Saturn 1B Launch Vehicle Flight Evaluation Report, SA-206, Skylab-2

8/8/2019 Saturn 1B Launch Vehicle Flight Evaluation Report, SA-206, Skylab-2

1/230

SATURNMPR-SAT-FE-73-3 JULY 23, 1373

le) SATURN 16 LAUNCH w73-33820EVALUATION EEPOET, SA-206,230 p NC 513.50 CSCL 22c UaclasG3/30 19942

SATURNB LAUNCH EHICLEhl6tlT EVALUATIONEPORT-$A-20

SKY AB-2

?RE?AREDBYSATURBFll6H1 EiALUAtlOl WOF.KM6 6QOUD

- Form 774 (Rev October 1967)


2/230

6EOR6EC. NARSHALLSPACEFLIGHTCENTERMPR-SAT-FE-W3 JULY 23,1973

SATURN B LAUNCHVEHICLEFLIGHTEVALUATIONREPORT-$A-206SKY AB-2

PREPARED YSATURNFLI6HT EVALUATIONWORKING ROUP


3/230


4/230

MPR-SAT-FE-73-3SATURN IB LAUNCH VEHICLE FLIGHT EVALUATION REPORT - SA-206

SKYLAB-2BY

Saturn Flight Evaluation Working GroupGeorge C. Marshall Space Flight Center

ABSTRACT

The Saturn IB, SA-206 launch vehicle was launched on Mav 25, 1973, fromKennedy Space Center and placed the Command Service Module Containingthree crew members into an 81 x 190 n mi. earth orbit. No anomaliesoccurred that seriously affected the mission.

Any questions or comments pertaining to the information contained inthis report should be directed to:Director, George C. Marshall Space Flight CenterHuntsville, Alabama 35812Attention: Chairman, Saturn Flight Evaluation WorkingGroup, SAT-E (Phone 205-453-1030)


5/230

PRIXDING PAGEBUNK~PILUH,

TABLE OF CONTENTS

TASlE OF CONTENTSLIST OF ILLUSTRATIONSLIST OF TABLESACKNOUlEffiEMENTABBREVIATIONSMISSION PLANFLIGHT SUMARVMISSION OBJEC TIVES AC[X)IPLISlMNlFAIlJMS AN0 ANWALIESSEC TIO IY 1 - 1NTKWUCiICBl1.1 Purpose1.2 ScoreSECTIW 2 - EVENT TIMES2.1 Smnary of Emntt2.2 Variable Tl w and r---'-d

Suitch Selector EventsSEC TIm 3 - LAUJCH OpERerlIollf3.1 S-rY3.2 Prelaunch Wlcstones3.3 Tenninrl Countdan3.4 Propellent Loadlq3.4.1 Rp-1 loadiq3.4.2 LOX Loadlq3.4.3 lH2 Loading3.5 Cmund Support Equlm t3.5.1 Ground/Vehlcre Interface3.5.2 MFC Furnished 6mued SuppcrtEwfpccctSECTl(cI 4 - TWECTURV4.1 -av4.2 Trajectory EvaluWon4.2.1 Ascent Phase4.2.2 Partlq Orbit pbneSECfloN 5 - s-IvB/IU BEom IT mMvslS5.1 mry5.2 Beorb1tIlanewen5.3 OLorblt Tmjectovy Evalrutim

Page

l-ll-ll-l2-l2-l2-13-13-l3-l3-l::;::::::3-44-l4-I4-l:::5-lS-l5-l5-2

5.4 Impac t FootprintSECTIUN 6 - S-IB PROPULSICM6.16.2

S-WVS-18 Ignitfon TransientPerfomanceS-IB Ualnstage PerfomanceS-16 Shutdarn Transie ntPerformanceS-18 Stq e PropellantNanagenen tS-IB PnssurlratonFuel Pressurtzation SysteuLOX Tank Prcssurlratlonsys ternS-IB Pnematlc ControlPressure systmS-18 Hydraulic Sys tq

6.36.4

6.5

i-i 16:6:2

6.76.8SECTIOR 7 - S-IVB PROPUSIOII1.17.27.37.47.5

Z.17.6.27.7

7.0

1.9

SmhsryS-IV B Chllldm~ and BulldupTransient PcrfomanceS-IVB Mnstqe pCrf0Nnc.eS-IVB Shutdarn TransientPmformmceS-IVB Stage PropellantUanqenentS-IVB Pmssurlratlon SystemS-IVB Fuel Pmssurlzatbnsystas-IVB LOX CrnSUl iwtlonSystens-IVB Pmlrw tlc ControlPressure systemS-Iv8 Auxiliary PmpulslmsystemS-IVB/IU Stqe Ueorbitpropellant DupS-IV8 OmItal faflq OperationFuel Tank SrfiqLOX Tank Safiq- _.

7.107.10.17.10.27.10.3 Cold Mliu lhq

PW5-26-l6-l6-l6-l6-76-76-116-116-11

6-136-137-l7-17-27-27-57-S

:::7-77-g

7-127-127-177-177-197-M

iii


6/230

7.10.4 Stage Pneumatic Contml anarngine Control Sphere Safinq7.10.5 lnoine Control Snhcrc Safinq

7.11 5- IVR qardui I(: systmSECTION P - STRUCTIJPESA.1 SumnaryR.2 Total Vehicle Structure s

Evaluation8.2.1 Loyitudinal LoadsB.2.2 Bendinq MomentsA.2.3 Combined Loads0.2.4 Vehicle Dvnanic CharacteristicsSiCT1l-M 9 - Gl'lC!A:!Cf AN@ NAVIGATION9.1 Sumnary9.2 Guidance ComparisonsG . 3 Kaviqation and Guidance Schenr

[valuationQ.'.l first Staqe Boostq.7.7 Second Stage BoostI'_ 7. 3 Orbital Phase?.E Deorhit PhaseNavigation and Guidance SystemCowmentsa.d.1 ST-124M Stabilized Platfomsys teal

9.4.2 Guidance and NavigationCumputerSECTIO N 10 - CONTROL AND SEPRR RTI(II

TABLE OF CONTENTS (CONTINUED)

