Development of LOX-Hydrogen Engines for the Saturn Apollo Launch Vehicles

8/4/2019 Development of LOX-Hydrogen Engines for the Saturn Apollo Launch Vehicles

http://slidepdf.com/reader/full/development-of-lox-hydrogen-engines-for-the-saturn-apollo-launch-vehicles 1/13

E N G I NE P R O G R A M O F F I C E

SATURN HISTORY DOCUMENT

U n i v e r s i t y of Alebema Research I n s t i t u t e

Hiet~ry f:Science G. T e c h n o l o g y Groilp

Date ---------- Doc. No.----,,,

DEVELOPMENT OF LOX-YY DRO GEN EN GI NES FOR

THE SATU R N A P O LLO LA UNCH V E HICLE S

NA TIO NA L AERONAUTICS AND SPACE ADMINISTRATION



DEVEL OPME NT O F LOX-HYDROGEN ENGINES FOR

TH E SATURN APOLLO LAUNCH VEHICLES

A. J. 'Burks, As sis tant Manager

Engine Pro gr am Off ice

Nat ional Aeronaut ics & Space Adminis t ra t ion

Mars h a l l Sp ace F l ig h t C en te r , A labama 35812

Ab s t r ac t

Durin g the development of the RL-10 and 5-2

engines , many problems wer e encountered . Sol-

u t ions to the s ign if ican t problem s a r e conta ined .

A des crip tion of these LOX-Hydrogen engines.

outlining the unique featur es of each w i l l be given.

Pe r fo rm an ce p a r am e te r s f o r bo th en gin e s y s t em s

a r e t abu la ted . Specific applications to various

s t ag es a r e s ho wn . S ta r t an d r e s t a r t co n di tion s a t

a l t i tude a r e a very im por tan t ad junct to the engine

development and a r e presented in the paper . T e s t -

ing an enqine des igned to opera te a t a l t i tude a t

ambient se a level condit ions presented som e in te r -

es t ing problems and requi red pecul iar t es t equip-

ment. Th e so lu t ion to the.se prob lems and a des -

criptio n of the tes t equipment will be covered.

Fl igh t data revealed some anomal ies tha t wer e

la t e r v e r i f i ed a t t h e a l t i tu d e t e s t f aci l it y a t Arn o ld

Engineer ing Development Cente r , Tul lahoma,

Tennessee . A description of the anomalies and

ver i f ica t ion tes t ing wi l l be made.

Introduction

The nat ure of propuls ion sys tem development

is such that i t becomes the pacing i te m in a new

vehic le program. Th is h as b een t r u e in a i r c r a f t

a s w e l l a s m i s s i l e p r o g ra m s . Th e ex ten s iv e t e s t -

ing, design , redesign, and re te st have shourn that

p ro p u ls io n s y s t ems g en e ra l ly mu s t l ead b y s e v e ra l

ye ars in the development cycle . Th i s n eces s i t a t e s

the initiatio n of an engine development pro gra mpr i or to the deta i l des ign of the vehic le . This pre-

\ sen ts the obvious problems of in ter f ace , power

requ irem ent def in i tion, contro l sys t em re la t ion-

sh ips , e tc . . which m us t be again evaluated a s the

vehicl_e design i s f inalized. Engine redes ign o r

co mp ro mis es u s u a l ly r e s u l t f r o m th es e i t e r a t ion s .

Once the technical need has been es tab l ished

fo r the developinent of a new propulsion sy st em

and the economics of the sys tem have been evalu-. ated, then tge design trade-offs begin. Vehicle. -

rcquire l l len ts wl~ic hnclude such bas ic fac tors a s

staging, payload u~eigh t,mission f lexibili ty? and'

reliabili ty must be fed Sack into the basic engine

:design

asthe sy s tem evolves . Wherever poss ib le ,engines a r e des igned to be u t i l ized in m ore than

on e stage . Following this philosophy the RL-10

engine found us e on two different ve hicles and

the J-2 engine is u t i l ized on three s ta ges of two

vehicles . .

Thi s :'common engine" approach allows the

contrac tor to concentra te on one des ign, ' re su l t s

in higher re liabili ty due to repeti t ive tes ting of a

single configuration, and reduce s production cost s

s ince the engines can be bought in lar ge r quant i -

t ies . A common engine configuration also s impli-

f ies the spa re par ts and f ie ld suppor t requirem ents .

and pe rm its interchangeabili ty of basic components .

Thus new engine development program s a r e

optimized by a me ld of the practical u se of the be st

technology availa ble within the cohstra ints involved

and a vigorous trade-off of the perform ance pa ra m-

ete rs . The choice of expansion ratio, for example,

was one not only of perfo rmanc e, but of the eco -

nomics involved in building the tes t facili t ies re-

quired for engine development. The RL-10, being

a sm all er engine,. could us e a higher expansion

rati o (and thus take advantage of the higher s pecif ic

impulse) because i t was pract ica l to bui ld s tea m

ejecto rs and d i f fusers for engines in th is s iz e range.

Such a choice for th e J-2 engine would have been

prohib itive f ro m the stancipoint of co st due to the

siz e of the facili t i es involved. Hence, one of the

r eas o n s a 27. 5/1 expansion ratio, was chosen f or the !5-2 engine was to accommodate tes t ing a t sea level

conditions.

The guiding philosophy of the N ASA-M arshall

Space Flight Ce nter in developing engines is to

schedule a detailed component tes t fol-lo-ved by an in-depth engine tes t p ro gram to f er r e t

out as many la ten t hardware defects a s poss ib le

before f l ight tes ting. A vigorous production sup-

por t p rog ram i s main ta ined concurrent wi th the

development phase and H e improvenlen ts a r e

incorporated into the embryonic design as soon as

pract ioal . This p lan has worked success fu l ly bc-

ca us e it continues to challenge the best technical

minds to reach out "over the horizon" fo r bette r

idea s which have resulte d in continual payload

in cre as es for NASA's launch vehicles . This pro-

duction support effort has been the backbone fo r

reso lving the problems resu l ting f rom engine- s tage

integra tion and testing. This process continues

as long a s vehic les us ing the engines a re f lying .The feed back of production and flight pro ble ms into

the engine programs is an essen t ia l e lement in .der iv ing a re l iab le sys tem , and a lso serv es the co-

function of allowing the engine design, tes ting , and

manufacturing proced ures to catch up with the s tat e

of the art .



