i s h t h e l e v e l ofshock t h a t would be neces sary t o cause a normal valve t o c lo se . A c r o s ss e c t i o n a l v iew o f t h e v a l v e i s shown i n f ig u r e 2 . R es ul ts o f t h e t e s ti n d i c a t e t h a t a shock of about 80g could cause a v a l ve t o c l o s e . Thes hoc k r e s u l t i n g from t h e py ro t ec h n i c c h a rg e s u s e d t o s e p a ra t e t h e commandand se rv i ce modules f rom t h e ad apte r m a y have been between 40 and lOOg( a na l ys e s t o r e f i n e t h e s e v al ue s a r e i n p r o g r e s s ) .

The m o s t p rob a bl e c a u s e o f t h e i n a d v e r t e n t c l o s u re w a s t he shock a tsep a ra t ion from th e adap te r . Apparent ly , t h e shock i s of s uf f i c i en t mag-n i t u d e , d i r e c t i o n , a nd l o c a t i o n t h a t i t c o u l d h av e c a us e d t h e s e v a l v es t oc l o s e . The p a r t i c u l a r v al v e s t h a t mi gh t c l o s e a r e a fu n c t i o n o f t h e no r-m a l l a t c h f o r ce o f t h e v al v es i n q u e s t io n a nd t h e a t t e n u a t i o n a nd d i re c -t i o n o f t h e s ho ck from t h e s e p a ra t i o n at t h e l o c a t io n of t h e valve.

The Apollo Operations Handbook ( A O H ) w i l l b e changed t o i n s u r e t h a tt h e cr ew check t h e p ro p e l l a n t i s o l a t i o n v a l v e s i mme d ia te ly a f t e r separa-t i o n and th a t the y reopen any valves which m a y have closed.

This anomaly i s open.

S C A N N I N G TELESCOPE SHAFT D R I V E PROBLEMThe degrees drums o f t h e t e l e s c o p e s h a f t a n gl e c o u n t e r on t h e o p-

t i c s c o nt r ol p a n el f r o ze at 64 degrees on the f i r s t day o f t h e miss io n .The te nth s drum co nt inu ed t o r o t a t e ( f i g . 3) . During an al ignment oft h e i n e r t i a l measurement unit on th e second day , t h e s ha f t d r ive mechan-i s m s to pp ed i n t e r m i t t e n t l y . I n some c a s e s , t h e u n i v e r s a l t o o l h ad t o b eused t o ope ra te t he op t i c s manual. ad j us t sc rew t o f r ee th e mechanism.The dr ive mechanism pe rs i s te d i n jarmning i n t er m i t te n t ly u n t i l t h e f i f ' t hday, a f t e r which t h e p rob lem d i sappea red .

The opt ica l u n i t assembly w a s removed from t h e spa ce cr af t , and e le c-t r i c a l d r iv e t e s t s showed t h a t t h e d riv e mechanism w a s f r e e . When t h eu n i t w a s d i sassembled , t h e p i n f rom th e t en ths drum of t he coun te r gen -eva mechanism driv e ( f i g . 4 w a s found wedged i n a s p l i t g ea r on t h e d r i ves h a f t o f t h e one s p ee d r e s o l v e r i n t h e t e l e s c o p e g e a r box.

The problem re su l te d from an out -of- to leranc e con di t io n on t h e holei n t o which t h e p i n w a s p r e s s - f i t . The co un te rs f o r command modules 106


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and su bsequ ent and lu na r modules 5 and subsequent w i l l b e r e p l a c e d w i t hu n i t s which have be en s p e c i f i c a l l y in s p e c t e d f o r t h i s c o n d i t i o n . T h i sanomaly i s c losed .

LOSS OF AUTOMATIC CRYOGENIC HYDROGEN PRESSURE CONTROLD ur in g t h e f l i g h t , t h e a u to ma ti c p r e s s u r e c o n t r o l s y st em i n t h e hy-

d rogen t ank s fa i l ed . The log ic of t h e c o n t r o l s ys te m ( f i g . 5 ) i s sucht h a t t h e p re s s u r e s w it ch es i n bo th t a nk s must c l os e i n o rd er f o r t h eh e at e rs t o be ac t iva t ed ; however , opening of only one pressure swi tchw i l l d e a c t i v a t e t h e h e a t e r s . The f i r s t i n d i c a t i o n o f f a i l u r e w a s n o t e da t 93 h o u rs , s h o r t l y a f t e r t h e i n i t i a l u nd oc king , when t h e h e a t e r s weren o t a u t o m a ti c a l ly a c t i v a t e d ( f i g . 6 ) . A t a p pro x ima t el y t h e t i m e o f t h ef i n a l lunar module undocking, a l l hydrogen ta nk h ea te rs came on and pr es -s u r i ze d t h e t a n k s t o about 2 70 p s i a , w hich r e q u i r e d t h a t t h e h e a t e r s bet u rn e d o f f ma n u a l l y .

A s a r e s u l t o f t h e a u to m at ic p r es s u re c o n t r o l s ys te m f a i l u r e , t h ehydrogen p ressu re w a s co nt r o l l ed us ing t h e manual mode throughout t her e ma in d er o f t h e mi s s io n .

S in c e t h e f i r s t f a i l u r e ( f a i l u r e t o t u r n o n ) would ha ve r e q u i r e done p r e s s u re s w i t c h t o f a i l open and t h e s ec on d fa i lu re ( f a i l u r e t o t u r no f f ) would hav e r e q u i r e d t h a t b o t h pressure swi t ches f a i l c l o s e d , t h eswi t ches can be ru l ed ou t . The most p robab le cause fo r t h e f a i l u r e s w a san i n t e r m i t t e n t c o n d i t i o n i n t h e motor or i t s c o n t ro l c i r c u i t ( i n c lu d i n gt h e power l i n e , g ro un d, and t h e t e rmi n a l b o a rd fo r 16-gage p i n s ) r e s u l t -i n g from t h e undocking shock ( see f i g . 5 . Six teen -gage t e r mi na l boa rdshave been t h e source of i n t e r n i t t e n t c o n t a c t d u ri n g v e h i c l e g ro un d t e s t s .

No co r r ec t iv e ac t ion w i l l b e t a k e n f o r A p ol lo 1 0 ; t h e t a n k p r e s s ur e sc an b e c o n t r o l l e d ma nu ally by e i t h e r t h e h e a t e r s or t h e fans i f t h e a ut o-mat ic sys tem f a i l s .

This anomaly i s c losed .

ERRONEOUS DOCKING PROBE INDICATIONSDuring in i t ? . dL undocking , t h e Command Module P i l o t p l a c ed t h e pro be-

e x t e n d / r e l e a s e - r e t r a c t s w it ch t o e x t en d / r el e a s e , and t h e veh ic l e s begant o s e pa r a t e , n d i c a t i n g r e l e a s e o f t h e p rob e -e x te n d l a t c h . However, t h ev e h i c l e s d i d n o t p h y s i c a l l y u n l a t c h L l n t i l t h e t h i r d a t te m p t. I n d i ca t i on sf o r c e t o e f f e c t p h y s i ca l s e p a r at i o n .

