ApolloSystemArchitectureDecisionProcess

HowCanWeGetToTheMoon?Sourcedfrom“selec@ngtheWayToThe

Moon”byJohnLogsdonandNASASP-4009

hKps://www.hq.nasa.gov/office/pao/History/SP-4009/v1p2c.htm

FlemingCommiKee2May–16June

1961•  Tenta@vePlan(1ststagesta@s@cs,usingF1engine)–  C1(1.5MlbfF1)1964,Earthorbit

–  C3(2x1.5MlbfF1)1965,LunarOrbit

–  Nova(8x1.5MlbfF1;160,000lbstolunarescapevelocity)1967,Lunarlanding

LundinCommiKeeInstruc@ons25May1961

•  Allpossibleapproachesforaccomplishingthemannedlunarlandingmissioninthe1967-1970periodshouldbeconsidered.

•  Primaryemphasisshouldbeplacedonthelaunchvehiclepor@onofthesystem:vehiclesizeandtype,theuseofrendezvous,etc.

•  Nuclear-poweredlaunchvehiclesshouldnotbeconsideredforuseintheearlymannedlunarlandingmissions.

•  Advantages,disadvantages,andproblemsassociatedwitheachtechniqueshouldbeindicatedand,basedonthese,arela@vera@ngofthevariousmethods.shouldbeestablished.

•  The@mephasingandaroughorderofmagnitudecostshouldbeindicatedforeachmethodconsidered.

•  Thestudyshouldbecompletedataboutthesame@meastheoneunderwaybytheAdHocTaskGrouponMannedLunarLandingStudy.

HowcanwegettotheMoon?

LundinCommiKeeFinding

•  Directascent•  Earthorbitalrendezvous(EOR)•  Lunarorbitrendezvous(LOR)•  Lunarsurfacerendezvous

Twomethodsoflandingtechniquesproposedforthedirectascentmoseforthelunarlandingmission

preferred

HeatonCommiKeeJune1961

•  NASAHQandNASACenters–inves@gateEORop@ons•  “...thatearth-orbitalrendezvousofferedtheearliestpossibilityforasuccessfulmannedlunarlanding.”– WorkedwithC3rocketconcept–  Andofferedalterna@ve4engine(C4)scenario,becauseC3wasimmatureandC4providedmorelihandthusmoremargin

•  RosencommiKeeinNov1961:“spacerendezvouspresentsthepossibilityofaccomplishingtheini@almannedlunarlandingmissionearlierthanbyanyothermeans..."andthat"thepreferredrendezvousmodeisthesinglerendezvousinearthorbit.”Added–therecommenda@onof5enginefirststagerocket.

LORStudies

•  Ideagoesbackasfaras1916and1948•  GroupatLangleyResearchCentertaskedwithfleshingoutdetailsofLORearlyas1959

•  Voughtastronau@cswasworkinginparallelonLORscenarios,neithergroupknewaboutothereffort

•  JohnHouboldtwasa@reless(fana@c?)advocateofLOR

Storycon@nues...

•  28November1961contractforCommandandServiceModulesawardedtoNorthAmericanAvia@on

•  15-21December1961Boeinggivencontractforfirststagewith5F1engines(5x1.5M=7.5Mlbsthrust)–nowcalledC5.

•  Whataboutupperstages?

S@llnodecisiononarchitecture!

LOR?•  March1962groupformedatMarshallSpaceFlightCenter

studyarchitectures:–  Establishrealis@cschedulesthatwould"secondguess"failuresbutprovidefor

exploita@onofearlysuccess.–  Schedulecircumlunar,lunarorbit,andlunarlandingmissionsattheearliest

realis@cdates.–  Completetheflightdevelopmentofspacecrahmodulesandopera@onal

techniques,usingtheSaturnC-1andC-1Blaunchvehicles,priortothe@meatwhicha"man-rated"C-5launchvehiclewouldbecomeavailable.

–  Developthespacecrahopera@onaltechniquesin"buildup"missionsthatwouldprogressgenerallyfromthesimpletothecomplex.

–  Usethespacecrahcrewattheearliest@meandtothemaximumextent,commensuratewithsafetyconsidera@ons,inthedevelopmentofthespacecrahanditssubsystems.

•  2-3April1962–NASAHQbriefedonLORanditsbenefits•  MarshallvsLangley!EORvsLOR!

JohnHoubolt,promoter,notinventorLRO

LORItIs!•  22June1962VanBraunandMarshallreversecourseandsupportLOR

•  NASAtena@velyacceptedthedecision,lotsofpush-backfromwithinandoutsideofNASA

•  Decisionconfirmedon7November1962•  GrummanAircrahEngineeringselectedtobuildlunarmodule

JamesWebb:“despitetheveryextensivestudyefforts, . . .wearedealingwithamaKerthatcannotbeconclusivelyprovedbeforethefact,andinthefinalanalysisthedecisionhasbeenbaseduponthejudgementofourmostcompetentengineersandscien@stswhoevaluatedthestudiesandareexperiencedinthisfield."

Saturn5FunFactstoKnowandTell

•  3StageRocket– 1ststage,5F-1engines,7.8Mlbf(SI-CBoeing)

•  2000metrictonspropellant(RP-1andLOx)

– 2ndstage,5J-2engines,1.15Mlbf(S-IINorthAmerican)•  440metrictonspropellant(H,LOx)

– 3rdstage,1J-2engine,0.23Mlbf(S-IVBDouglas)•  109metrictonspropellant(H,LOx)

•  PayloadtoLEO(140metrictons)hKps://history.nasa.gov/SP-4029.pdfApollobytheNumbers,Orloff