VZI-B

¶To: WArro~iatoAdministrator for Spaco ?light now: 1QS/Irr Davidr SUUECT: Car. to Car. and Worrlo to Car0 "0" ling Soa1 Erorlon

¶?roblomr

¶As a rorult o f tho problomr balni Incurrod durlng f3ight on both CI S . to car0 ond noxxlo to oaro 0" rial oroilon. nr. Hamb and I riritod X I l C on July 11, 1011, to discuss this Irruo with L t h projoct and SID porronnol. lollowing oro romo important factors concoralae thoro problom: A. IIorr10 to C8ro aF?In# ororlom T h o luvo boom twolro (12) Inrtrncor darine flight whoro thoro haw boon SOW prlury "0" rIn8 ororlon. In o n. rpociflc cmo thoro war also ororios of tho rocondary "0" ria# 8 0

.1 . thoro

¶woro tw (2) priur "0" sIa8 roalr that n r o hoat rffoctod (no ororion) u d t w o (a! casos In which root blow by tho priury moa1r. Tho p r i w rurpoct as tho CIUSO for tho ororion on tho primary "0" ring roalr Is tho typo of putty urod. It lr lhiokol*r position thot during arrembly. loak chock. or Ignltloa. Lolo Can k formod throu h tho utty whlch Inltirtor "0" ring ororlon duo t o jotting offoct. it is Important to noto that aftor STS-10. tho unufacturor of tho putty wont out of borinorr and now putty sanufocturot wor coatrrctod. n o BOW potty is bollorod to k IOFI rurcoptiblo to onrironmontal offoctr such as molrturo whlch u k o r tha putty m o m tacky. n o r 0 aro rarlour options bring coarldorod rucb as romoval of putty. roryln tho putty conflguratlon to rowat tho j otti.8 offoct. IJSO of putty amdo by a Canadian &aaufrcturor which Imcludor arbortor, and vrriour combisatton of putty ond grraro. n o r m 1 analysis andlor torts at. andorway to ~ r r o r rthoso optlrr. Thlokol 1s rorlorrly c o n ~ i d ~ r i rtho dolotIom of utt om tho PC- S roaalo/caro jolrt rlrco thoy folIaro tho utty 1s tio pTIW * caaro o f tho ororion. A docIrIoa om t h i s cKanSo t o planad to k n u d o t h i s wok. I h o w rmrorratlonr about dola# It coaridorina c ot l 91-r t k r ~ g n ~ f ~ c a mof ~ iirtma tm quolityina t L me tor fllgbt.

377

¶It is 1 . ortrnt to mot0 thot tho cruso rnd offoct o f tho putt rrrlor. fboro rro romo WFC orromol rho aro sot convincod tirt tbo bolo# in tho putty rro t!o rourco o f tho problom but fool that i t may bo 8 rovar$o offoct in that tbo hot grror u bo lorking through tho roal and causing tho bolo track la tgo putty. Conrldoring tho fact that thrro doorn't appoar to bo 8 rrlidatad rorolutlon 8 r to tar offoct of putty, I would cortrlnly euerrlen tlr r l & w i a tmmarrng 1% on ipt-5.

¶Thrro h a w boon f f v o ( I ) oc~urroncosduring flight whoro thors ras primary f i o l d joint "0" ring ororion. Thcro vas one car. whore tho rocondar "0" rln ras hoar affoctod rith no ororion. Tho ororion vlth tn, field folnt primary "0" rlngr is conrldorod b romo t o - b o moro critical than tho norrlo joint duo t o tho fact tgot during tho prorruro build up on tho p r i u r y "0" rin tho unprorrurirod fiold joint rocondrry rorl unroatr &a0 to f o h t rot t ion. Tho problom rlth tho unroating of tho rocondary "0" ring durlag joint rotation ha8 botn known for uito norno t h o . In ordor t o ollmlnatr thir roblom on tho FXC !iold joints capturo foaturo vas drslgnod u h

¶!ch provontr tho ~ocondriyrorl from lifting off. Durin our dircurrlonr on this isrua rith MSFC, 8n rctlon war arsigno! for tho8 to idontlfy tho timing rrrociatod with tho unseatlag of tho rocondary '*O" ring and tho m 4 t i n # of tbo primary "0" rln durin rotation. How long it t a k a tho recondary "0" rfng to fift off during rotatlon and rbon in tho rerruro cyclo it lifts mro koy frctorr in tho dotor8inrtion of P t r criticality.

¶Is Tho proront C O ~ ~ O I I S U~that if tho rimmry "0" ria roatr durln ignltion, 8nd rubroquontly fri!r, tho unroatod rocondrry ''0" rfng will not rorvo Its intrndod purporo as r rodundont seal. Hovovor, rodundrnc door oxlrt during tbo Ignition cyclo, bhich tho most cri?icaI t h o . * t 1s rocommondod thrt ro rrrrn#o for WSFC t o provido an ovorrll brl0fing to you on tho SRll "0" rings, including friluro hlrtoty, currant status, and options for corrocting tho problo~r.

¶6 4 - 4 2 0 0 - 86 - 1 3

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¶STS-51L (STS-33 )

¶SOLID ROCKET flOTOR (SRH-251, .., . ,

¶FLIGIIT READIt!ESS ,REVIEH

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.. , * .' .. . , . . . . *. .. . . . . .⁸⁸ Ibid. Ibid. ' 0 bid. I 1bid. Morton Thiokol, "Program Plan, Protection of Space Shuttle SRM Primary Seals," TWR- 14359,May 4, 1984. Discussions with Allan McDonald and Carver Kennedy, Thiokol (Wasatch Operations), Brigham City, Utah,, September 4, 1986. . . . . . . .. .. .. . . . . . " , . '. .. .. iI . . . . .. ... . . . .. ... w ,i .. .... .. .. . . .. . . . 00 . ... . . . l b ; . . .. . . .. -. . . . . . . . . .. . . . . . .. .. . . .. . . . . . . . .. .

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¶.. . . 11"DECE)IBER1985 . . I

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'. . L I ....⁴⁴ Rogers Commission Report, Volume 1 1, p. H-1. . . . . I :

WASATCII D I V I S I O N

' P.O. BOX 524'; RRIGIIAll C I T Y . ~ l ~ T A H 8 9 3 0 2 .(801) ,863-3531,

.o S I S - 6 l C (SIS-32) ( SRtl-24) PERFORMIICE

7.0 0 PROBLEM SUEIMARY

¶I

¶3.0 0 S T S - 5 1 1 (STS-33) (SRM-25) CllANGES

0 CllANGE SVIMARY

¶0 DESIGtI

0 . IIARDWARE CHANCIEOUT

0 PROCESS CllAN6ES 0 F IRST 1I tE CONF I GIIItAT I ON REUSED

0 OMRSD

¶0 OHD

¶CERT IF ICAT ION/VER IF !CAT lot1 STATUS

¶STS-511 ISIS-33) (SRH-25) PERFORflAllCE PREDJ CT I OMS

lECllNICAL ISSllES I 0 F L 1 6 t l T REAUltlESS REVIEW ,

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387

¶VnI-c

.Organizational Issuance 81- em -I(

Dccetzber 2 9 , 1383 SOP 1000.1 4.9u.L. Shuttle Prciecrr Office

¶&bi.rr SHUTTLE PROJECT FLIGHT READINESS R E V h P

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