&I^^& L L . L l . _ - ^a l c bust, t , l h t : b w L l r c I 1 w w u u u hel d pos i t io i i lofig eiio-&i foi- a segai-atiiig


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The second d i sc repancy occu r red p r io r t o t h e l una r module dock ingmaneuver, when t h e Command Module P i l o t pl ac ed t h e s wit ch i n t h e r e t r a c tp o s i t i o n i n p r e p ar a t io n f o r d oc ki ng .showed ba rbe r po le , i nd ica t in g th a t t h e p robe w a s not cocked f o r dock-i n g . T h i s i s fu r t h e r e vi de nc e t h a t t h e e x t e n d / r e l e a s e - r e t r a c t s w i t chw a s n o t a c t u a t e d f o r a s u f f i c i e n t t i m e t o a l l o w t h e d oc ki ng prob e t of u l l y ex tend . Cycl ing th e docking mechanism produced t h e proper grayd i s p l a y i n d i c a t i o n .

I n t h i s p o s i t i o n , t h e d i s pl a y

The design w i l l a l lo w t h e l a t c h e s no t t o cock du r ing undocking i ft h e r e l e a s e mo t o r s a r e n o t e n e rg iz ed s u f f i c i e n t l y l on g f o r t h e l a t c h e st o s p r in g back t o pr op er a t t i t u d e for cocking.uncocked ( la tch es- l ocke d) con fig ur a t i on which e x is t s when docked.

The s ys te m r e t u r n s t o t h e

The Apollo Operations Handbook (AOH) h a s b e e n chan ged t o i n c l u d e t h erequi rement f o r h o l di n g t h e e x t e n d / r el e a s e - r e t r a c t s w it c h i n t h e e x te n d/r e l e a s e p o s i t i on u n t i l p h y s i c al s e p a ra t io n .


MULTIPLE COMMANDS NOT ACCEPTEDA t approximately 1 9 hours , t h e sp ace c ra f t would no t re spond t o mul-

t i p l e u pl in k real-time commands. Ten ho ur s l a t e r , t h e c rew c y c l e d t h epower sw itc h t o t h e command system, r e s t o r i n g no rmal o p era t i o n ( f i g . 7 ) .The f i r s t of multiple commands w a s re ce iv ed by t h e command re ce iv er ; how-e v e r , a message accepta nce puls e w a s n o t t r a n s m i t t e d t o t h e ground r e c e iv -e r , w hich i n t u r n s en ds a s i g n a l t o t h e g round t r a n s m i t t e r t o s en d t h enex t command. The ground ov er ri de fu nc ti on w a s used on sev e r a l occas ionst o t ra ns mi t th e next command; however , t h e sp ace cra f t s t i l l d i d n o t re-spond. The problem exis te d over numerous ground s ta t i on s and a l s o w a sexper i enced once p r e f l i gh t ; consequen t ly , it h as b ee n i s o l a t e d t o t h ef l i g h t h ardw are.t h e d i sc r ep a nc y .by Apr i l 2 5 . However, no co rr ec t i ve ac t i on i s a n t i c i p a t e d for space-c r a f t 1 0 6 .

A s y e t , no conclu sion can be drawn as t o t h e ca us e ofT e s t i n g o f t h e s p a c e c r a f t h ardw are i s t o be completed


ENTRY MONITOR SYSTEM FAILUREThe en t ry mon ito r syst em s t y l us d id no t con t inuous ly cu t t h rough

The acce le romete r ou tpu t o f t h eh e emuls ion on t h e s c r o l l a ss em bl y.e n t r y m onitor d r i ve s t h e s t y l u s t o s c r i b e t h e a c c e l e r a ti o n ( g ) h i s t o r y


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ver sus ve lo ci ty . The emulsion on t h e mlar s c r o l l f i l m i s cured andk ep t i n a dry atmosphere by e n c l o si n g t h e s c r o l l assernbly i n s i d e a s e a l e dcas e under one a tmosphere of dry neon gas t o main ta in th e pr op er c ons is-t e n c y of t h e em ul si on ( s e e f i g . 8 ) . The c h a r a c t e r i s t i c s o f t h e e mu ls io nchange i f mois tu re i s a b so rbe d , c a us in g t h e s u b s t a nc e t o h a rd e n .

A l e a k w a s found i n t h e scroll assem bly p o s t f l i g h t ; t h e leak woulda ll ow t h e c as e t o b r e a t h e m o is tu re i n s i d e . A l e a k - t e s t e d s c r o l l assem-b l y , w i t h a f i n e r s t y l u s p o i n t w hich w i l l p e n e t r a t e h a rd e r e mu l s i on s , a n ds e v e r a l o t h e r m in or mo d i f i c a t i o n s w i l l b e i n s t a l l e d i n A pollo 10 .

This anomaly i s closed .

INDICATED SERVICE PROPULSION PROPELLANT UNBALANCED uring t h e t h i r d f i r i n g o f t h e s e r v i c e p ro p ul s io n e n g i ne , t h e r e were

e i g h t master alarms from t h e p ro p e l l a n t u t i l i z a t i o n a nd g ag i ng s ys t e min d i ca t i ng an excess ive p r op e l l an t unbal.ance ( f ig . 9 .A l l t h e m a st er alarms a r e exp la in ab le . The f i r s t a r m was caused

by p r o p e l l a n t l e v e l i n t h e c a p a c i t i v e me as ur in g t u b e n o t r e a c h i n g t h es e t t l e d l e v e l s m n enough a f t e r s t a r t -u p . The nex t f i ve alarms, showni n f i gu r e 9 , r e s u l t e d f ro m an e l e c t r i c a l z er o b i a s i n t h e o x id i ze r meas-u r in g c i r c u i t a f t e r s to r age t ank dep le t ion . Thus, cont inuous alarms ont h e p r imary g ag in g s y s t em c au se d t h e crew t o s w i t c h t o t h e aux i l i a rysys tem , which employs po in t sens ors at d i s c re t e l e v e l s i n t h e ta n ks .

A l e g i t i m at e unbalance caused an alarm d u ri n g t h e a u x i l i a r y s ys te mo p e r a t i o n , as noted . Also, s w i t c h in g b a ck t o t h e p r ima ry s y s te m r e s u l t e di n a n ot h er l e g i t i m a t e a l a r m , even though th e ze ro b i a s ex i s t ed .

Mas te r alarms and cau t i on and warn ing i nd ica t io ns f rom th e p rope l -l a n t u t i l i z a t i o n and g a g in g s y s te m a r e n o t r e q u i r e d . C on se qu en tl y, t h e s ef 'unct ions have been cut from t h e s ys te m fo r s p a c e c ra f t 106 and subsequent ,as shown i n f i gu re 10 .

A c a l i b r a t i o n a nd a p p ro p r i a t e ad ju s tme nt w i l l be made d ur in g pre -f l i g h t s e r v i c i n g t o compensate for t h e z e ro b i a s a t ta nk cro sso ver . Ad-di t ional ly , procedures have been changed for t h e crew t o i g n o re t h e u nb al -ance du r ing t h e f i r s t 2 5 seconds of a f i r i n g t o a llo w s u f f i c i e n t t i m efor p r o p e ll a n t s e t t l i n g .

This anomaly i s closed.


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6MASTER ALARM DURI NG DOCKI NG

A master alarm wi thout a cau t ion and warning annunc ia to r occu r redco inc iden t w i th dock ing . No i n p u t w a s i d e n t i f i e d as b e in g i n t h e r an geof the caut ion and warning system at t h a t t i m e . The f a c t t h a t t h e a l ar mdid no t occur a t p h p i c a l c o n ta c t b ut d u r in g t h e h a r d d oc ki ng r u l e s o uts t a t i c d i s ch a rge b et we en t h e tw o v e h i c l e s a n d i n d i c a t e s a s h o c k - s e n s i t i v econ di t i on . The mast er alarm sys t em i s very s e n s i t iv e t o t r i g g e r s i g na l sand requi res only a 5-m icrosecond p u l s e t o i n i t i a t e an alarm. The cau-t i o n a nd w arni ng l i g h t s r e q u i r e a con t inuous inpu t t o i l l u m i n a t e . As h o c k - se n s i t iv e i n t e rm i t t e n t c o n d i t i o n i n one of about 60 i n p u t s c o u l dt r i g g e r t h e a l a r m .