9 P a r t I: Developm ent of the RL-10 En gine

T he A po l lo P r o gr a m w a s c onc e ive d w i th t he

idea tha t a des ign evolut ion would be re qui red be-

f o r e t he l a r ge ve h i c le su i t a b l e f o r ma nne d luna r

landing could become a r e a l i t y . The planned evo-

lu t ion w a s f r om the S a tu r n I to the Sa turn IB, and

finally to the Saturn V . Since the l iquid oxygen

(LOX)- l iquid hydrogen (LH2) RL-10 engine was a l -

r e a dy io de ve lopme nt on the Ce n t a u r p r o gr a m

when the Sa turn 1p r o g r a m w a s s t a r t e d , a n up -

r a t e d ve r s ion ( LR- 11T ) w a s c hose n f o r t he h igh

pe r f o r ma n c e uppe r s t a ge p r opu l s ion . T he op t i-mi s t i c de ve lopme nt p r o gr a m f o r t he L R- 119 i a i l e d

to mate r ia l ize and coupled wit!, ma jor d i f f icul t ies

in t he RL - 10 de ve lopme nt p r o gr a m r e su l t e d i n a

p r og r a m r e d i r e c t i on . A c ommo n ve r s ion of t he

RL-1 0 engine was def ined to meet the requ i re -

me nt s of both the Cen taur and Sa turn I p r o g r a m s

a nd ~ l l o w e dhe c on t r a c to r t o c onc e n t r a t e on one

d e v e l o p m e n t p r o g r a m .- . .

A n a l l cr yoge n i c p r ope l l a n t s ys t e m of l i qu id

hydrogen and l iquid oxygen was chosen bec ause of

the high spec i f ic im puls e a t ta in able . ~ a j A r r e a k-

throughs in l iquid hydrogen technology mad e both

pr ope l l a n t s r e a d i l y a va i l a b l e a nd r e l a t i ve ly i ne x-

pe ns ive . In a dd it i on t he se p r ope l l a n t s a r e non-toxic and give s t ab le combus t ion.

The R L - 10 e ng ine w a s suc c e s s f u l l y use d on

the S ur ve yor P r o gr a m in a n A t l a s - Ce n ta u r ve h i c l e

(Fi gur e 1) to boos t the payload to a lu nar landing.

I t w a s a l s o used in the Sa turn I ve h ic l e ( F igu r e 2 ) ,

t o p l a c e t h r e e P e g a sus m e te o r o id t e chno logy sa t -

e l l i t e s i n to o r b i t .

F i g u r e 1. A tl as C en ta ur E ng in el sta ge ~ ~ ~ l i c a t i o n

In the Sa turn 1 p r o g r a m t h e R L - 1D engine be-

c a m e a n _excellent t e s t -be d f o r A po llo ha r dw a r e

de ve lopme nt . The S-IV stage-of the Saturn I w as

a fore run ner of the S- IVB s tage in the Sa tu rn IB

a nd V ve h i c l e s . L ike w i se , e xpe r i e nc e gaine d i n

deve loping the S- IV and Cen taur s tag es was ut i -

l ized in des igning the Sa turn V S-I1 s tage .

9

F i g u r e 2 . Sa turn I Engine is -1V Stag e Appl ica t ion

Descr ipt ion

-Th e RL-10 engine ut i l izes a r e ge ne r a t i ve ly

cooled thrus t chamber and a turbopu.mp-fed propel-

lant flow sy s tem . Due to i t s high hea t capac i ty ,

the l iquid hydrogen ve ry effectivcly cools the thru st

cham ber . While pass ing through the thru s t cham-

be r tub es , the hydrogen picks up hea t and i s ex-

panded in a two-s tage turbine to dr i ve a s ingle

ge a r c d t u rbopump. The fuel is then injected into

the c ombus ti on c ha m be r . This "topping" cycleprov ides a per fo rman ce ga in of approximate ly 112

- - .to 1 perce nt over that of a conventiona l gas ge ner a-

tor type cyc le . Oxidizer i s pumped di rec t ly to the

prop e l lan t in jec tor through the mixture ra t i o con-

t rol va lve . Thrust . con trol is achicv ed by regu -

lat ing the amount of fuel bypassed arou nd the tu r-

bine a s a func tion of combust ion chamber p re ss ur e

in order to vary turbopump speed and thereby con-

t rol engine thrus t . Ignit ion i s accompl ish ed by

me a ns o f a n e l e c t r i c spa r k - to r c h i gn i t e r r e c e s s e d

in the prope l lant in jec tor face . S ta r t in g and s top-

ping a re cont rol led by pneumat ic va lves which re -

ce ive th e i r supply of he l ium through e le c t r ica l l y

opera ted va lves . Major pa ram et er s of the R L - 10

e ng ine a r e de p ic t ed i n F ig ur e 3 .

F i g u r e 3 . RL - 10 E ng ine Ma jo r P a r a mc tc r s



, A functional description of the engine is shown

i n Fiy r e 4.

F i g u r e 4. RL-10 Enginc

Developxnent Pr og ra mFig ure 5 shows the~deve lopm'enf yc le for the

RL -1 0 engin e v..llich f all s within the typi cal 5-7

ye a r spa n re qu i re d fo r p ropu ls ion sys te ms .

Tes t ing under s imula ted Centaur s ta ge condi-

t ions on a dua l-pos it ion ver t i ca l tes t s tand contr i -

buted significantly to the lack of engine pro ble ms

once vehicle ground and flight testing commenced.

Vehicle components such as the hydraulic po wer

pack, propellant utilization drive moto r, r e c i r c u l -

ation ducts and diffuse rs, vehicle boost pumps,

and re tromaneuver discharge duc ts were tes ted

on the dual-engine stand under conditions closely

approximating those found on the actua l s tage in

flight. Thi s not only allowed inter action s on th eengines to be identified, but permitted accurate

simulation data for purpo ses of developing the sta ge

components.

Produc t ion support e f for t was ini t ia ted to min-

imi ze the impact of production probl ems and con -

t inua l ly impro ve s ys tem re l iabi l i ty and f l ight .wort hiness . This included establishment of vehi-

c le s ta r t ing sequences and l imits , opt imizat ion

of prelaun ch chilldown and boost pump sett ing s,

and investigation of flight problems.

Basic technology was developed in speci al te st

fac i l i t ies , hydrogen injec tors , ignit idn sys t ems ,

idling and throttling, reduced net positive suction

head (NPSH) operation, the use of cryogen ics for

a bearing and ge ar coolant and the feasibility for

a "zero chilldo\vn time" engine.

The RL-10 has not only been a reliab le engine

sys tem for the Sa turn and Centaur program s, but

has se r ved as a " tes t-bed" for other a reas of

technology. The use of fluorine a s a11,oxidizer was

pro ven on modi fied engin es of an ea;G_vintage to

provide one of the f i rs t " fl ight we i~ ht " luor ine- -prototjrpe engines. This w as arcolnplislled by mod-.

ifying the pump seals in the oxidizer system to pro-

vide fluorine compatibility and by changing the

engine "trim".

A modified RL-10 engine has run successf ully

in the throttling mode down to one percent of the

ra ted engine thrus t . The feed sys tem was s table

a t a l l thrus t leve ls in this range . F u r t h e r , a

modified RL-10 has operated in the low-idle mode,

in which the turbopump does not r otate b ut the. . . . .

