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@[email protected].
• 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