10.1IO.210.310.3.110.3.210.3.3

10.410.510.5.110.5.2

SmmaryS-I@ Control Systcn EvaluatfnnS-IV0 Control SystnnEvaluations-IVB contm1 SystelnEvaluation During BumS-IVB Control Syst m~Evaluation During OrbltS-IVB Contml SystcnEvaluation Durine Deorbit

10-l10-l10-l10-tIO-2in-7lo-14

lnstrwnt Wt CentralCanponents Evaluation

lo-18

Separation lo-18S-IB IS-IVB Separation 10-18S-IVBKS H Scparrtlon 10-18

Paae7-20 SECTION 13 - VEHICLE THERMAL ENVIRONMENT7-:n7-21R-1R-1A-lA- 1R-lA-3R-f?9-l9-lq-1Q-3

13.1 S-IB Base HeatingSECTION 14 - ENVIRONMENTAL CONTROL SLWARV14.1 5-v14.2 S-18 Envimrmen tal Control14.3 1U Enviromnental Contml14.3.1 i;t,n;sl Conditioning Systm14.3.2 Gas Bearing SubsystemPerformanceSECTION 15 - DATA SYSTEMS15.115.215.2.1

SumaryVehicle Measurement EvaluationGym Sunnation Current andAcceleraneter SunnationCurrent Measurewent level Shift

15.315.3.115.3.2

Airborne VHF Teleme try SystemEvaluationS-18 Telnnetry Systs loss ofSynchronizaticnIU Telcnetry Systm Reductfonin RF Radiated PaverC-Band Radar System EvalwttonSecure Range Safety CamandSystcns EvaluationDigital Camand SystcnEvaluationGround Engimrlng Cncras

16 - MASS CHARACTERISTICSS-rYMass Evaluation

9-59-59-59-99-99-99-10

SECTIO N 11 - ELECTRICAL NETWRRS mtl 11-1EMERGENCY WECTION SVSTEM

11.1 Smmary 11-l11.2 S-IB Stage Electrical Sys- 11-111.3 S-IVB Stage Electrical Sysm 11-211.4 Instrwent Unit Electrical 11-Zsys ton11.5 Saturn IB Errqen cy Detection 11-11systunSEC TION 12 - VEHICLE PRESSURE ENVIKNMN712-112.1 SIB Base Pmssu re 12-l

15.415.515.6

15.7SECTlOll16.116.2SECTIO N 17 - SPIICECRAF T SWMRVSEt TIm 18 - MSFC INFiIGHT EXPERMMTWPENDII( A - ATKWHEREAPPENDIX B - SA-206 VEHICLE DESCRIPT IO(l

Page!3-113-114-i14-l14-i14-314-314-3

15-115-l15-l15-l

15-315-515-5

15-1015-10

15-1215-1416-l16-l16-117-118-lA-lB-l

iV


7/230

Fiaure2-l3-l

3-2b-14-2

4-34-44-5S-l546-l6-2

6-36-4

6-56-66-7

6-R6-gO-10C-116-177-l

7-27-3

LVM clockmouna Tim DifferenceCutoff Anomaly - Simplified ESECircuitryESE Cutoff Annmaly - Te5tResultsAscent Trajecto ry PositionCcmarisonAscent Trajecto ry Space-FixedVelocity and Fliqh t Path AngleCnmParisonAscent Trajecto ry AccelerationComcarisonComparison of Separation Eventslaunch Vehicle qround Tra ckS-IVB/IU Deorbit TrajectoryAltitude (No Breakup A ssuwd)S-IVB/!U Impact FootprintS-IB Engines Thrust BuildupS-M Stage PropulsionPerformanceH-l Engine Position al Gearcaselubricant PressweS-18 Inbcard Enqine TotalThrust DecayS-IB Total Outboard EngineTotal Thrust DecayS-I9 Stage LOK Mass Above MainLOX ValveS-18 Stage Fuel Wass ~baveMain Fuel ValveS-IB fuel Tank Ullaqe PressureS-IB Fuel Tank Meliun Pressuri-zation Sphere PressureY-16 Center LOX Tan k UllagePWSSU?YGDX flow Control Valve PositionS-13 Pneunatic Control PressureS-IVB Start Box and BunRequiremntc - BurnS-IVB Steady-State PerformanceS-IVB LH f Ullage Pressure -Prelifto f. Boost and Bum

LIST OF ILLUSTRATIONS

7-4 S-IVB fuel Pcaxp Inlet Conditions

Page2-23-5

3-64-34-4

4-54-P4-115-25-36-26-3

6-66-B6-R6-10C-10S-126-12

6-146-146-157-37-47-7

7-R

Figure Page7-5

7-6I-7

7-B7-o7-10T-11

7-12

8-l

8-2

e-3

B-4

R-5

B-6

R-7

R-R

8-9B-10R-11

8-12

S-IV B LOX Tan k Ullagc Pressure - 7-9BurnS-IVR LOX Pmp Inlet Condltlons - 7-10BurnS-IV B Cold Uellm SupplyHistoryS-M Rorbit Propellant DIPand Safinq SequenceS-:V B LFX Dunp Param eterHistoriesS-IYB :H2 DumpS- IYB LH2 Ullage Pressure -Ohi tal CoastS- IYB LOX lank Ullage Pressure -b-hit. Dmp . and SafinaSA-206 Lwgitudinal Accclcratlonsat IC ; and CP During ThrustOuild-Up znd LaunchLA-226 LongiLudin ;! Accelerationat the IU and Cu During 5-16CutoffS-lb-6 Longitudinal Load fernStrain Data at Station 942vs. TimeW-206 Lonqitudfnal Load Distri-tutron at iirxe of MaximuxRending Mome nt and IECOSA-206 Bending Manent Distri-butions at lime of Marinuaksultant Moment. T = 65.8ResultantSE-206 Bendinq Manent Distri-hutions at Ti m of WaxinmResultant Ranent. T = 65.8YawSA-206 Bending mnt Oistrl-butions at Tim e of Maxi-Resultant Plnment. 1 = 65.8PitchCombined Lnads Producing Mini-Safety i:argins During M-206Fli(;htVehicle Bending frequenciesVehicle Bending FvnplitudesVibration Measured DuringS-IVB Stage BarnLOX Pm Inlet PressureOscillations During S-IVBStape Bum