2; ..--- ---& engine ope ra te s on tank pre ssur e with gaseous ,cCall U a j . E ~ liquid. o r mixed-phase

Other areas. , such as hypergolic ignition through

the use of a small perc entage of trioxygen difluoride

in the oxidizer and ins tant-s ta r t or ze ro cooldownF i g u r e 5. RL-10 Projec t Miles tones tim e accomplished by insulating the fuel pump in -

te rna l surfaces , were inves t igated us ing the RL-10The f i rs t Centau r f l ight ut i l izing an RL-10 engine as a l~ te s t -bc d~ lnd were pro,7en feasible.oc cur red fix-e ye ar s a f te r pro gram init iat ion. Ap- r:

proxilna te ly $240 mil l ion do l la rs was spent on the , Problems

RL-10 engine program of whicll about seventyThe RL - 10 engine encountered-a wide galnut of

pe rc ent \-:as sp en t on the developnlent phase. probl ems during development. Some of the majo r

.. pro6lem a re as a re l is ted below. .'

T he e ng ine , in i t s va r ious v e r s ions ha s c om- (1 thrus t over shootpleted 01 e r o ne nill lion seconds of total firin gs; ( 2 ) gimbal block lubrication -and has been flown on 15 Centaur flights and six - ( 3 ) spark igniter deficiencySaturn f l rghts. A total of 66 engines have been -

flo\i.n with n o malfunction which affected the m is -

sion. b

3 ;



. Th rus t Overshoot. The Cent aur vehicle wa s Gimbal Block Lubrication. The gimbal ass em -

unable to accept m or e than 15 perc ent th r us t over - bly is the componen.t with the highest unit loading

shoot. Th rus t exceeding the specif ied l imi t oc-

cu r r e d b ecau s e th e en gin e th ru s t co nt ro l v a lv e

( F i g u r e 6) was s e t t o ma in ta in a ch amb er p r e s s u re

of 300 ps i and d id not by-pass any turb ine dr iv e

g as u n ti l t h e n o min a l th ru s t l ev e l was reached.

T h e s y s t e m m o m en t um w a s n o t r e t a r d e d e a r l y

enough to prev ent the overshoot . Adjus tments ins p r i n g p r e s s u re o n the th ru s t co n t ro l p i s ton p r e -

vented exces s ive th rus t overshoot , bu t caused the

sys tem to s tab i l ize below the nominal th rus t level .

The problem w as so l ved by the incorpora t ion

of a "pneumat ic r ese t" on the th rus t contro l . Th e

th ru s t co n t ro l b y -p a ss w a s s e t t o op en a t a l o we r

ch amb er p r e s s u r e ( ap p ro xima tely 270 ps i) , and the

d es i r ed n o mina l 3 00 p s i ch amb er p r e s s u re was r e -

es tab l is hed by use of the pneumat ic re se t sys tem.

' The referen ce pr es su re on the back s ide of the

th ru s t co n t ro l b y -p as s p i sto n i s a tmo s p h e r i c p r e s -

s u r e wh ich i s e s s en t i a l ly ze ro p s i a t t he en g in e

opera t ing a l t itude . When the thrus t contro l ler by-

p as s i s ac tu a ted a t th e lo wer ch amb er p r e s s u re

leve l, hydrogen is vented into the thru st control

body. By orif icing the thrus t cont rol valve body

vent , the body pr es su re and p is ton ref eren ce pres -

s u r e a r e in c r eas ed ap p ro x ima te ly 3 0 p s i which r e -

s e t s the by-pass re l ief p re ss ur e to ob ta in the nom-- -

* - , . ,i n a l 300 p s i ch amb er p r e s s u r e . ,By this method

the r ' ese i p ressure lags the body dur'ing

engine accele ratio n \vhich allows the thrust contro l

valvd to reLurn to a nominal pos ition before thc de-

s i r ed 3 00 p s i ch a tn b e r p r e s s u r e i s r each ed .

Development of a backup elec tro3i c thru st con-

t ro l le r was in i t ia ted in the product ioh s uppor t p ro-

gr am and the des ign had prog ress ed to the po int

whe re a de cis ion could have been made to use i t

when the modified pneuma tic con trol ler proved

s , a t i s f a c t o r y ..h * - - - =7

i.~ & u r c 6 . Th rus t Contro l Valve Schemat ic,z.%, *. -

aid is the only loaded compo nent that i s exposed to

high vacuum during engine operation. Space vac-

uum effect on mat eria ls is s ignificant in two

r e ~ ~ e c t s .

(1 ) evaporat ion of solid s

(2) vaporization of surf ace gas lay ers

1Evaporation of mat eria l is not a significknt pro-

blem because of t1le rate of m ater ial los s i s negli-

gible at te mpe ratu res below 300°F and the engine

surface temperatures remain continuously below .this crit ical range. Vaporization of surf ace gas .lay ers of engine components is a s ignificant pro-

bl em beca use of the assoc iate d phenomenon of "cold

welding. " Degass ing a meta l sur face removes the

oxide coat ing that i s characte r is t ica l ly presen t

within the atmos pher e of the earth and pro te cts the

me ta l s u r f ace ag a ins t ~n o lec u la r t t r ac t io n of s imi -

la r c lean mater ia ls . Also the f r ic t ion behveen the

rubbing metals increases proportionately to the ex-

ten t tha t the sur fa ces a re degassed . A d ry f i lm

lubr ican t (molybdenum disulphide) was developed

fo r the gimbal block to reduce the increas ed torque

encounte red under sp ace conditions to a tolerable

leve l well within the s t ruct ural capabili ty of the

engine and the vehicle.

Spa rk Igniter Deficiency. The f i r s t s t a t i c t e s t

s tan ds ' t hat were buiIi for the R L - 10 development

pro gra m positioned the engines in a horizontal att i-

tude for firing into a long diffuser. The d i f fusers

wer e used to cre ate a vacuum around the engine

pr i or to s tar t . Late r a dual engine tes t s tand was

'built in.wh?eh.the engines w er e positioned verti-

cally and f ired downward into diffusers fr om a n

elevated facili ty. The f i r s t a t tempt to f i re an

RL-10 engine vertical ly resulte d in an explosion

that extens ively d lmaged the engine and tes t facil-

itie s. .The ensuing investigation prov ed that LO X

was introduced intd the thrus t chamb er in suc h a

way that i t bypassed the igniter. During the s t ar tof a horizontal engine fir ing , the LOX fo rmed a

pool inside the thru st chamb er. Boil-off f rom this

pool mixed with the hydrogen to fo rm a com bus -

tible mix tur e fo r ignition. When the engine wafi

f ire d verticall y, the LO X droppsd to-the bottom of. L -

the diffuser tubes, and the ignition occ urr ed at that

point. The explosion pro gre ss ed up through the

diff user s to the engines and test facili ty. The cn-

gine inje ctor was modified s o that both oxygen and

fuel wer e rou ted pas t a rece ssed spa rk- torch ign i-

ter dur ing s t ar t and so lved the problem.