The ca uti on and warning sy ste m has been removed or t e s t i n g t o d et er -mine whe the r any of t h e components are shock-sens i t i ve or whether anyo u t-o f -t o le r a nc e c o n d i t i o n e x i s t s .

During docking t e s t s a t t h e l au nc h s i t e , t h r e e u n e xp l ai n ed masteralarms were experienced on spa ce cr af t 106.t u a l c o n t a c t o f t h e lu na r module w ith t h e command and ser vi ce m odules.T h e re fo re , a recu r rence i s l i k e l y d u ri n g t h e A p oll o 10 miss ion . No cor-r e c t i v e a c t i o n i s a n t i c i p a t e d fo r A p ol lo 10 a t t h i s t i m e .

One w a s a s s o c i a t e d w i t h ac -


FUEL CELL 2 CONDENSER E X I T TEMPERATUREThe c o n de ns er e x i t t emp e ra t u re fo r f u e l c e l l 2 w a s o u t s i d e t h e n or -

m a l range (155 t o 165O F) on numerous occasi ons . This con di t i on w a ssimilar t o tha t observed on Apol lo 7. A n al ys is shows t h a t t h e t r a v e l o ft h e s ec o nd a ry c o o l a n t r e g e n e r a t o r b y pa s s v a l v e ( f i g . 11)w a s r e s t r i c t e dbetween approximately 4 and 10 percent bypass be tween 88 and 191 h o u r s .The condense r e x i t t empera tu re rema ined wi th in normal ope ra t i ng l i m i t sat all l o a d s a f t e r 191 hours . The load s a f t e r t h a t t i m e were r e l a t i v e l yhi gh , re qu ir ing normal bypass valv e modulat ion between 8 and 19 p e r c e n t .

Previous ground t e s t s and ana lys i s o f coo lan t d ra in ed from v ib ra t io nand f lu sh ing ope ra t ions o f o the r space c ra f t show t h a t coo lan t l oop con-t ,miinat ion bu i ldup i n t h e v a lv e c au se d t h e r e s t r i c t e d t r a v e l o f t h e by -pass va lve . Th i s con tamina t ion i s p re se nt i n t h e f o rmo g e l a t i n o u sp ho sp ha te s a nd /o r s o l i d p a r t i c l e s .

For Apollo 1 0 , t h e r a d i a t o r s w i l l b e v i b r a t e d a nd a volume exchangemade 30 t o 45 d ays p r i o r t o l au n ch ( t h e Ap ol lo 9 s p a c e c ra f t h a d o n l y avolume exchange 45 days p r i o r t o l a u n c h ) . An i n - l i n e change t o u s e t h e


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7block I bypass valve, which i s l ess s u s c e p t i b l e t o c o nt am i na n ts , h a s b ee nmade.


D O C K I N G SPOTLIGHT FAILED

The Command Module Pi lo t repor ted d ur in g t h e l i g h t in g check p r i o rt o r endezvous t h a t t h e dock i ng ( ex t e r i o r ) s p o t l i gh t on t h e s e r v i ce mod-u le d i d no t o per a te . Photographs of th e veh ic le dur ing rendezvous showedt h a t t h e l i g h t d i d n o t d e p lo y. The c i r c u i t b r e a k e r f o r de p lo y in g t h el i g h t w a s open at l aunch , as s p e c i f i e d , t o p r e v e n t i n a d v e r t e n t d ep lo y-m en t, a nd t h e b r e a k e r h ad n o t b ee n c l o se d p r i o r t o t h ? a t te m p t t o d ep lo yt h e l i g h t ( t h e crew c h e c k l i s t d i d not i n c l u d e c l o s u r e o f t h e b r e a k e r ) .O t her c i r cu i t s pow ered t h rough t h i s b r eak e r were e i t h e r r e du nd an t or weren ot u se d u n t i l l a t e r i n t h e m is si on . La te r , t h e b r e a k er w a s c l o s e d f o rope r a t i on o f t h e r i ght - hand crewman op t i ca l a l ignmen t s i g h t , and t h es i g h t i n s t a l l a t i o n o p e ra t ed p ro p er ly .

The c rew c hec k l i s t ha s been changed t o i nc l ude c l o s i n g o f t h e c i r -c u i t b r e a k e r p r i o r t o s p o t l i g h t deployment.


I NTERNAL FLOODLIGHT MALFUNCTIONSThe crew r epo r t e d t h a t t h r e e o f t h e s i x i n t e r n a l f l o o d li g h t s m a l -

fun ct i one d dur in g t h e miss io n. One became extremely hot and em it ted anodor.lower equipment bay fa il e d . The primary lamp cathode had completely dis -i n t e g r a t e d , n d i c a ti n g t h a t t h e l amp had been opera ted excess ive ly be-tween ful l dim and ful l br ig h t , which g re a t ly r educes t h e lamp l i f e andcauses a d io de t o f a i l .

P o s t f l i g h t t e s t i n g r ev ea l ed t h a t t h e p r im ar y l a m p i n t h e r i g h t

Because of a broken w i r e , t h e s econda ry lamp on t h e l e f t -hand couchwould no t opera te .

The lamp on t h e rig ht- han d couch was r epo r t ed t o be ex t reme l y hot.and em it t ed an odor . There w a s touch-up p a i n t on t h e lamp, and dur ingp o s t f l i g h t o p e r a t i o n , t h e touch-up p a i n t d i d emit an odor.emi t t ance w i l l b e e s t a b l i s h e d by t e s t s i n p ro g r es s .

The heat

Se7 rernl l s q s k;Z. T been che2?2g:ei e2 1\.>e11c 1 becsLlse cf s e Seycnda 100-hour l i m i t fo r t e s t and checkout. Lamp ope rat i on has been r e s t r i c t -e d i n t h e Test and C r i t e r i a Document t o t h e dim 2 po si t i on . This anomalyi s open pending complet ion of t h e heat t e s t s .


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J

aCOMPUTER RESPOPJSE TO DSKY ENTRIES

The crew repor ted two occasio ns i n which th e computer d i d not re-ceive and a c t upon d at a en ter ed through t h e d is p la y and keyboard assembly(DSKY). The f i r s t cas e involv ed a d i g i t a l a u t o p i l o t c o n f i g u ra t i o n changeb e fo re t h e s i x t h s e r v i c e p ro p u l s i o n maneuver. The d a t a r e q u i r e d t o i n -co rpor a t e t h e in t ended change were keyed in t o th e DSKY and observed on th eDSKY d is p la y . Depr essio n of t h e ENTER key w a s r e p o r t e d , b u t t h e a ut o-p i lo t con f igu ra t ion d id no t change. The second case occu r red du r ing as p a c e c r af t power-down pe ri od when Verb 46 ENTER, which dea c t iv a t e s t heau to pi lo t , was unsuc cessf u l . The two occurrences a r e d i f f e r e n t i n t h a td i f f e r e n t f a i l u r e or p r o c e du r a l e r r o r c h a r a c t e r i s t i c s w ould b e r e q u i r e dt o produce t he re po rt ed symptoms. A d e p re s si o n o f t h e ENTER k e y t r a n s -mits a ? - b i t keycode t o t h e compute r , which the n t ak es app rop r i a t e ac t ioncor respond ing t o t h e da t a p rev ious ly keyed in t o and d i sp l ay ed on t h e DSKY.A t t h e same t i m e , t h e computer cause s t h e DSKY t o blan k or change t o t h en e x t d i s p l a y i f unde r program co n tr o l. Depr essi on of t h e ENTER key w i l ln o t b l a n k t h e DSkT un less t h e p rope r keycode i s rec e iv ed by t he computer .Depression o f ot he r keys may blan k a l l o r pa r t of t h e DSKY, depending ont h e s i t u a t i o n i e . , a CLEAR key b l an ks t h e d a t a r e g i s t e r s , a VERB keyb lanks th e verb d i s p l a y , and a PROCEED ke y w i l l b l an k o r change t o t h en e x t d i s p l a y ) .the computer.