7-11

7-147-15

7-16I-1B

7-198-2

n-3

8-3

B-4

R-5

R-6

R-7

R-9

Fl-1DB-11B-128-13

V


8/230

LIST OF ILLUSTRATIONS (CONTINUED)

ClguraEl 3

B-149-1

9-29-39-49-5ID-110-210-3ID-4

10-SW-6lo-710-BID-910-1011-1

11-2

11-3

11-4

11-S11-611-7

Thrust ChaWer PressureOsc lllatlons Durlna S-IV6

PipeB-14

Stage Ilum -S-IV9 la Fmquancy kalysls II-15of Vlbratlon and Eqlnr PressuresTrajectory and ST-124U Platfom 9-2Vcloclty Carparlsons (Tra-jrctory Minus LVDC)Theta v (Pltch) Attltude Angle 9-6Theta 2 (Vau) Attitude Aqle 9-7Theta X (Roll) Attitude Angle 9-BSA-206 ST-124U Platform 9-10System Block Diwrm

Pitch Plane Dpmlcs DurlqS-IB BumVau Plane I&nrlcs DurlqS-III BumRoll Plane Oynalcs DurlqS-18 BumPitch and Vu Plane Fm StreanAqlc of Attack Durlq S-16BumPitch Plane Dynmlcs -S-W UumVu Plane Dyn&cs -S-M gumPitch Plvnc mrics Ihwlq0rb1t(Sheet10f 3)vehicle qmmlcs DurlngDeortdt (she& 1 of 2)s-IB/S-IV6 10qltudlnalAcceleratlalnpular Ve?o cttlcs Ibrlqs-III/S-IVlI Seqrat10nS-IV6 StageFwmardIk. 1Eatery Voltagn. currant,and TslpratureS-IVIIStageFwurdlo.2Sattuy Veltqe. Current,and TslpratufeS-11 Stage Aft Uo. 1 ktteryVoltage, curent. andTemeratn,S-In Sm Aft k. 2 UatteryVoltage. current. andlcrpratourrIU6DlO Uattnry ParrctersIU 6Dxl Uattnry ParrtrrtIU6bSOktteryPar~~ters

ID-310-bID-510-6

ID-8IO-910-1116-1516-1910-M11-3

11-4

11-S

11-6

11-U11-g11-10

vi

Flgum12-112-212.312-413-113-213-313-413-S13-613-714-I14-214-314-414-514-614-714-8

14-g15-I15-215-3

IS-415-S

S-10 St4ge Heat SItlaIdPressumS-10 Stage Flrr ShlcldPmssumS-11 Stage Uaat Shlc ld loadingS-15 Stage Base Drag C0efflcIcntS-16 Stage Ueat Shlc ld InnerRegion Total Heating RatnsS-SB Stage Mat Weld herRegion Radlatlon Hcatlq RateS-16 Stage Heat Weld InnarRegion Gas Tenper8tumS-Ig Stage Mat Shie ld OutnrRegion Gas leqeratumS-ID Stage Flnc Weld Totalrwtiq RatesS-ID Stqa Fln MeldRadi4t1m Herting meS-II Stage Fir Shield Oaslcrplrature

IU Sllnllut0r start UpParmetnrafor Inittal CyrleIll TCS coolant control PINtersIU Tcs Hydraulk Pelam mcewxs~~ fphere PressureInertial Platfom OR2 PressuresIU cm m2 sphere Pressure(DlO-6O3)Ill klectY!d capmentfclpratumsIU selected CopanntTeqmrtulrsS-W WF lelatry Gmundstrt10n C0mageS-11 VW Telatsy CmwdStatIaComrngeIII Tel-try Signa l Strength andylg bOu:;Plots kfom ndPCMTelatry RF PaarOutqt(ReasuraentJ29-6O2)fA-2M IU lelatry RF

ProC12-212-312-412-s13-2l3-313-413-613-713-A13-914-214-414-b14-614-714-814-9IO-1014-11IS-415-415-6

IS-615-7


9/230

LIST 0~ ILLUSTRATIONS (CONTINIJED)

Figure15-615-715-8

A-l

A-2

A-3

A-4

a-5

A-6

A-7

A-8

A-9

B-l8-2El-30-4B-5B-6

Mated RF ConnectorsRF Connector PinsC-Band Acquisition and LossT l ~ SSurface Ueather Map Approxi-mately 1 Hour Before launchof sfi-206/SL-2500 Xillihar Map Approxi-mately 1 Hour Bedore Launchof SA-206,'Sl-2Scalar hind Speed at launchTime of SA-206/SL-2Wind Direction at LaunchTime of SA-206/SL-2Pitch Uind YeT icity Conponent(W,) at launch Tim e ofSA-206/SL-2Van blind Velocity Component.(U,) at Launch Tim e ofSA-ZC%/SL-2Pitch (SX) and Ya w (Se)Canponent Uind Shears atLaunch Tim e of SA-206/SL-2Relative Deviation of Tern -perature and Pressure fnnthe PRA-63 ReferenceAtmosphere. SA-206/SL-2Relative Deviation of Oensftyand Absolute Ceviation of theIndex of Refraction fm ttt ePRA-63 Reference Atmosphe re.SA-206/51-ZSL-2 Space VehicleS-18 Stage ConfiguratfonS-W Stage StructureS-IV6 Stage Configurrtlonlnstrwent Unit ConflguratlonApollo Spacecraft