Up ra ti'ng

There has been a sus ta ined spectacular payloadincr ease over thc years att r ibuted to engine im-

provement . A s s h o v ~ n d F i g u r e 7, an increase of

a l m o s t 800 ' Ibs.of payload has re sult ed from engine

improvements made over a s ix ycar period: Es s en -

t ia l ly a l l of these amel iora t ion s resu l ted f rom i tn-

pro vem en ts i:l efficienc y with the IS P progressing



* - s te p -wise f ro m the o r ig ina l de s ign spe c i f ic a - Design f lexibi l i ty had to be mainta ined s i nce

t ion l im i t of 412 lb. s e c i lb to a deliwered the J -2 engine was to be used in the second s tage

no ~ni na l f 442 lb s e c l lb . of the Sa tu rn IB a nd the s e cond a nd th i rd s ta ge s

of the Saturn '7 , a s shown in F igure s 8 and 9.

----RLIOA-I SPEC YL\ rSP. i 12 SEE . EL OX< SSP

F i g u r e 7. RL-10 Engine Contr ibut ion to Centaur

P a y l o a d I n c r e a s e

F i g u r e 8. Satu rn IB-V, Engineis-IVB StageAc c ompl i shme nts

Application. Som e of the accompli shments of the RL-10

e n gi n e p r o g r a m a r e l i s t e d b e lo w:(1 ) First LH2/LOX engine

r- --- --- -- -- --- - I- -2.. -- - .".(2) Develope d LH2 techfiology -- -- - - '1- -(3 ) Combustion Stabi l i t y ! I; F I V E 1- 2 IhCINfS OH 5-11 STLCL

PROPELLAW1(4 ) Mult ip le s ta r t c a pa b i l i ty -

1 .' F i LOI/LH2/ , 0111 l"R"l,(5 ) Idl ing and throt t l ing capabil i ty ! .--%&/...-

1I

~. lzs.ooo 0;I

(6 ) Test-bed for oth er a re as of technology i- 1 : 1.!50.OGO LB

" 3 - 3 , ,- ": ',

LAa gL<_;' . . . .< gg - - -,

T h e RL -10 e ng ine ha s be c ome a work-h orse in9-

the pr .op1s ion f ield . In addit ion to b e i n g a n e x - + I : -. - . l-. - 5 " - ,I- -c e l le n t experimental tool it a l so wa s the fo re -

/. 5 - <.,{'

;7 * :;,-5 . <>run ner of the J -2 and M -1 engines. ' \ ,

, \.-I

- 'Iy-.

I ;..-r, --..- % -l, .. .rP a r t 11: Development of the J-2 Engine ,? . -

*. ." 7 ,. -

Design ~ h i l o s o ~ 1 1 ~ \ * ~ ~ H ! C L Efi.:?, n!r~,.sg2 < .'4- ,;1

- I r/\

&I\T "'ktf!1cLE S:-S'i4 E i ' D S U J S f ~ f i i T zz f 1

T he J -2 e ngine i s the s e c ond ma j or p ropu lsion - -& I

sys te m de ve loped us ing l iqu id hydroge n a s the fuel .F i g u r e 9. Sa tu rn V, Engine/S-LT St age .Applicati on

Developm ent of the 5-2 engine was under take n to

5ati sfy the need for a high -thru st, high-perforlPn-

anc e upper s tage engine which would be capable of I t was dec ided in the ear ly s tages of the Apollo

,r e $ & r t i w in, pace. Prdpe l lant ut i r iza t ion and Pr og ra m tha t the engines for the second and

t h ru s t ~ r o g r a m ~ n i n ge qu i r e d a n a dd i t iona l f l e x i - third s tages would be comple te ly inte rchangeable .

bi l i ty fo r the engine sys tem., Much of the exper- The J -2 engine requi res only minor changes to

iec ce and technology ga ined on the RL-10 P rog ram per mi t appl ica t ion in the second and thir d s tag es .wa s d i r e c t ly a pp l ic ab le to the J -2 e ngine. Since Changes in the insulation, orificing, and he a t e x -

the J - 2 wa s to be used on a manned vehic le . cons id- changer connect ions a re required, and provis ions

erab le a t tent ion had to be given to achieving a high mus t be ma de fo r r e f i l ling the hydroge n s ta r t bo t t le

re l iab i l i ty through ex tens ive component and engine fpr the S-IVB res ta r t .

sy s t em s ground tes t ing to reso lve a riy potent ia l

pro ble ms before f l ight tes t ing. In the des ign of

the 5-2, a t tea t ion has been focused on potent ia lDescr ipt ion

fa i lu re 111odes and inhere? t des ign ch ar ac t e r is t i cs The J -2 rocke t engine , shown in Figu re 10,

whic h c ou ld p re ye n t the se f a i lu re s ; - Welded joints i s a 230 , 000-pound th rus t , mul t ip le - re s ta r t ,

a r e used throughout the engine to prevent leaks . gimballed engine utiliz ing liquid hydrogen and

D ua l s e a l s , w it h i ~ l t e r m e d i a t e l e ed s , a r e us e d

- a t a l l h ot g a s and prope l lant separable connec t ions .

1

5



' ' . l iq u i d o x y ge n a s p r o p e l l a n t s a n d is d e s i g n ed t o b e

u s e d s i n g u l a r l y o r c l u s t e r e d . T h e e n g i n e h a s a

r e g c n e r a t i v e l y c o o l e d t h r u s t c h a m b e r , . s e p a r a t e

LHZ a n d LO X p u m p s d r i v e n b y a g a s g e n e r a t o r

c o ~ e c t e dn s e r i e s t o t u r b in e s p ow e ri n g e a c h

p u m p , g a s e o u s h y d r o g e n f o r e n g i n e s t a r t , a n d a n

i n t e g r a l h e l i u m c o n t r o l b o t t l e f o r p n e u m a t i c v a l v e

o p e r a t i o n . An e l e c t r i c a l c o n t r o l a s s e m b l y ( E CA )

p a c k a g e c o n t r o l s t h e e d g i n e s e q u e n c i n g a n d p r o -

v i d e s t h e h i g h v o l t a g e t r a n s f o r m e r s f o r t h e s p a r k

ign i t ion sys t em.

C

T h e m a j o r p a r a m e t e r s a r e s ho wn i n F i g u r e 11.

fo r f l i gh t eng ines . Bo th the f i r s t f l i gh t conf igu ra-

t ion and !he uprate d configurat ion eng ine s have

been qual i f ied . T h e f li g h t t e s t p r o g r a m t o c s t a b -

l i s h o v e r a l l v e h ic l e p e r f o r m a n q e h a s v e r i f ie d t h e

eng in e ' s f l i gh t capab i l i t i es . The 5 -2 eng ine has

b e e n u n d e r d e v e l o p m e n t f o r a l m o s t e i g h t y e a r s .