Al l r e q u i r e p ro p e r r e c e i p t o f i n fo rma t i o n an d a c t i o n by

In t h e f i r s t ca se , t h e dep ress ion o f t h e PROCEED key in s t ea d of anENTER would have caused t h e symptoms and re s u l t s rep orte d . In th e sec-ond c ase , i f a Verb 46 w a s keyed i n , on ly ano the r VERB key depress ionwould have blanked t h e DSKY withou t en te ri ng t h e d ata .i t y would be en t ry o f a verb which causes n o a c t i o n a t all o r a n a c t i o nwhich i s u n d e t e c t a b l e . Possib le verbs which f i t t h i s c a t e g o r y are V45E,V47E, V5 6 E, V66E, v 7 6 ~ , nd V86E.

Anothe r poss ib i l -

No hardware or sof twa re f a i l u r es t h a t could have caused th es e condi -t i o n s ha ve been i d e n t i f i e d . P ro ce du ra l. e r r o r s o f t h e t y p e d i s c u s s e d c o u ldhave caused t h e f a i l u r e con di t i ons . However , t h e crew con side rs it m-l i ke ly th a t such e r ro rs were made.


SURGE TANK SHUTOFF VALVEThe r e p re s s u r i z a t i o n o f t h e s u rge t a n k r e q u i r e d a n e x c e s s i v e l e n g t h

o f t i m e . Nomina l rep ressu r i za t ion w a s ach ieved when th e c rew rep os i t i one dt h e t a n k s h u t o f f v al v e . D ur in g t h e s y st ems d e b r i e f i n g , t h e crew s t a t e dt h a t t h e y b e l i e v e d no mec h an ic a l prob le ms e x i s t e d w it h t h e v a l v e b u t t h a t


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9the . decal marking w a s mi s a l i g n e d w i t h t h e valve d e t e n t p o s i t i o n . P o s t-f l i g h t , t h e v a lv e po s i t i o n s were checked and found t o be misa l igned by30 degrees . Spacec ra f t 106 has been checked for proper a l ignmen t .


D O C K I N G R I N G SEPARATION CHARGE HOLDER

One docking r i n g sep ar a t ion charge ho lde r w a s deformed and out ofi t s c h a n n e l, e x t e n d in g s e v e ra l i n c he s b eyo nd t h e p e r i p h e ry o f t h e externalt u nn e l s t r u c t u r e ( f i g . 1 2 ) .ny lon r i s e r l i ne s du r ing pa rachu te dep loymen t.

Such a conf igu ra t ion migh t foul or c u t t h e

The charge ho lde rs are t w o s e mi c i r c u l a r s t e e l r i n g s a t t a c h e d at onee nd w i th t h e o t h e r e n d f r e e . They normally rem ain i n a channel about ani nch deep on to p o f t h e rema in ing tunn e l s t ru c t u r e . Dur ing g round t e s t s ,t h e f ree end o f t h es e ho lde r s occas iona l ly came ou t o f t h e channe l butnever deformed t o t he ex ten t expe r i enced on Apo l lo 9 . I t i s not knownwhe the r t h e de fo rmat ion occu r red du r ing descen t or during recovery opera-t i o n s .

A r e t a i n e r s p r i n g d es ig n ( f i g . 13) has demons t ra t ed t h a t du r ing sep -a r a t i o n , it w i l l r e t a i n t h e c ha rg e h o l d er wi th ou t t h e lunar module at tached.This des ign w i l l be i n c o rp o ra t e d on s p a c e c r a f t 106 .

This anomaly i s c l o s e d .

LUNAR MODULE

DESCENT PROPULSION REGULATOR MANIFOLD PRESSURE DROP

Dur ing th e f i r s t 30 seconds of t h e f i r s t d e sc e nt en g in e f i r i n g , t h ed e s c e n t p ro p u ls i o n h e l iu m r e g u l a t o r ma n i fo l d p r e s s u re d ec ay ed t o 180 p s iand r e c o v e re d t o a normal value of 240 p s i a . Al l t e m p e r a tu r e , p r e s s u r e ,and f l o w i n d i c a t i o n s s u b s t a n t i a t e a p l ug g e d h e a t e x ch a ng e r i n t h e s u p er -c r i t i c a l h eli um s ys te m ( s e e f i g . 1 4 ; t h e p l ug g in g c l e a r e d d u r in g t h ef i r i n g ( see f i g . 15 , as i n d i c a t e d by t h e p r e s s u r e r i s e i n t h e s u p e r c r i ti c a l h e li um t a n k a n d t h e r e t u r n t o no rm al r e g u l a t e d p r e s s u r e .

After t h e s u p e r c r i t i c a l he lium s e r v i c i n g at t h e l aunch complex, t h et a n k f i l l and vent quick-d isconnects are p u rg e d w i t h h e l iu m t o i n s u r eL - A L - a:------- - --,. A-. 1 . ~ 4 ~ ~ ~.,.:..,.. -onnrra r n ~ --..-,-.- ~ i: . .i s s u p p l i e d from t h e same r e g u l a t o r t h a t i s s up po se d t o m a i n t a in t h e man -i f o l d p r e s s u re above 5 p s i g .V I I ~ I , ~ i i c U I C . R - C L L J C . V I I ~ ~ C L I J rr UAJ UGLV LG v ~ r u g w p p ~ u . LUL p u ~ ULLLIYJL


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1During the LM-3 s e r v i c i n g , t h e p r e s s u r e must have d r opped t o ze r o ,

a l lowing a i r t o be drawn in to t h e manifold by condens ing out t h e incom-i n g a i r i n t he s u pe r c r i t i c a l he li um t ank hea t exchange r. T es t s have shownt h a t d ro pp in g t h e m an i fo l d p re s s u re t o z e r o f o r a bo ut 30 minutes w i l l al-low air t o be cryo-pumped i n t o t h e man if o ld t o t h e t ank hea t exchanger ,where i t w l l f r e ez e and b lock t h e hea t exchanger . The f r ee z in g proce sst r a n s f e r s h ea t i n t o t h e s u p e r c r i t i c a l h el iu m t a n k , c a us in g a p r e s s u r e r i s eof about 90 p s i , v e r y s imi l a r t o what occu r r ed du r i ng t h e LM-3 top-of f( s e e f i g . 1 6 ) . If no a i r were in t rod uced , t h e t ank pres sure would be ex-p ec te d t o r i s e 1 0 p s i or l e s s .