Page15-815-915-11

A-2

A-4

A-7

A-R

A-9

A-10

A-11

A-13

A-11

B-28-38-b8-88-11B-14

vi i


10/230

LIST OF TABLES

Table Page Table

22-12-27-3

3-l4-lb-21-3b-44-5

b-6b-7

5-l6-l6-2

6-3C-4v-1

7-27-39-1

9-29-3

Mission ObjectiveAccomplishmentSumnay of Failures and AnomaliesTime Base SunnarySignificant Event limes SunnaryVariable Tim e and CarnnandedSwitch Selector EventsSk-206/SL-2 Prelaw.ch Milestoneslunnary of Available Trac kingDataComparison o' Cutoff EventsComoarison of Significan tTrajectory EventsComparison of Separation EventsCarnparison of S-18 SpentStage ImpactS-IB Spent Stage Im pactEnvelopeComoarison of Orbit !nsertionConditionsS-IVB/IU Deorbit VelocityComparisonsS-IB Engine Start CharacteristicsS-IB Individual Engine Pro-pulsion PerformancePropellant Us*)eS-IB Propellant Mass HistoryS-IVB Steady State Perfor-mance (ST DV Open +60 SecondTir rw Slice at Standard AltitudeConditions)S-IVB Stage Propllant MassHistoryS-IVB APS Propellant CoosqtionInertial P latfom VelocityComparisons

Navigation Position and VelocityCaprrisons (PACSS-13)SA-206 Guidance Tem inalConditions

9-4IO-1

2-22-32-10

10-210-3

3-24-2 11-l

11-25-6J-61-74-9

11-315-115-2

4-g 15-315-4

4-B-I

5-l6-76-56-96-117-5

15-s16-116-216-316-416-516-6A-lA-2

7-6 A-3

7-139-3

9-49-5

A-l

A-5

Orbital Phase Flight Pmg rnSteering CmandsWsalignment and Liftoff Condi-tions SunmnayMarirmnn Control ParetersDuring S-IB BumPwinun Control ParametcmDurino C-IVB BumS-IB Staqe Battep ParerConsunntionS-IVB Stage Battery PowerConsumptionIU Battery ?ower ConsuaptionSA-206 Beasum mant SlnnrrySA-206 Fligh t MeasuwaentsWaived Pr'or to Fligh tSA-206 !+easurement MalfunctionsSA-2D6 Launch Vehicle Tel -tryLinis Perfanance SuenarySC-2% IU ConvvandsVenicle Masses (Kilogras)Vehic!e gasses (Pounds)Vehicle Masses (Kilo grms)Vehicle Masses (Pounds)Flight Sequence Mass SmryMass Characteristics ComparisonSurface Obser ations at SA-206Launch TimeSystems Used to Measure Upper AirHind Oata for SA-206Maxim Uind Speed in HighDynrnic Pressure Region forApollo/Saturn 201 throughSaturn 206 VehiclesE~ tm Uind Shear Values Inthe High Dynamic PnssumRegion for Apollo/Saturn 201thrw gh 206 VehiclesSelected A-spheric Obscna timsfor Apollo/Saturn 201 throtqhSaturn 206 Vehicle launches atKennedy Space Center, Florida

PICJC9-9IO-1

10-710-1011-l11-7

11-1115-215-215-215-315-1316-316-316-416-416-S16-7

A-3A-5A-12

A-12

A-16

viii


11/230

LIST OF TABLES (CONTINUED)

Table PeqcB-1 Smnrry af SIB Stage Data D-S8-2 fipn*ficant S-HI Stage B-7

Configuration ChangerE-3 S-M Slaniftcant Confiquration B-10Changes0-4 IU Significant Configuration E-12Changes

ix/x


12/230

ACKNOWLEDGEMENT

This report is published by the Saturn Flight Evaluation Working Group,composed of representatives of Marshall Space Flight Center, KennedySpace Center, and MSFC's prime contractors, and in cooperation withthe Johnson Space Center. Significant contributions to the evaluationhave been made by:George C. Marshall Space Flight Center

Science and EngineeringAero-Astrodynamics LaboratoryAstrionics LaboratoryComputation LaboratoryAstronautics Laboratory

Saturn Program OfficeJohn F. Kennedy Space CenterLyndon B. Johnson Space CenterChrysler Corporation Space DivisionMcDonnell Douglas Astronautics CompanyInternational Business Machines CorporationRockwell Intemational/Rocketdyne DivisionGeneral Electric CanpanyThe 8oeing Company

xi xii/


13/230

ABBREVIATIONS

AOSAPSARIA

BDACDDTCGCIF

CMCNVCR0CRPCSMCYIDEEEBWEC0ECS

EDSEDTEMRESCESE

Acquisition of SignalAuxiliary Propulsion SystemApollo Range InstrumentedAircraftBermudaCountdown Demonstration TestCenter of GravityCentral InstrumentationFacilityCormnand ModuleCape KennedyCamarvonComputer Reset PulseCommand and Service ModuleCanary IslandDigital Events EvaluatorExplosive Bridge WireEngine CutoffEnvironmental ControlSystemEnrergency Detection SystemEastern Daylight TimeEngine Mixture RatioEngine Start CommandElectrical Support Equipment

xiii

FCCFMFRTGBIGBS

GCSGDSGFCVGN2GRRGSCUGSEHAWHEHSKIBMICDIECOIGMIUJSCKSCKUJ

Flight Control ComputerFrequency ModulationFlight Readiness TestGrand Bahama IslandGas Bearing SystemGuidance Cutoff SignalGoldstoneGOX Flow Control ValveGaseous NitrogenGuidance Reference ReleaseGround Support Cooling UnitGround Support EquipmentHawaiiHeliumHoneysuckleInternational BusinessMachinesInterface Control DocumentInboard Engine CutoffIterative Guidance ModeInstrument UnitJohnson Space CenterKennedy Space CenterKwajalein


14/230

LH2LOSLOXLUTLVLVDALVDC

LVGSE

MADMAPWC-H

MDAC

WVMILAMLMOVMRMRCVMSFCMSSMUX

ABBREVIATIONS

Liquid HydrogenLoss of Sign91Liquid OxygenLaunch Utiilical TowerLaunch VehicleLaunch Vehicle Data Adapterlaunch Vehicle DigitalComputerLaunch Vehicle GroundSupport EquipmentMadridMessage Acceptance PulseMission Control Center -HoustonMcDonnell DouglasAstronautics CompanyMain Fuel ValveMerritt Island Launch AreaMobile LauncherMain Oxidizer ValveMixture RatioMixture Ratio Control ValveMarshall Space Flight CenterMobile Service StructureMultiplexer