E x t e n s i v e c o m p o n e n t a n d s y s t e m t c s t in g h a v e

d e m o n s t r a t e d a re l i ab i l i t y of 0 .9950 a t a 50 pcrc cn t .

conf idence l eve l . T h e r e h a v e b e en 3 , 1 8 3 s ing lc -

e n g i n e t e s t s w i t h a n a c c u m u l a t e d t e s t t i m e o f

309 ,140 seconds . T h e r e h a v e b e e n 57 c l u s t e r f i r -

ing t es t s , cons i s t ing of the fu l l f ive-engine c lus -

t e red conf igu ra t ion c o n d u c t ed f o r 1 0 , 1 1 3 s e c o n d s

of f i r ing t ime . T h e J - 2 e n g in e h a s m a d e f o u r

S a t b r n IB f l igh t s and two f l igh t s in t he Sa tu rn V

vehicle.I I~ k u r e2. J -2 E n g in e P r o j e c t M i l e s t o n e s

F i g u r e 10 . 3-2 Engine

Prob lc lns (Non-Fl igh t ) . Th e c o u r s e of t h e J - 2

, devclopment has no t been wi thou t inc iden ts . The

f i r s t en gi ne t e s ~ s x h i bi t ed s i d e l o a d s d u r i n g s t a r t

-a t s e a l e v e l c o n d it io n s ; h o w ev e r , t h e r e h a v e b e e n

. . .

.... .... no s i de load p rob lem s whi l e t cs ti r ig a t a l ti t ude ......

.... .. T h e s i d e l o a d s w e r e d u e t o g a s fl ow s e p a r a t i o n s... . .> L "..., ..,.. i n s i d e th c t h r u s t c h a m b e r . S ince the g imbal ac tua -

.......,.. ...... t o r s w e r e d es i g n e d t o ta k e t h e n o r m a l t h r u s t l o ad ,........ ...-.,. ... .

. . me an s had to be found to con ta in these s id e.. .,. = .~ . l oads . Th i s was accompl i s hed bv modi fy ing the....... .....*.-. with the 'addi t ion of s ide Load r es t r ai n-,- ......

,............ i ng a r m s t o p h y si c al l y h ol d t he e ng i ne d ~ r i n gn -,.,.....: ... .--- -- -............ --

g i n e s t a r t .~ . . ~............

".. .............

. . . . F u e l p u m p s t a l l w a s a d e v e l o p m e n t p r o b l e m.......

: , , .".. e a r l y i n th e p r o g r a n i , The . fue l pump 'f low e n te red .

. . . . . . . . . . . . . .' . > ,. %....*a - I L ..---L- - . .. - . -.., .. h e r e g e n e r a t i v e l y c o o le d j a ck e t b e f o r e p a s s i n g

' in to the in jector . A s t h e fu c l pu m p d e l i v e r e d t h e

F i g u r e 11 . 5 - 2 E n g in e P a r a m e t e r s f i r s t f u el t o t he r e l a t i v e l y w ar n -, c h a m b e r , a c o n -

s i d e r a b l e v o l u m e of h y d r o g e n g a s w a s c r e a t e d . The

D e\ e l o p ~ n e n t r o g r a m g a s c o u l d no t p a s s t h r o u g h t he i n j e c t o r a t a r a t eSign l i t c an t deve lopm ent s wi th ,in th e 3-2 p r o - suffi ,cient to kecp up with the flow. Thc soluLion was

g r a i n a r e s h o w n in F i g u r e 1 2. T h e d e v e l o p me n t . to p rech i l l t he pump and charnbcr .irith l i q u id h y d r o -

t c s t p r o g r a m h a s t h r e e d i s t in c t f a ce t s: C a m p o - g c n t o l i m i t t h e t e n l p e r a t u r e c o n d i t i o n s u n d r r w h ic h

n e n t t e s t i n g , e n g i n e s y s t c n l s t e s t i n g , a n d i l i g h t - a s t a r t w0u.l-d be atte mpt ed.

t es t ing . Th e compo nen t t e s ine, con s i s t s of qua li - .

fy ing a l l maj o r co1nponer ;t s and ver i f i ca t ion t es t ing%



Another pro ble m involved sequencing of the

main liquid oxygen valve opening, allowing an

exc ess ive amount of liquid oxygen to be passed

on to the gas generator . This caused excessive

gas t empera tu re and p re ssu re sp ikes in the

gas generator . The problem was corrected by

changing the sequencing of the main liquid oxygen

valve to a id in reg ulating the flow of liquid oxygen

to the gas generator . This has a lso helped to

alleviate the previously discussed fuel pump Stall

p r o b l e m

Thr ee ser iou s component problems which

occ brre d during the development of the J-2 engine

wer e ECA solder joints fa i lures , LO X turbine

wheel cra cks , and ECA t im er fai lures.

ECA Solder Joint Fa i lu res . Spurious engine

cutoff signa ls wer e enc ountered during checkout

of a vehicle at Cape Kennedy. The signals we re -

trac ed to crack ed sold er joints in the engine ECA

pacKage. The elect r ic al control assembly, whish

i s the ner ve cent er of the engine, sequences the

engine operations throughout the complete cycle.

i

As shov..n in Figu re 13, the cr ac k occur red in

a joint w her e a component was solde red into a

pr inted ci rcui t board. Subsequent temp erature

stre ssi ng ca used the joint to fail a s shown in Fig-

ure 14.

BASE EYELET

4 RINTED CIRCUIT

CONDUCTOR

Figure 14. Typical Solder Joint Fai lure

Since this had been recognized a s a potential prob-

le m ar ea , a subst i tu te shown in Figure 15 was

being developed in the production support program.

The termin al sol id pin a cts a s a heat s ink and re-

sul ts in a va stly improved joint in which mic rosco pic

cra ck s that ar e no deterren t to good continuity ar e

occasionally encountered.

+ SOLDER JOI,

Figure 13. EC A Solder Joint Crack

Fi gu re 15. Improved Solder Joint Design

LO X Turbine Wheel Cracks. Cracking was

detected during a routine inspection of the second

stage LOX turbine wheel (Figure 16).



Figure 16. LOX Turbin e Wheel

FAILED TRANSISTOR Q2

( C K 6 5 ) F R O M J 2 0 8 4 TIMER

( I MMEDI ATE T IME O UT)

V IE W L O O K I N G F R O M

BOTTOM OF TRANSISTOR

CASE-HEADER 8 CHIP

REMOVED.