The ground support equipment has be en modif ied f o r Apollo 10 ands ubs equent t o i s o l a t e t h e pu rge s ys tem from t h e man i f o ld p r e s s u r e con-t r o l s ys te m. F u r t h er c o nt in u ou s p r e s s u r e r e c o r d i n g w i t h p r o p e r s c a l i n gw i l l be employed on t h e man ifold. Add itio nal equipment may b e sup pl ie dt o p ro vi de t h e c a pa b i l i ty t o t e s t f o r b l ockage o f t h e t ank hea t exchange r.Ser vic ing procedures us in g th e new ground suppo r t equipment conf ig ura t io nw l l be demo nstrated. The new equipment and se rv ic in g proc edure s w i l lt h e n b e s hi pp ed t o t h e l au nc h s i t e fo r Apol lo 1 0 .


SUPERCRITICAL HELIUM PRESSURE DECAY

The p r e ss u re i n t h e s u p e r c r i t i c a l h el iu m t a n k f o r t h e d e sc e nt p r o-pul s ion sys tem began decaying a t 2 . 9 ps i / h r i mmed i a t e l y a f t e r shutdowno f t h e f i r s t d e sc e nt e n g in e f i r i n g and c o n t in u e d t o decay u n t i l s t a g i n g .Because o f he a t t r a n s f e r i n t o t h e t a n k , t h e p r e s su r e s h o u l d a l w a y s i n -c re ase under no- flow condi t ions ( f i g . 1 7 ) . The pressure decay i s i nd i ca -t i v e of a leak of about 0 . 1 lb /h r f rom t h e he l ium system. Analys i s o f t h ed a ta i n d ic a t e t h e l e a k w a s u ps tr ea m o f t h e s o l e n o i d valve and probablyups tr eam o f t he s up e r c r i t i c a l he li um t ank hea t exchanger.

The f l i gh t con f i gu r a t i on o f he l ium t ank , s qu i b valve , b i m e t a l l i cf i t t i n g , and a s s o c i a t e d plum bing h as n o t b e en t e s t e d t o g e t h e r f o r re s p on s et o s qu ib v a lv e f i r i n g s ho ck ( f i g . 18) o t h e r t h an t h e LM-1 f l i g h t , whichshowed no sign of leakage. A t e s t i s be i ng r un o n t h e LM-4 f l i g h t con-f i gu r a t i on t o de te rmi ne w het her o r no t t h e components from t h e t ank t o t h ef ue l hea t exchange r have s u f f i c i e n t s t r en g t h marg in f o r t he r ma l v i b r a t i on ,and squib va lve f i r i n g shock .

The LM-3 s q u i b v al v e d i f f e r e d from t h e LM-4 c on fi gu ra ti on i n t h a tThe LM-4 f i t t i n g s are e x t e r n a l l y b ra z e d ( f i g . 19 .t h e LM-3 valve f i t t i n g s w ere i n t e r n a l l y b r a z e d , p r e v e n ti n g p r o p e r in s p ec -t i o n of t h e j o i n t .


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11T e s t i n g o n t h e LM-4 con f i gu r a t i on w i l l be completed about Apr i l 13.

I f a f a i l u r e o c cu rs or measured s t ress l e v e l s are excess ive , modi f i ca-t i o n s w i l l be in co rp or at ed on a second specimen. Thi s t e s t should becompleted about Apr i l 1 9 .


TRACKING LIGHT FAILURE

The t r a ck i ng l i g h t became i nope r a t i ve s ho r t l y a f t e r s t a g i n g . Pos-s i b l e c au se s are vo l t age b reakdown i n t h e f l a s h head assembly, breakdowni n t h e h i gh- vo lt age cab l e , component f a i l u r e i n t h e e l ec t r o n i c s package ,or vo l ta ge breakdown i n t h e pulse-forming network. Based on f a i l u r eh i s t o r y , b reakdown i n t h e pulse-forming network i s cons idered th e mostl i k e l y c au se of t h e f a i l u r e . T es t s a r e i n p r og re s s on a LM-4 t r a c k i n gl i g h t t o de te r mi ne w he ther t ha t con f i gu r a t i on can s t an d v i b r a t i on , s hock ,vacuum, and th er ma l s t r e s s of t h e LM-4 miss ion. If t h e u n i t f a i l s t h emi s s ion s i mu l a t i on , a t r a c k i n g l i g h t w it h a modif ied pulse-forming net-work now b ei ng manu fac tur ed w i l l be i n s ta l l ed i n LM-4.has improvements which should el im ina te vol ta ge breakdown under t h e f l i g h tenvironment .

The modi f i ed un i t


PUSH-TO-TALK SWITCHES INOPERATIVEThe Lunar Module P i l o t ' s push- to-ta lk swi tche s , lo ca ted on th e um-

b i l i c a l and on t h e a t t i t u d e c o n t r o l l er , were i n o p e r a t i v e a t about 89 hours .The Lunar Module Pi lot used the VOX mode f o r t r a n s m i t t i n g f o r t h e remain-d e r of lu na r module opera t ions . Fa i lu re of bo th swi tches i s not p robable .The common pa th on e i t h e r s i d e o f t h e sw i tc h e s i n c l u d es s w i tc h c o n t a c tson t h e a u d io s e c t i o n , c o n ne c t or s , a nd d i o de s i n t h e s i g n a l p r o c e s so rassembly.w i r e ) i n t h e common w i r e t o t h e p a r a l l e l p u sh -t o- ta lk s w it c he s .The problem w a s probably caus ed by a d i s c o n t i n u i t y ( b r o k e n

The pu sh -t o- ta lk mode of communication i s i s o l a t e d from t h e VOX modeof communication. I n ad di t i on , swi tching t h e backup push- to- talk modew i l l bypass most of t h e common wiring where t h e f a i l u r e may have occurred.A change f o r t h e Apollo Operations Handbook w i l l inc lude mal func t ion

t r o u b l e s h o o t i n g pr o ce d ur es t o b e used i f t h e p r ob lem r ecu r s .


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ABORT GUIDANCE WARNING LIGHT

During th e t h i r d manning , a cau t ion and warn ing alarm occur red a ta c t i v a t i o n o f t h e a b o r t g u id a nc e sy s te m.t i o n means tha t one o f t h e fo l lowing cond i t ions i s p r e s e n t :The ca ut ion and warning indica -

1. The 1 2 -V dc power suppl y vo l ta ge i s out of l i m i t s .2 . The 28-v dc power supply vo l ta ge i s o u t o f l imi t s .3. The ac power s upp ly vol ta ge i s ou t o f l i m i t s .4. T h e a b o r t e l e c t ro n i c s fa i l s a s e l f - t e s t .5 An o ve rt em pe ra tu re e x i s t s i n t h e a b o r t e l e c t r o n i c s .6 . One of t h e mo n it o r in g c i r c u i t s ( i n s t ru me n t a t i o n ) o f t h e f i v e

previous items has mal funct ioned .'The spec i f i ca t ion l i m i t s f o r alarms a nd t h e o p e r a t i n g s p e c i f i c a t i o n

l i m i t s o f t h e pa r a met e rs h av e s u f f i c i e n t s p r e a d t h a t a n o u t -of - s p e c i fi c a -t i o n cond i t ion would have caused a mal func t ion o f t h e abo r t gu idance sys -t e m .