(CONTINUED)

NFLNPSPNPVOATOECOOMPTOT04s

PACSS

PAFBPCMPEAPLAST

PSDPTCS

PURCARFRLHVASACS

NewfoundlandNet Positive Suction PressureNon-Propulsive VentOverall TestOutboard Engine CutoffObserved Mass Point TrajectoryOperational TrajectoryOrbital Workshop (ModifiedS-IVB Stage)Project Apollo CoordinateSystem StandardPatrick Air Force BasePulse Code ModulationPlatform Electronics AssemblyPropellant Load and All SystemTestPower Spectral DensityPropellant Tanking ComputerSystemPropellant UtilizationRadio Corporation of AmericaRadio FrequencyRetrogrdde Local HorizontalService ArmService Arm Control Switches

xiv


15/230

ABBPEVIATIONS (CONTINUED)

S&S Solar Array SystemSCSDFSLSLA

SpacecraftSystem Development Facil itySkylabSpacecraft Lunar ModuleAdsoter

SM Service Modulesox Solid OxygenSRSCS Secure Range Safety CommandSystemSTDV Start Tank Discharge Valvesvsws

Space VehicleSaturn Workshop

TANTBTCC

TananariveTime BaseThermal Control Coating

TCSTEXTMTVCus

Terminal Countdown SequencerCorpus ChristiTelemetryThrust Vector ControlUnited States

LITVABVHFWLP

Universal TimeVertical Assembly Build ingVery High Frequency (30-300 MHZ)Wallops Island

xv xvi/


16/230

MISSION PLAN

The Saturn IB SA-206 (SL-2 Launch) is to place the Command ServiceModule (CSM-116) in a 150 x 346 km (81 x 187 n. mi.) orbit. SA-206 iscomprised of the S-18-6, S-IVB-206, and the Instrument Unit (IU)-206.This is the first manned flight in the Skylab Program.Launch is scheduled to occur on the 25th of May 1973 from Launch Com-plex 39, Pad B of the Kennedy Space Center (KSC) at 9:00 a.m., EDT.Flight will be along a launch-time-dependent azimuth within a flightazimuth range of 51.7 degrees to 37.8 degrees measured east of north.The launch window duration is 15.5 minutes. Vehicle weight at ignitionis nominally 592,888 kg (1,307,095 lbm).S-IB stage powered flight lasts approximately 141 seconds. The S-IVBstage provides powered flight fDr approximately 436.3 seconds insertingthe CSM into its planned orbit. The CSM Service Propulsion System andReaction Control System will be used to complete the CSM rendezvousmaneuvers and dock axially with the orbiting Saturn Work Shop. In thesame time frame the S-IVB/IU will be maneuvered to, and maintained in,an attitude for conducting the M-415 Thermal Control Coating experiment.Deorbit of the S-IVB/IU will commence on the fourth revolution with thespent vehicle oriented in a retrograde attitude. Residual propellantsin the S-IVB stage tanks will be dumped through the J-2 engine to producethe impulse required for deorbit. By controlling the vehicle attitudeand the time and duration of propellant dump the spent vehicle is directedtowards a designated impact region. Impact is planned to occur in anisland-free area of the Pacific Ocean approximately 6 hours after liftoff.

xvii


17/230

FLIGHT SUMMARY

The Saturn Space Vehicle, SA-206, was launched on May 25, 1973, from KennedySpace Center. The SA-2G6 vehicle supported the Skylab mission by placinga Comnand Service Module containing three crew members into an earth orbitfor rendezvous with the orbiting Saturn Work Shop.The performance of ground systems supporting countdown and launch wassatisfactory except for one anomaly. This anomaly occurred after launchcolrmit and could have transferred vehicle power from internal to externalresulting in launch without vehicle electrical power. The erroneous cutoffsignal, however, was not sustained long enough to energize the cutoff relay.The space vehicle was launched at 9:Or):OO Eastern Daylight Time (EDT) onMay 25, 1973, from Pad 39B of tne Kennedy Space Center, Saturn Complex.The countdown was scrubbed from the original %y 15, 1973 launch date toaccommodate Skylab-l Orbital Work Shop pranlem resolutions and work-arounds(refer to MPR-SAT-FE-73-4 for SA-513/Skylab-1 Flight Report). Damage tothe pad, Launch Umbilical Tmer (LUT) and support equipment was consideredminimal.SA-206 was launched as planned on an azimuth of 90 degrees east of north.A roll maneuver was initiated at approximately 10 seconds that placed thevehicle on a flight azimuth of 47.580 degrees east of north. The downrange pitch program was also initiated at this time. The reconstructedtrajectory was generated by merging the ascent phase and the parking orbitphase. Available C-Band radar and Unified S-Band tracking data, togetherwith telemetered guidance velocity data were used in the trajectory recon-struction. The reconstructed flight trajectory (actual) was very close tothe Post-Launch Predicted Operational Trajectory (nominal). The S-IBstage Outboard Engine Cutoff (OECO) was 1.36 seconds later than nominal.The total space-fixed velocity at this time was 7.07 m/s greater thannominal. After separation, the S-IB stage continued on a ballistic tra-jectory to earth impact. The S-IVB burn terminated with guidance cutoffsignal and parking orbit insertion; both approximately 3.7 seconds laterthan nominal. A velocity of 1.82 m/s greater than nominal at insertionresulted in an apogee 6.32 km higher than nominal. The parking orbitportion of the trajectory from insertion to CSM/S-IVB separation wasclose to nominal. However, separation of the CSM from the S-IVB stageoccurred 17.6 seconds later than nominal, which is not consideredsignificant because it is an astronaut initiated event.