4 0 X,080_/t_

1 R A Y T H E O N

TI N / S i 02 WHI SKER

IN i2:oo P'OSITION

, \ C K 6 5 APPROX DIA. -< 001

TRANSISTOR APPRO X LENGTH -.010

(Actual Size)

As shown in Figure 17 the wheel hub was cra ck ed

around the ent ir e peripher y. Since this wheel Fig ure 18. F ai led ECA T i m e r T r a n s i s to r

opera ted a t about 8 ,000 rpm, the potentia l energy

avai lable could cause ca tas trophic re sul t s i n ca se This whisker growth is a c ha ra c t e r -of failure. It was disco vered that in going through isti c of noble bas e metals such as t in, indium,the mixture ra t io excurs ion on the J -2 engine, a read and s i lver . The growth i s known to be acc e l -standing wave was ge nera ted in the turbine wheel e ra t e d by (x-ray) , mois ture , e lec t r ica~cpoten2n-which continued to flex the metal a t the hub ar e a ial difference, and the pres ence of si l ica. Sinceunti l fat igue occu rred . BY changing the web thick- ' the t rans i s tor ha s a t in pla ted case , contains s i l i ca

ness and the st i ffening characterist ics of the wheel ge l de s i c c a n t is assembled in an uncontrol led hu-- -the destruct ive standing wave vibrat ion was el im- miditxen3,ironment, ha s a poor her me tic seal, and

--.----p..-p.

Enat&-- - -

- . i s exposed to an e lec t r ica l potentia l di f fe rence i t- .makes an exce l lent t es t -bed for whisker growth.

-

The re was concern over replac ing a qua li f ied com--, - 8 7 -2 -------- \ w - 7 -r-- -- ponent which had 2296 engine hot fi r e tes ts f or a

' ..._-- . fir-<

;>demo nstrated rel iabi l i ty of 0.9999 at a 50 perc ent

- -,/. --- , confidence level and 50,000 ex posure s in no=-hot../.a ,-- - . ~ . f i r e t e s t s f o r a rel iabi l i ty of 0. 9998 at a 50 per -.-.L:---'-1.

cent confidence level . Th is is another example

of the A pa lo prog ram pushing the s ta te of the a r t .

The t rans i s tors wer e the bes t ava i lable in the

indust ry a t the t ime they were chosen for the ap-

pl icat ion. However, th e long lead t im e involved .

in manufac turing an i t e m a s compl ica ted a s the

Saturn V vehicle resul ted in long s torage t im e fornumerous sub-components . This t ime per iod was

sufficiently long enough to allow the whisker to

grow to the extent tha t i t caused a short be tween

the t rans i s to r e lement and the case . The t r a ns i s -

to rs w ere rep laced with a high re l iabi l i ty improv ed

uni t made under mor e r igid manufac tur ing sp ec-'

Fi gure 17. LOX Tu rbine Wheel Hub Cra ckificat ions and with a c as e mater ial which did not

suppo rt whisker growth.

EC A T i me r Fa i l u re s . An e l e c t r i c a l c on t ro l

a s s e n ~ b l y imer fa i lure occu rred during checkout

at Cape Kennedy. Throughout the histo ry of the

t imer development encompassing about eight years

only 'e leven fai lu res were noted. Of these fai l ur es

s i x we re a t t r ibu t e d t o t r a ns i s t o r s i n t he amer c i r -

cui t . A thorough inves t iga t ion of th e p r o b j6 ~ i t -

t ributed th e caus e to be whisker growth wiF1Gn

the ca se enclosing it CI< 65 t rans i s tor w&+ is an '

integ ral pa rt of the t ime r. The urhisFer &.r?wthis shown in Figure 18. . .

P r ob l em s ( F l i g x .

AS-203 hot cro sso ve r duct. Fl ight data

f r o m AS-203 indica ted tha t the c ro ssov er duc t

(See Fig ure 10) which con nects the fuel turbin e

to'the oxidizer turbine did not cool a s rapid ly

as ant ic ipa ted and the addi tiona l energy in thesys tem inf luenced the engine s ta r t t rans ient .



.

Due to exce l l en t h ea t t r an s f e r ch a r ac te r i s t i c s in

a sea level environment , the duct had alway s

cooled quick ly before a r es ta r t te s t was in i t ia ted .

Tes ts wer e conducted a t the Arnold Engineer ing

Development Center in an environmenta l te s t ce l l

in which the en t i re Saturn S-IVB s t ag e can be

mainta ined a t a s imula ted a l t i tude of 100 ,000 fee t

d u r in g en g in e s t a r t t r an s i en t an d s t ead y s t a t e ,operation. These t es t s ver i f ied that the J-2 en-

g ine would s ta r t and r es ta r t sa t is fac tor i ly under

l a rg e t emp era tu r e ex t r em es by s t a r t in g wi th th e

prope llant util ization valve wide open. Th i s o p e r -

a t ion in s u red min imu m en e rg y in th e s y s t e m a ts tar tu p s ince the engine would be program med for

an in i t ia l fuel r ic h mixture ra t i o which would put

le ss heat in to the gas ge nera to r tu rb ine exhaus t

gases tha t pas s th rough the cross ove r duct . In

addit ion the cr oss ove r duct was pain ted b lack to

enhance the tra ns fe r of heat out of the syste m.

AS-502 Fl igh t . Anomal ies were encountered

in both thc S-II and S-IVB s tage s dur ing f l igh t .

The S-I1 anomalies included environmental

changes, indicated yaw actuator malfunction, p er -

formance s h if ts , and pre mat ure cu tof f.

Environmen tal Changes. The 502 flight wa s

norlnal by 501 s tan dar ds until 225 seco nds afte rl l i to f f . At tha t t ime te mpe rature began to dro p

rapid ly in sc lec ted engine ar ea s a s shown in Fig-

ur es 19, 20, and 21. Engine 2 cutoff was pre -

ceded 0.3 seconds by indications of hot ga s im-

pingement a s depic ted in Fi gur es 22 and 23 .

tngine 2 1l)draullc rlufd Teqcr turer

flr sl llnrusl Second TnrustSl,t11 Shill

-1% r I

xa

Time frola Lill~f lsecl

~. . . . . .

Figure 19 . Cool ing Trends P r i or to Engine

Number 2 Cutoff

Cool ing t rends were es tab l ished by 2S0 s eco n d s

a f t e r l if to ff and were acc elera t ed a t 320 seconds .