The most l i k e l y c aus e of t h e anomaly w a s e i t h e r a s h o r t e d o r b r o ke nw i r e between th e abor t e l ec t ro n ic s a ssembly and t h e s i g n a l c o n d it i on i nge lec t ron ics a ssembly 26 gage wires w i th se ve n s p l i c e s ) , a f a i l u r e w i th i na s i g n a l c o n d i ti o n i ng e l e c t ro n i c s a ss embl y, or a f a i l u r e i n t h e c au ti onand warning system.

The f i ve ab or t gu idance warn ing pa ramete rs i n LM-4 were measuredand v e r i f i e d t o b e w it h in s p e c i f ic a t io n l i m i t s , w i t h s u f f i c i e n t s e p a r a -t i o n b etw ee n t h e o p e ra t i n g l i m i t s and th e cau t ion and warn ing l imi t s .

T h i s anomaly i s c l o s e d .

NO I N D I C A T I O N OF TAPE RECORDER OPEMTING

The Lunar Module P i l o t r e p o r t e d t h a t t h e t a p e r e c o rd e r (d a t a s t o r -age e l ec t ro n ics a ssembly ) w a s not op er a t ing pr ope rly wi th t h e Lunar Mod-u l e P i l o t i n t h e VOX mode. A n al ys is of t h e t a p e i n d i c a t e s t h a t t h eCommander's au di o c e n te r w a s conf igu red fo r i n t e rcommunica t ions ( hotmi cro ph o ne ) , a nd t h e t a p e r e c o rd e r w a s runn ing con t inuous ly , as i t shou ldhave been . Review o f t h e vo ice reco rded ind ica t e s t h a t no anomaly ex i s t e d .


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13

A g r ay i n d i c a t i o n on t h e f l a g i s a p r o p e r o p e r a t i o n i n d i c a t i o n o n lyf o r t r a c k 1 o f t h e f o u r t r a c k t a p e . If no modulat ion i s present ont r a c k 1, t h e f l a g w i l l b e b a rb e r p o le w h i l e r e c o rd i n g on t h e o t h e rt h r e e t r a c k s .

The Apol lo Opera t ions Handbook has been changed t o c l ea r l y de sc r ib et h e o p e r at i o n of t h e f l a g i n d i c a t o r a s s o c i a t e d w i th t h e f o u r v o ic e t r a c k s .


B I N D I N G OF FORWARD HATCH AND FAILURF GF DOOR STOPThe crew rep or te d t h a t when th e forward ha tch w a s opened fo r extra-

v e hi c ul a r a c t i v i t y , i t t ended t o b ind on t op and had t o be pushed down-ward t o open it. Also, t h e d oo r would no t s t ay open . F igu re 20 showst h e p o t e n t i a l h a t ch i n t e r f e r e n c e p o i n t s t h a t c o u ld h av e c a us ed t h e bi nd -ing .

Inspec t ion on LM-5 showed t h a t t h e v e h i c l e f r o n t f a c e b l a n k e t aboveand a rou n d t h e h a t c h o pe ni ng pro t ru d e s be lo w t h e v e h i c l e f i x e d s t ru c t u r es h i e l d i n g ( i n an area where 0.250- inch c l ea ra nce shou ld e x i s t ) .t r u s i o n i s i n t h e p a th of and i n t e r f e r e s wi th t h e h at ch s h i e l d l i p .w i l l b e i n s p e c te d f o r s imi la r c o n d i t i o n s . C o r r e c t iv e a c t i o n w i l l be t orun a s t r i p o f t a p e b etw ee n t h e v eh ic le s t r u c t u r e and s h i e l d t o r e t a i n t h eb la nke t and p reve n t i t f ro m s ag gi ng i n t o t h e h a t c h o p en i ng .

This pro-LM-4

The door s top (snubber) i s a t t a ch e d t o t h e door a nd i s d es ig ne d t or i d e a g a i n s t a Velcro pa t c h on t h e f l o o r , t h e r e by h o l d i n g t h e d oo r open.The door s to p d id no t work i n f l i g h t . Floor s h i f t r e l a t i ve t o t h e doors t o p i n z e ro -g i s b e i n g s t u d i e d t o de te rmine whe the r t h e door s t op canp ro p e r l y r i d e on t h e V el cro p a t c h .


HIGH CABIN NOISE LEVEL

The n o i s e l e v e l i n t h e c a b i n w a s t o o h igh . The p r imary no i s e sou rceswere t h e c a b i n f a n s , g l y c o l pumps, and su i t compressors .ments were made on LM-8 wit h t h e gly col pumps and s u i t compressors opera t -ing . The wors t sourc e w a s found to be t h e gl yc ol pumps. The pumps coup lea c o u s t i c e ne rg y i n t o t h e g l y c o l l i n e s and t h e n t o t h e p r e s s ur e vesse l a tp e n e t r a t i o n p o i n t s .

Noise measure-

The p r e s s ur e v e s s e l t h e n a m p l i f ie s t h i s e n e rg y .


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1 4Fl e x i b l e c o u p l in g s a r e b e i n g s t u d i e d as a means of minimizing acous-

t i c coup l ing between t h e pumps and l i ne s . Tests w i l l be p e rfo rme d i n LM-8t o d et er mi ne t h e i r e f f e c t i v e n e s s . A change t o t h e Apollo Op era t ion s Hand-book has been made t o u se on ly one c ab in fan and th en on ly when c oo l ing i sr e q u i r e d .

No hardware change w i l l be made for Apollo 1 0 , as most o f t h e miss ioni s cond ucted with hel me ts on. Hardware changes are b e i n g c o n s i d e r e d f o rApollo 11, as t h e c rew w i l l b e r e q u i r e d t o s l e e p w h il e on t h e lunar sur-f a c e .


STRUCTURAL CONTACT AT S-IC SHUTDOWN

Data i n d i ca t e t h a t t h e l a t e r a l l oa d s in t ro d uc e d a t S-IC shutdownc a us e d t h e h el iu m d i f fu s e r f l a n g e on t h e d e s c e n t p ro p e l l a n t t a n k t o con-t a c t t h e s he et metal f l a n g e of t h e up pe r deck ( s e e f i g . 2 1 ) . Analysishas shown th a t t h e con tac t would not damage e i th e r th e upper deck she etme t a l f l a n g e o r t h e heavy d i f f u s e r f l a n g e or t a n k b o s s . Analysis a l s oshows t h a t th e tan k and plumbing a r e n o t o v e r - s t r e s s e d u n de r t h i s con-di t i on . The lower weight of LM-4, i n c o nj un c ti on w it h t h e s-IC expec tedshutdown condit ions, w i l l produce l e s s d e f l e c t i o n f o r A po ll o 1 0 t h a n w a sexper i enced on Apollo 9. F u r t h e r s t u d i e s are underway f o r Apollo 11weights and shutdown t r a n si e n t s .

This anomaly i s c l o s e d f o r A p ol lo 10 .

DATA ENTRY AND DISPLAY ASSEMBLY OPERATOR ERROR L IGHTThe d a t a e n t ry a nd d i s p l a y a ss embly o p e ra t o r e r ro r l i g h t was i l l u m i -

n a t e d f r e q u e n t l y d u r i n g t h e mis s i o n a nd ha d t o b e e x t i n g u i s h e d by d e p re s -s i o n of t h e CLEAR pushbu t ton . The dep ress ion of t h e bu t t on would b l ankt h e d i s p l a y . The o p e ra t o r e r ro r l i g h t would go o u t b u t w ou ld r e t u rn uponr e l e a s e o f t he CLEXR bu tt on . Four or f i v e d e p re s s i on s o f t h e b u t t o nwould b e r e q u i re d t o e x t i n g u i s h t h e l i g h t .