xviii


18/230

All aspects of the S-IVB/IU deorbit were accomplished successfully. Thedeorbit trajectory altitude was slightly higher than the real time pre-dicated value resulting iu an impact slightly downrange of nominal.These dispersions were small enough that impact actually did occur withinthe real time predicted footprint. Impact occurred at approximately21,607 seconds.The S-IB stage propulsion system performed satisfactorily throughoutflight. Stage longitudinal site thrust and specific impulse averaged1.04 percent and 0.3 percent lower than predicted, respectively. StageLOX, fuel and total propellant flowrate averaged 0.78 percent, 0.70percent, and 0.76 percent lower than predicted, respectively. IECOoccurred 0.75 seconds later than predicted. OECO was initiated 3.69seconds after IECO by the deactuation of the thrust OK pressure switches,as planned, of Engine #l. At OECO, the LOX residual was 2916 lbm comparedto the predicted 3297 lbm and fuel residual was 6127 lbm compared to thepredicted 5986 lbm. The S-IB stage hydraulic system performed satisfactorily.The S-IVB propulsion system performed satisfactorily throughout the opera-tional phase of burn and had normal start and cutoff transients. S-IVBburn time was 440.4 seconds, 2.5 seconds longer than predicted for theactual flight azimuth of 47.6 degrees. This difference is composed of-0.15 seconds due to higher than expected S-IB/S-IVB separation velocityand +2.65 seconds due to lower than predicted S-IVB performance. Theengine performance during burn, as determined from standard altitudereconstruction analysis, deviated from the predicted Start Tank DischargeValve (STDV) open +60 second time slice by -0.64 percent for thrust and+0.05 percent for specific impulse. The S-IVB stage Engine Cutoff (ECO)was initiated by the Launch Vehicle Digital Computer (LVDC) at 586.3seconds. The S-IVB residuals at engine cutoff were near nominal. Thebest estimate of the engine cutoff residuals is 2873 lbm for LOX and2223 lbm for LH2 as compared to the predicted values of 3314 lbm for LOXand 2046 lbm for LH2. Subsequent to burn, the stage propellant tankswere vented satisfactorily. The impulse derived from the LOX and fueldumps was sufficient to satisfactorily deorbit the S-IVB/IU. The totalimpulse provided was 88,360 lbf-set with a LOX dump impulse contributionof 75,610 lbf-set and a fuel dump impulse contribution of 12,750 lbf-sec.A disturbing force on the S-IVB/IU, coincident with LOX tank venting inT5 (following propellant dumps), caused unplanned firings of AuxiliaryPropulsion System (APS) module engines and subsequent propellant deple-tion in APS Module No. 2. Analysis indicates nearly complete blockageof LOX Nonpropulsive Vent (NPV) Nozzle No. 1. The blockage has beenattributed to solid oxygen formation at the nozzle inlet during T4 cylicLOX relief venting when liquid remaining in the duct was subjected to afreezing environment. t!o impact due to this anomaly is expected on theSkylab-3 or Skylab-4. Propellant tank safing after fuel dump was satis-factory. The APS operation was nominal throughout flight. No helium

xix


19/230

or propellant leaks were observed and the regulators functioned nominally.Hydraulic system performance was nominal throughout powered flight, orbitalcoast, and deorbit.The structural loads experienced during the flighi were well below designvalues. The maximum bending moment was 14.8 x 10 in-lbf (approximately 27percent of design) at vehicle station 942. Thrust cutoff transientsexperienced by SA-206 were similar to those of previous flights. The maxi-mum longitudinal dynamic responses measured in the IU were 9.20 g and+D.30 g at S-IB IECO and OECO, respectively. POGO did not occur. TheMaximum ground wind experienced by the Saturn IB SA-206 during the prelaunchperiod was 22 knots (55 knots, allowable with damper). The ground winds atlaunch were 12 knots from the Southwest (34 knots allowable).The Stabilized Platform and the Guidance Computer successfully supportedthe accomplishment of the mission objectives. Targeted conditions at orbitinsertion were attained with insignificant error. The one anomaly whichoccurred in the guidance and navigation system was a large change in thegyro sumnation current and a small change in the accelerometer sumnationcurrent in the ST-124N Platform Electronics Assembly. Operation of theST-124M subsystem was not affected by these current changes. There \ras apitch axis gimbal resolver switchover accomplished at 20,558 seconds,following completion of propellant dumps. However, this switchover wascaused by a loss of attitude control when the S-IVB APS propellantsdepleted.The control and separation systems functioned correctly throughout thepowered and coast flight. Control was terminated earlier than predictedduring deorbit by the depletion of S-IVB APS Module 2 propellants. Enginegimbal deflections were nominal and APS firings predictable. Bending andslosh dynamics were adequately stabilized. r!o undue dynamics accompaniedany separation.The electrical systems and Eme;-gency Detection System (EDS) performedsatisfactorily during the flight. Battery performance (including voltages,currents, and temperatures) was satisfactory and remained within acceptablelimits. Operation of all power supplies, inverters, Exploding Bridge Wire(EBw) firing units, and switc!l selectors were nominal.Base pressure data obtained from SA-206 have oeen conpared with preflightpredictions and/or previous flight data and show good agreement. Basedrag coefficients were also calcclated using the measured pressures andactual flight trajectory parameters.Comparisons of SA-206 base region thermal data with corresponding data fromSA-203, SA-204 and SA. 105 show generally good agreement with slightdifferences being att.ibuted to the H-l engine uprating on the SA-206vehicle. Measured heating rates in the base region were all below the S-IBstage design level.