Eoth t ime in ter \ .a ls cor respond c losely wi th th rus t

sh i i t s . J u s t p r io r to engine number 2 cutoff the

engine and thrus t cone ar ea indicated hot gas im -

pingcment. Following engine nu kb er 2 cutoff th er e

was a cooling trend $11the engine 2-5 qu adrant in l

dicating a cryogenic l ine rup ture .

fIN C

.Fig u re 2 0. Bottom View of Area Cooled Prior to

Engine Number 2 Cutoff

-

I

+ 113 sec

Fig u re 21 . Side View.of Are a Cooled Pr io r to

Engine Number 2 Cutoff .l l N A

Fig u re 2 2. Bottom View of Ar ea IIeatcd and

,Cooled at Engine N umber 2 Cutoif



F i g u r e 23. S i d e V i e w of A r e a s H e a t e d a n d C o o l e d

a t E n g i n e h T u mb e r 2 Cutoff

T h e m o s t p r o b ab l e s u s p e c t s f o r c a u s i n g this

t y p e of a n o m a l y i s a l e a k i n t h e a u g n le n t ed s p a r k

i g n i t e r (ASI) f u e l o r o x i d i z e r l i n e w i th t h e f u e l

l i n e t h e p r i r n e c a n d id a t e. ( F i g u r e s 24, 25, 26,

and 27 .

F i g u r e 2 4 . 5 - 2 E n g i n e I g n it i o n S y s t e m

It h a s b e e n p o s t u l a t ed t h a t a s lmal l leal< oc -

c u r r e d i n t h e l i n e 2 n d co n t ln u c d t o n i a n i f e s t i t s e l f

u n t il t h e r e c r a s a c o i n p l e t e r u p t u r e . At t h i s p o i n t

h o t g a s e s f r o m t h e c o i nb u s ti o i l c h a m b e r w o u ld

b a ck f lo \ v t h r o u g h o n e l e g o f t h e r u p t u r e d l i n e i n

the v ic in i ty o f the AS1 p o r t a n d r e s u l t i n h o t g a s

s p e wi n g o u t o n e p a r t of t h e b r e a k a n d r a v c r y o g e n i c

p r o p e l l a ~ t o m i n g ou t o f t h e o t h e r s e \ - e r e d en d .

T h i s p h e n o m e n a h a s n o t b e e n c o n l p l e t e ly d d p l i c a t e dunclcr c on t r o l l ed co l id i t io~l s t t il e t i me t h i s p a p e r

w a s w r i t te n .

F i g u r e 25 . L o w e r e n d o f ASI F u e l L i n e

F i g u r e 26 . Uppe r end of AS1 Fuel Lin e

F i g u r e 27. AS1 LOX Li ne



Indicated Yaw Actuator Malfunction. As shown

in F ig u r e 2 8 , co inc id ent wi th a sh a r p in c r ea se in

cool ing , t he yaw ac tua to r AP b e g a n t o i n c r e a s e

r ap id ly an d r each ed a m ax im u m p o in t co r r e sp o n d -

in g to th e seco n d th r u s t sh i f t ex h ib it ed b y th e en -

gine. I t was postu la ted t ha t the ind ica ted mal-funct ion was the r es u l t o f a c ryogenic p rope l lan t

l ea k in th e v i c in i ty of t h e ac tu a to r .

An a c t u a t o r p r e s s u r e t r a n s d u c e r w a s s u b j e c te d

to a s t r ea m of l i q u id n i t r o g en to s im u la t e a l iqu id

h y d ro g e n l e a k i m pi n ge m e nt . T h e p r e s s u r e t r a n s -

d u c e r ( F i g u r e 2 9 ) i s c o m p o s ed of t wo c o n c e n t ~ i ch e l ix b ou r d on p r e s su r e tu b es w i th o n e a t t ach ed to

th e d ash p o t wa l l and th e o th e r f a s t en ed to a s l i d -

ing rod . As th e o u te r h e l ix tu b e co oled r ap id ly

i t co n t r ac t ed f a s t e r t h an th e in n e r t u be an d g av e

an in dica t io n of a d i f f e r en ti a l p r e s su r e . As th e

in n e r h e l ix tu b e ap p r o ach ed th e t em p er a tu r e o f

th e o u te r o n e , t h e t r an sd u ce r i n d ica t ed a n u l l

posi t ion . When the cryogenic so urc e was re&&ed,

th e p r o ce ss wab r ev e r s ed wi th th e o u te r t u b e h ea t -

in g u p f a s t e r , ex pan din g, an d giving an e r r o n eo u s

d i f fe r e nt i a l p r e s s u r e . A s t h e i n n er tu b e t e m p e r -

a tu r e ap p r o ach ed th e o u te r o n e a n u l l p o s i t i o n was

again in i t ia ted . I t i s b e l i ev ed th at t h e c r y o g en ic

sp r ay of t h e ac tu a to r A P t r a n s d u c e r a n d / o r a n

engine per fo rma nce sh i f t cou ld exp lain a l l thein d ica t ed yaw ac tu a to r an o m a l i e s .

F i g u r e 29. Pic t o r i a l Sch em a ti c of A P T r a n s d u c e r

,Mt4n V ~ ? l

I uelFiavRd e' ~ l t g l d D2ta

318 3 32! 1"_-. - - , - 2 - - --

Time Fro- ~ n ~ i fred

Fig ure 30. Engine Number 2 Thrust Sh if t

Ir. Srcnnd T l i r u s l Shill Pr em at ur e eng ine cu tof f. Engine numbe r 2

: Fw s l I t ~ r ~ ~ s ll n l t f.Csy~rw Cut011

-MOD ' cutoff a t 412. 8 seco n d s an d en g in e n u m b er 3 cu t -*% 215 3~ 325 3% 375 dW A15 4 3 675

off at 414. 28 seconds a f ter l if to ff which was shor t

Ranyc l t s l e {rrO of the requ i red m iss io n burn t ime by 107 seconds

and 105. 5 seconds respect ive ly . The reas on for

F i g u r e 28. Yaw Actuat or A P t h e n u m b er Z engine cutoff was activation of Lhr

m a i n s t a g e t h r u s t 0 . K. p r e ss u r e swi t ch wh ich h ad

- P e r i o r m a n c e Shifts. Three pej-forlmallce shif ts d ecay ed to th e cu tof f l ev e l a s a r e su l t o f t h e m a l -

o c c u r r e d d u r in g t h e S-I1 burn . The f irst shif t v ,ras funct ion(s) . Eilgine 3 was cu toff a s a resu l t of a

g r ad u a l s t a r t i n g a t 2 60 se co n d s a f t e r l if to ff an d human er ro r in the s tag e assem bly . IIThen so lenoid

cont inu ing for about 60 seconds t o a m a x i m u m o f swi tche s we re c llal lged ou t o f the s tage the LOX

6 psi d rop , A sudden 20 p s i deckease in cllalllber prevalve contro l co lnmand cab le on the number 2

pr es su re occ ur r ed approximate ly 319' seconds af ter" lg ine was er r oneo usly connected to the number

l i f t o f f , an d a 10 psi drop o c c u r r o f i 0, seconds be- 3 engine so lenoid and the cu tof f s ig nal in i t ia ted

fo re cutoff of the num ber 2 engillei As sh own in in the nu lnber 2 engine prevalve contro l c i r cu i t