The mos t l i ke ly cause of t h e cond i t ion w a s a f a i l u r e o f a c o n t a c to f one o f t h e t wo s w it ch e s i n t h e CLEAR pushbut ton . A f a i l u r e o f t h eno. 1 c o n t a c t t o c l o s e would p r e v e n t t h e a b o r t e l e c t r o n i c s a ss embly fromr e c e i v i n g a CLEAR d i s c r e t e , w h il e t h e n o. 2 con tac t wou ld f unc t ion no r -ma l ly , causing t h e da t a en t r y and d i sp l ay a ssembly t o pe r form CLEAR opera-t i o n s , t h a t i s , b la nk d i sp l a y s , r e s e t o p e r a to r e r r o r l o g i c , e t c . Theabove condit ions re su l t i n t h e compute r rema in ing i n t h e r eadou t mode


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15

and, consequently , s ending SHIFT d i s cr e te s t o th e data e n t r y a n d d i s p l a yassembly.CLEAR mode w i l l caus e t he ope r a t o r error l i g h t t o b e i l l um i n at e d.The sending of SHI FT discre tes whi le the as sembly i s i n t h e

The two s w i t ches a s s oc i a t e d w it h t h e pa r t i cu l a r CLEAR bu t t on had ap r e f l i g h t h i s t o r y o f p r ob le ms.no t c l o s i ng s i mu l t aneous l y and / o r t he pus hbu t ton no t dep r e s s i ng f u l l y .The condi t ions i nv o lv e d w i th t h e p r e f l i g h t d i s c re p a n c i es w i l l be exp l o r edf u r t h e r . However, no change w i l l be made t o LM-4.

The problems co ns i s te d of t h e two switches


ASCENT PROPULSION HELIUM PRESSURE

At t h e s t a r t of t h e second a s cen t p ropu l s ion f i r i ng , t h e he l iump r e s s u r e t o t h e p r o p e ll a n t t an k s r e gu l at e d a t about 177 p s i a i n s t e a d o ft h e expec t ed va l ue o f 185 p s i a .s u r e i nc r eas e d from 176 t o 180 p s i a .A t 290 s ec on ds i n t o t h e f i r i n g , t h e p r es -

Four asp ect s of t h e problem m u s t be cons i de r ed :1. The lockup pressure w a s about 19 ps i a be f o r e and a f t e r t h e f i r -

i n g - This s a t i s f i e s t h e normal lockup of t h e p ri ma ry r e g u l a t o r i n l e g I ,i n d ic a t in g t h a t l e g I had a t leas t some f low capabi l i ty .

2 . The leve l o f r egula t ion dur ing f low w a s about 177 p s i a up t oabout 300 seconds - T his r egu l a t ed p r e s s u r e cou ld have been co n t r o l l edby e i t h e r t h e pr im ar y r e g u l a t o r i n l e g I1 or t h e p ri ma ry r e g u l a t o r i nl e g I if t h a t r eg ul a to r down-shi ft ed a round 8 p s i under flow condi t ions .

3. Dur ing t h e r egula ted f low per iod , th e r e gul a ted pres s ure droppedabout 1 p s i o ve r 300 seconds - T he cha r ac t e r i s t i c r egu l a t i on p r e s s u r e sdec r eas e w i t h a d e c re a se i n s u pp ly p r e s s u r e f o r t h e pr im ar y l e g I regu-l a t o r . I n 300 seconds , about a 1-ps i pr ess ure drop would be expec ted f o rt h i s r e g u l a t o r . On t h e o t h e r hand, t h e p ri ma ry r eg u l a to r i n l e g I1 hadi n c r e a s i n g r e g u l a t i o n p r e s su r e s w i th a decreas ing supply pres sure ofabout 1 p s i i n 3 seconds. These f a c t s sugges t th a t th e pr imary regu-l a t o r i n l e g I w a s c o n t r o l l i n g t h e f l ow up t o a bo ut 300 seconds .

4. A t about 300 seconds , t h e r egu la te d pre s sur e increa sed 3 t o4 p s i - This sugges t s a t l e a s t one of f our co ndi t ion s :a . The pr imary regulator i n l e g I w a s c o n t r o l l i n g ( w i t h a down-

downs hi ft i n r egu l a t i o n ) , and t h e down-shif t w a s p a r t i a l l y c o r r e c t e d .


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b .u p s h i f t i n r e g u l a t i o n . T h is i n d i c a t e s a m a lf u nc t io n i n t h e p ri m ar yr e g u l a t o r .

The p ri mary r e g u l a t o r i n l e g I1 w a s c o n t ro l l i n g a n d h ad a n

c . The p ri ma ry r e g u l a t o r i n l e g I1 w a s c o n t r o l l i n g , a nd t h ep ri ma ry r e g u l a t or i n l e g I s t a r t e d t o c o n t ro l b u t u nd er d ow n-sh if te dc o n d i t i o n s .

d. The pr ima ry r e g u l a t o r i n l e g I w a s control l ing under down-s h i f t e d r e g u l a t i o n . The p ri mary r e g u l a t o r i n l e g I1 a l s o s t a r t e d t osupply flow because of t h e c h a r a c t e r i s t ic s of t h e two r e g u l a t o r sreach ing t h e same con t ro l p r essu re . Tes t s have shown t h a t undert h e s e c o n d i t i o n s , a r i s e i n r e g u l a t e d p r e s s u re c an b e e x p e c t e d .Any o f t h e s e c o n s i d e ra t i o n s p o i n t o u t a f a i l u r e i n t h e p ri ma ry r eg u-

l a t o r o f l e g I t o ma i n t ai n e x pe c te d r e g u l a t i o n p r e s s u re s . I t e m 4b c a n b er u l e d ou t i f two f a i l u r e s of d i f f e r e n t t yp e s i n ea ch o f t h e p r ima ry r e g u-l a t o r s c an b e ig n o re d.

The aspects of items 1 hrough 4 i s o l a t e t h e p ro blem t o t h e p ri ma ryr e g u la t o r i n l e g I , c h a ra c t e r i z e d by a down-shift i n re gu la t i on which mayor may n o t have p a r t i a l l y c o r r e c t e d d ur i n g t h e f i r i n g .S e v e r a l p o s s i b l e f a i l u r e s w i t h i n t h e r e g u l a t o r c o u l d h av e c a u se d a

down-shift .t u a l e f f e c t on t h e r e g u l a t i o n p r e s s u re . T he se r e s u l t s a r e e x p e c te d byA p r i l 1 9 . The p re s e n t l y i d e n t i f i e d t y p e s o f f a i l u r e which c an c au s e ad ow n-sh if t i n r e g u l a t i o n a r e n o t d e t r im e n t a l t o t h e o p e r a t i on of t h e as-cen t propuls ion system. Consequent ly , no hardware changes a re an t ic ip a t edf o r A p o ll o 10 .

These w l l be s imu la te d on a r e g u l a t o r t o d e t er m in e t h e ac-


ROUGH DESCENT ENGINE THROTTLING

D ur in g t h e s ec o nd d e s ce n t e n g in e f i r i n g , t h e e n g i ne w a s rough a tabout 2 7 p er ce nt t h r o t t l e f o r a few seconds, t h e n s e t t l e d o u t a nd o p er a t e dsmoo th iy du r ing th e remainde r of t h e f i r i n g . The da t a du r ing th e roughperiod showed a r i s e i n t h e o x i d iz e r i n t e r f a c e p r e ss u r e , fo l lowed by ar i s e i n t h e f u e l i n t e r f a c e p r e s s ur e , an d b ot h s ub se qu en tl y r e tu r n i n g t oth e normal p ressu re . Dur ing t h i s t ime pe r iod , t h e eng ine chamber p res -s u re f l u c t u a t e d , c a u s i ng t h e roughness .