xx


20/230

The S-13 stage engine compartment and instrument compartment requireenvironmental control during prelaunch operations, but are not activelycontrolled during S-IB boost. The desired temperatures were maintainedat both areas during the prelaunch operations. The IU stage Environ-mental Control System (ECS) exhihited satisfactory performance for theduration of the IU mission. Coolant temperatures, pressures, and flow-rates were continuously maintained within the required ranges anddesign limits.Total vehicle mass, determined from post-flight analysis, was within1.15 percent of predicted from ground ignition through S-IVB stagecutoff signal with the exception of a longer than predicted S-W stageburn, resulting in a less than expected residual. Hardware weights,propellant loads and propellant utilization were close to predictedvalues during flight.All data systems performed satisfactorily with theexception of the IUtelemetry system during orbital operation. Flight measurements fromonboard telemetry were 100 percent reliable.Telemetry performance was normal except for a momentary loss of snychroni-zation of the S-16 telemetry signal at liftoff due to burst of electricalnoise. A reduction in Radio Frequency (RF) radiated pcmer from the IUtelemetry links was experienced during the first orbital revolution. Theusual interference due to flame effects and staging were experienced.Usable telemetry data were received until 20,800 seconds (05:43:48).Good tracking data were received from the C-Band radar, with Kwajalein(KUJ) indicating final Loss of Signal (LOX) at 21,475 seconds (5:57:55).Skylab Experiment M-415, a MSFC Thermal Control Coating experiment wasperformed during the flight of SA-206. The object of the experiment wasto determine the effects of preflight and flight environments on variousthermal control coatings. The experiment contained 48 coatings that wereuncovered and exposed to the environment at different times. Preliminarydata indicates that:a.b.C.

d.

All 24 coatings were uncovered as planned.Temperature measurements were received as planned.Coatings which were exposed continuously from prelaunch exhibitedno significant difference in absorptivity/emissivity (a/e) ortemperature.Two of the three coatings sealed until first stage separation asplanned, but exposed to retro motor plumes, indicated approximatelythe same a/e and temperatures but the third sample operated about9C cooler.

xxi


21/230

e. At orbital insertion, all coatings which were exposed continuouslyfrom orelaunch were running 8 to 10C hotter than the coatings whichwere sealed but exposed just prior to the retro motor firing.

xxii


22/230

MISSION OBJECTIVES ACCOMPLISHMENT

Table 1 presents the MSFC launch vehicle objectives for Skylab-2 asdefined in the "Saturn Mission Implementation Plan SL-2/SA-206,"MSFC Document PM-SAT-8010.22, Revision C, dated March 30, 1973, andupdated by MSFC letter SAT-MGR (SAT-E-171-73) dated June 1, 1973.An assessment of the degree of accomplishment can be found in othersecticns of this report as shown in Table 1,

NO.1

Table 1. Mission Obj ective Accomplishment

LAUNCH VEHICLE OBJECTIVELaunch and insert a mannedCSM into the earth orbittargeted for during thefinal launch countdown.SL-2 was targeted foran 81 x 187 n mi.(150 x 346 KM) orbitduring final launchcountdcnvn.

DEGREEOFACCOM-PLISHMENT--Complete

xxiii/xxiv

OISCRE-PANCIESNone


23/230

FAILURES AND ANDMALIES

Evaluation of the launch vehicle and launch vehicle ground support equip-ment data revealed the following four anomalies, one of which is consideredsignificant.

Table 2. Sumnary of Failures and Anomalies

NM. AllllM COltKA NO T KOUlllcOAttfR iEO981t Ovp. (APO 19Ch%WLI. APPD 4 ICC 41

CORKCIIVI ACTIONrOD,FItO SAG'07 ISt IO:I. INnlBll ltW51 FAIlLIlt

CUmFF CIRCUIT Awl)LAmcn mml.

2. PAfv fYt WtrrLC PM@ m m !Ffl ftW INiClllU T O1KtE811 AFlCl CO III T WI1ISSWNM OF tNGllC CUtOFFCOIU IO.

VISW IISPcCrIR OF lwf-nccmLcrcwr K ID QP lK fmmOF 1WSf FOUID OtfCRM.

*Irt.

5

t

i-

i

L

15.3.215.6

7.10.210. J.3

Fi T

xxv/xxvi


24/230

SECTION 1INTRODUCTION

1.1 PURPCSEThis report provides the National Aeronautics and Space Administration(NASA) Headquarters, and other interested agencies, with the launchvehicle evaluation results of the SA-206 flight (Skylab-2 Launch). Thebasic objective of flight evaluation is to acquire, reduce, analyze,evaluate and report on flight data to the extent required to assurefuture mission success and vehicle reliability. To accomplish thisobjective, actual flight problems are identified, their causes deter-mined, and recormnendations made for appropriate corrective action.i.2 SCOPEThis report contains the performance evaluation of the major launch vehiclesystems with special emphasis on problems.and spacecraft performance are included. Sumnaries of launch operations

The official George C. Marshall Space Flight Center (MSFC) position atthis time is represented by this report. It will not be followed by asimilar report unless continued analysis or new information should provethe conclusions presented herein to be significantly incorrect.1.3 PERFORMANCE PREDICTIONS BASELTNEUnless otherwise noted, all performance predictions quoted herein forcomparison purposes are those used in or generated by the SA-206 PostLaunch Predicted Operational Trajectory.

l-1/1-2


25/230

SECTION 2EVENT TIMES

2.1 SUMMARY OF EVENTSRange zero occurred at 09:OO:OO Eastern Daylight Time (EDT) (13:00:00Universal Time [UT]) May 25, 1973. Range time is the elapsed time fromrange zero, which, by definition, is the nearest whole second prior toliftoff signal, and is the time used throughout this report unlessotherwise noted. Time from base time is the elapsed time from thestart of the indicated time base. Table 2-l presents the time basesused in the flight sequence program.The start of Time Bases TO and TT were nominal. T2, T3 and T4 wereinitiated approximately 0.8 seconds, 1.4 seconds and 3.7 seconds late,respectively. These variations are discussed in Sections 6 and 7 ofthis document. Start of T5 was initiated by the receipt of a groundcommand, 193.4 seconds earlier than scheduled as discussed in Section5.2.Figure 2-l shows the difference between telemetry signal receipt at aqround station and vehicle [Launch Vehicle Diqital Computer (LVDC) clock]time. This difference between ground and vehicle time is a function ofLVDC clock speed.A summary of significant event times for SA-ED6 is given in Table 2-2.The preflight predicted times were adjusted to match the actual firstmotion time. The predicted times for establishing actual minus pre-dicted times in Table 2-2 were taken from 68MOOOOlB, "Interface ControlDocument Definition of Saturn SA-206 and Subs Flight Sequence Program"and from the Skylab-2 (SA-206) Post-Launch Predicted Operational Tra-jectory (OT) S&E-AERO-MFP-85-73, dated June 12, 1973.2.2 VARIABLE TIME AND COMMANDED SWITCH SELECTOR EVENTSTable 2-3 lists the switch selector events which were issued during theflight, but were not proqramned for specific times.