F i g u re 30 , a l l p a r a m e t e r s i n d i c q ~ d d r o p i n shutdovm engine number 3 .

t h r u s t a t t h e 3 19 seco n d da ta s l i $ Su.h i ch was c lo se -

l y s i~n u la t ec l y t h e m a th m o d e l wh en p r o g r a in m ed AS-502 Anornalics (S-IVD --t a g e ) n o l ~ ~ x l i e s

f o r a l a i g e f u e l le a k . A p r e l im in a r y ' co n c lu s io n wh ich o ccu r r e d on th e AS-502 f l ight in the S - I VB

i s tha t a leal\ in t h e ASI f u e l ine caused tile anolnaly . s tag e inc lude per form ance sh i f t r lu ri rlg f i r s t burn ,

A,, ex tensive tes t p rogra l, l i s s t i l l in progre s s .to changes in env ironm enta l condi t ions dur ing f i r s t

comple te ly ver i fy the c aus e of th e malfunct ion .b



b u rn , h y d rau l i c s y s t em f a i lu r e , an d f a i lu r e o f th e engtne. A s a re su lt of an intensive s implif ica ' t ion

en g in e to r e s t a r t o n s eco n d b u rn . p ro g ram , th e J - 2 en g in e i s p ro g rammed fo r a

demo ns tra t ion of des ign ' in an upra ted vers ion in

Th e f i r s t b u rn o f th e 5 - 2 e n gi n e w a s n o r m a l u p t h e 1970 time f r a m e .

,--- to 695 s eco n d s a f t e r li ftof f. A t th a t t im e th e r ewas a n eng ine p e r fo rma n ce s h i f t an d a d i s tu rb an ce --

/ in environmenta l condi t ions .

T h e c h a m b e r p r e s s u r e d r op p ed , f u e l p u m p

d i s c h a r g e p r e s s u r e i n c r e a s e d , b o th t h e f u e l and

LOX n j e c t o r p r e s s u r e d e c r e a s e d , t h e f u e l in-

j ec to r . t emp era tu r e ro s e , amd t h e fu e l p u mp s p eed

wen t to ze ro rp m. F ig u re 3 1 in d ica te s th a t b o thh ea t in g an d co ol ing o ccu r r ed ex te rn a l to th e en g in e

dur ing a 15 second t im e in terval .

A s h a r p d r op i n t he c y l i n d e r o i l t e m p e r a t u r e

of the yaw actuator was r ecor ded a t 695 second s

to co r r e s p o n d wi th th e p r ev io u s ly men t io n ed en -

v ironmenta l changes .

t

Figure 31 . Su mm ary of Environlllell tal Condition

Changes

All precol ld i tioni l lg r equ irem ents w ere s a t i s -f ac to ry fo r th e s eco n d b u rn an d a l l v a lv es

cy c led p ro p e r ly . T h e s t a r t tr a n s i e n t w a s n o r -

m al un t i l the beginning of main s tage except for

c h a m b e r p r e s s u r e w h i ch f a i le d t o r i s e t o t h e

d es i r ed l ev e l in d ica tin g n o ig n it io n in th e ma in

ch amb er . T h e m o s t p r o b a b l e c a u s e f o r t h e f i r s t

burn anorr la l ies and t t e Cai lure to res tac t i n the

P xc nt n : n r ~ l

.&I'D 01 EEI or A S S I ~ 10 c h r ! Ir rn 1 ~ 7 1 a u l i orC?LhlCb l S1LXi;IED tVGI1:t I W 1970.

\

Fi gur e 32. J - 2 Engine Contr ibu tion .to Saturn V

Pay lo ad In c r eas e

S u m m a r y

c r a m h a s e n -he J - 2 engine development pro ,

countere d problems typ ical of a new prop uls i o~l

unit . To d a te n o p ro b lem h as ap p ro ach ed th e t ech -

n ica l complexi ty of the combus t ion ins tab i l i ty phen-

omen a found in the LO X-RP-1 engines . T h e p r e s -

ence of two cryoge nics mak es the dynamic balance

of the propuls ion s ys te m under a wide opera t ing

band a ve ry d i f f icu lt p roblem espe cia l ly dur ing the

s t a r t t r an s i en t p h as e . Th e b as i c en gin e d es ig n h as

beell thoroug hly evaluat ed and tested.

Fu tur e Outloolr .

Th e develop ment of l iquid oxygen-liquid hydrogen

engines is b u t an o the r t i ck m ark in th e ln i l e s to n es

of propuls ion , The pas t t rend ha s been to la rg er

engines bu t now a p la teau se em s to be forming .

F or the nea r fu ture , developments wi l l p robably

ev o lve a lo n g mo r e v e r s a t i l i t y in th e s y s t em, h ig h e r

imp ulse , and m or e re l iab i l i ty . One of the mo s t

p ro mis in g f i e ld s i s t h e lo w co s t b o o s te r u t i l i z ing

e i th e r p ack ag ed s to r ab le s o r s o l id p rop e l l an t s .

second burn i s a n AS1 fuel l ine f a i lu re . MathAcknowledgements

m o d el s p r od uc e s i m i l a r ~ e r f o r l n a n c e hi f t s fo r

fa i led AS1 fu e l l in es ; h o wev er , a l l ma l fu n c tio n s Th e a s s i s t an ce of th e man y p eo ple who co n t r i -

have not 1-e t been sa t i s fac tor i ly expla ined . T e s t buted to the prepara t ion of th is paper i s appr eci-p r o g r a m s a r e u n d er w a y t o d e m o n s t r a t e f l i gh t a ted . Th e au thor would par t icu la r ly- l ike to thankfa i lu r e mo d es .

p e r s o n n e l in th e Pro p u l s io n an d Veh ic le En g in ee r -

in g Lab o ra to ry an d o th e r l ab o ra to r i e s a t t h e

Uprating Mars h a l l Sp ace F l ig h t C en te r an d th e man y Sa tu rnCons is ten t wit11 the pa t ter n of the o ther la rg e c o n t r a c t o r s wl-?p contr ibu ted data and analyses for

liquid engines developed by NASA, the J-2 engine th e p r e l im in a ry co n c lu s io n s d r awn in th e f lig ht

- h a s b e en s t e a di l y i ~ n p r o v e d i n c e i t s c o n r ep t i on p r a b l e r n a r e a .

and contributed marlied1)- to vehicle payload in-

c r e a s e s a s s ho wn i n F i g u r e 32. Pay lo ad cap ab i l -

i ty in th e Sa tq rn V v e hi c le h a s b e en i n c r e a s e d a l -

m o s t 7000 lbs . ih rough improvexnents in the 3-2

Development of LOX-Hydrogen Engines for the Saturn Apollo Launch Vehicles

Documents

Transcript of Development of LOX-Hydrogen Engines for the Saturn Apollo Launch Vehicles