T e s t s have shown t h a t w i th h e l i um d e l i b e r a t e l y i n t ro d u c e d i n t o t h el i n e , t h e i n t e r f a c e p r es s ur e s i n c r e a s e as t h e gas p as se s t h e t h r o t t l e


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ass embly . The t h r o t t l e d a r ea ope r a te s at c a v i t a t i n g p r e s s u r e s , g i v i n gr i s e t o a pr es s u r e i nc r eas e as t h e he li um pas s e s t h r ough t h e a r ea .v a r i a t i o n o f i n t e r f a c e p r e s su r e s and t h e b l e e d in g o f h e li um i n t o t h e i n -j e c t o r r e s u l t i n f l u c tu a t i on i n the engine chamber pre s sur e . These t e s tr e s u l t s match ve r y c l o s e l y t h e f l i gh t da t a dur in g the engine roughness .

The

The he l ium i n t h e p r ope l l an t t anks c ou ld e n t e r t h e p r o p e ll a n t l i n e sunder ce r t a i n condi t ions of acce le ra t i on . However, a zero-g cup ove rt h e l i n e s i n s i d e t h e p r o p e l la n t t an k g r e a t l y r ed uc es t h e l i k e l i h o o d o fh el iu m g e t t i n g i n t o t h e f e e d l i n e s .

I n any even t , t e s t s have demonst ra ted t h a t i nge s t i o n o f he li um i n t ot h e engine i n t h i s manner has no detr ime ntal e f f e c t on t h e system. How-eve r , i f h el iu m s h ou l d g e t i n t o t h e l i n e , t h e e n g in e may f i r e roughlysometime dur ing th e f i r s t s ev era l seconds of a f i r i n g .


G O V E R N M E N T - F U R N I S H E D E Q U I P M E N T

A I R BUBBLES I N LIQUID COOLED G A R M E N T

A f t e r t h e Lunar Module P i l o t removed h is l i q u id cooled garment onext rav ehi cu la r ac t i v i ty day , he no ted many a i r b ub bl es e n t r a i n e d i n t h el i q u i d t u be s .

The p r e f l i g h t c h ar gi n g p ro ce du re f o r t h e p o r t a b l e l i f e s u p p or t s ys -tem has been reexamined fo r the p os s i b i l i ty o f a i r i n cl u si o n i n t o t h es ys tem dur i ng cha r g ing , and t he po s s i b i l i t y w a s e l imin a ted . The a i r mostp r obab l y en t e r ed t h e s y s tem du r ing connec ti on o f t h e po r t ab l e l i f e sup-p o r t s ys tem t o t h e l i qu i d cool ed garment i n t h e p r e s s u r i zed l una r modulecab i n . B ecause o f t h e l oc a t i o n of t h e coolan t make-up l i n e f o r th e por -t a b l e l i f e s u pp or t s yst em , when th e t o t a l p r e ss u r e i n t h e l i q u i d c oo le dgarment i s l e s s t h a n t h a t i n t h e p o rt a bl e l i f e s up po rt s yst em , a i r i si nges t e d th r ough t h e s ub l ima t or i n t o t h e coo l an t l oop . A design changet o t h e p o r t ab l e l i f e s up po rt system t o e l i m i na t e t h i s problem i s i n p ro -cess and w i l l be a va i l ab l e f o r t he Apol lo 11 har dw ar e ( s e e f i g . 2 2 ) . Thischange w i l l r e l o ca t e t he make-up l i n e t o t h e ups tr eam s i de o f t h e w a te rs h u t o f f a nd r e l i e f v a l ve .w a t e r i n s t e ad o f ga s .

Any pressure make-up w i l l be r ep l en i s hed w i t h



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Y

STOWAGE OF O X Y G E N PURGE SYSTEM PALLET

The crew could no t in se r t t h e lock ing p i n th rough t h e lun ar moduleb ul kh ea d s t r u c t u r e i n t o t h e oxygen purge sys tem p a l l e t when res towing t h epu rge sys tem and pa l l e t . The l oca t i on o f t h e ho l e i n t h e bu l khead b r acke t ,a d ja c e nt s t r u c t u r e , l i g h t i n g , an d a n gl e of i n s e r t i o n c a us ed d i f f i c u l t y i na l i g n i n g and i n s e r t i n g t h e p i n .t h i s k in d o f p a l l e t w i l l he u sed and t h e only miss ion on which t h e oxygenpurge sys tem w i l l b e sto we d i n t h i s l o c a t i o n .used on LM-4 and LM-5 t o h o l d t h e p o r t ab l e l i f e s up p or t s ys te m by t h e r e-char ge s t a t i o n , where t h e l i gh t i ng and a li gnmen t access a r e good.

This miss ion w a s t h e only one on whichThe same t y p e p i n w i l l be


LI GHTI NG FOR CREWMXV OPTICAL ALIGNICENT SIGHTC r e w comments ind ic at ed th a t dur in g docking a t 99 h o u r s, t h e b r i g h t -

nes s of t h e background and t h e s u n l i t command module washed out'' t h er e t i c l e image i n t h e l una r module crewman op t i ca l a l i gnment s i g h t . T h i sproblem w a s caused by t h e n e u t r a l d e n s i t y f i l t e r , which w a s h ou se d i n t h eb a r r e l assembly t o l i m i t b r i gh t n e ss o f t h e r e t i c l e p a t t e r n . T hi s f i l t e rw i l l be rep laced wi th a d i f f u s e r g l a s s , and an external snap-on f i l t e rw i l l be provided f or a t t achment over t h e forward end of t h e b a r r e l . Witht h e f i l t e r removed, t h e b ri g h t n es s o f t h e r e t i c l e p a t t e r n i s i nc re as ed t oa l lo w t h e r e t i c l e image t o b e v i s i b l e a g a i n st a 10 000 t o 1 6 000 f oo t -lamb ert gl ar e background. This change w i l l be implemented on Apollo 1 0 .


OXYGEN PURGE SYSTEM LIGHTThe checkout l i g h t on t h e Commander's oxygen purge sys tem became

e r r a t i c d u ri ng t h e f l i g h t a nd f a i l e d t o come on d u r i n g p r e p a r a t i o n s f o rrendezvous. An examination of a l l pos s ib l e condi t ions which could havec au se d t h e checkout l i g h t t o f a i l i nd i ca t e s t h a t t h e main power s w i t chac tua to r mechanism d i d no t c lo se t h e switch . Changes incorp ora ted in tothe actuator mechanism or Apollo 10 and subsequent a r e :

1. Change type of Tef lon inser t mate r i a l i n t h e f l e x i b l e c a ble2 . Change t o a s wi ve l j o i n t i n t h e f l e x i b l e c ab le a t t h e oxygenpurge system in te r fac e


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4

19

3. Increase cam r i s e on switch actuator cam4 . Bond switch actuator cam t o s l i d e5 . Bond s w i t c h i n p l a c e a f t e r a dj u s t m e n t.This anomaly i s c losed .


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Apollo 9 30 Day Failure and Anomaly Listing Report

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Transcript of Apollo 9 30 Day Failure and Anomaly Listing Report