2-l


26/230

Table 2-l. Time Base Summary

rIHE BASEI RANGE TIMESECONDS10 -16.95TI 0.53Tz 135.68!3 142.26T4 586.44T5 19.426.79SIGNAL START

Guidance Reference ReleaseIU lhbllical Disconnect Sensedby LVDCS-IB Lou level Sensors DrySensed by LVDCS-IB OECO Sensed by LVDCS-IVB EC0 (Veloci ty) Sensed byLVDCInitiated by Receipt of GroundCmnand

0 10.000 lS.tlOORANGE TIME. SE0011M

8 1 I I I 1 I0 l:oo:oo 2:oo:oo 3:oo:oo 4:oo:oo 5:uJ:oo 6:00:00RMGE TIME, tKHJRS:IIINUTES:SEUMIS

8 RANGE TIME OF CROWD RECEiPT OF TELEMETERED SIGNAL FROM VEHICLEl * RANGE TIME OF OCCURRENCEAS INDICATED BV LWCORRECTED VDC CLOCK

Figure 2-1. LVDC Clock/Ground Time Difference

2-2


27/230

Table 2-2. Significant Event Times SummaryRANGE 1lME TIM E FRCIM R4SE

I TiY FVEMT IWSCRIPT ION ACTUAL ACT-PREP ACTUAL AC f-PR E9SEC SEC SFC SEC

1 .uIOAIUCE RkFERENCE RElE4tF -17.0 0.0 -17.5 -0.1fCRRl

2 S- IR ENGINE STA RT CcTMMAND -3.1 0.0 -3.6 -0.13 .+I9 STA RT SIGNAL ENGINE NO. 7 -3.0 0.0 -3.5 -0.1

4 S-1R STA RT SIGNAL ENGINE NO. 5 -3.0 0.0 -3.5 -0.15 S-IF3 ST4 RT SIGNAL ENGINE NO. 6 -2.9 0.0 -3.4 -0.1b S-1R ST4 RT SIGNAL ENGINE NO. 9 -2.9 0.0 -3.4 -0.17 S-14 Sl4RT SIGNAL EfdClNE NO. 2 -2. R 0.0 -3.3 -0. i8

IS-1R STA RT SIGNAL ENGINE ~JO. 4 -2. R 0.0 -3.3 -0.1

9 S-1R STA RT SIGNAL ENGINE NO. 3 -2. 7 0.0 -3.2 -0.110 S-lfl STA RT SIGNAL ENGINE NO. 1 I-2.1 0.0 - 3. 2 -0. 111 R4NGE ZERn 0.0 0.3 -095 3.212 FIRS T WTION 0.2 0.0 -0.3 -0.113 IV U4BILltA.L DISCONNECT. STA RT 0.5 0.1 0.0 0.0

tlF TIME BASE 1 IllI LIFTOFF14 51 NGLE ENGINE CUT OFF FNARLE 3.5 0.1 3.0 0.015 Lc)X TAN K PRESS URIZATlON 6.5 0. 1 6. 0 0.0

SHUTOFF VALVES CLnSElb BEGIN PITCH ANO uaL MANEUVER 10.0 -0.4 Q. 5 -0.5I7 Wl..IPLE FNGINE CuTn FF ENABLE LO. 5 0.1 I 0.0 0.0

18 Wu:;IPLE ENGINE CUT nFF ENABLE 10.6 0.1 10.1 0.0

19 TELEWFTER CALIBRAlE ON 20. 5 0.1 20.0 0.020 TFLEWTE R CALIBRATE OFF 25.5 0.1 - 25.0 0.021 TELEu ETRY CALIBR4TOR IN-FL tGh T 26.5 -0.9 26.0 -1.0

C4L IBRATE ON22 1ELEMElRr CAllBRAtOA IN-FLIGCf 31.5 -0.9 31.0 -1.0

C4L IBRATE OFF23 LAUNCH VFHICLE ENGINES EOS 39.5 -0.9 39.0 -1.0

CurOFF FNAlLE24 END ROLL NANWVER 54. I3 4.0 563 3.9

2-3


28/230

Table 2-2. Significant Event Times Summary (Continued)

y--$yr:b -A XIYu OVNAPIC PRrSSuRE

!77 TCIEM FTRV CAltRRAlOR IN-FLICUCALl?kATE ONZA iTElE*F7RV CALIRPA:OR :*-;-FL 1C.H

CAl!hAfE OFF49 L IGt iT CINTPOL COMPllTER t*ITCl

YIIV T WI. 1

11 :fLErE TEQ CALlSRATION ON32 FLIGHT CONTROL COWPIJTER SbITCI

?UlNT NO. 333 II ! COVTROL ACCEL. PYR OFF34 TfLEMEfEF CALlF!RATlflN OFF35 TELFfT EFl CALIRRATE ON36 EXCESS RATE (P.V.RJ AUTO-ABO R

INI~ISIT ENA8LE37 EXCESS RAlE (P,V,Rt AUTO-ABO R

IN~IRIf ANO WITCH RATECVSCS SC INOI CATl OY A

3R TFLEVETER CALIARATE OFF39 k-19 Tuf l ENGINES OU T AUTCJ-

AR?RT INHI BIT ENABLE40 S-IB TuO ENGINES OUT AUTO-

ABORT INHIRIT41 PROPELLA T LFVEL SENSORS

ENARLE42 TI LT ARREST43 S-lb PROPE LLANT LEVEL SENSOR

ACT [VAT ION44 STAR T OF TIME BASE 2 (T2l45 ENCESS RATE IROLL) AUTO -ABOR T

tNHI R,lT EYIGC E

TtIPAR E TlMF

ACTUAL ACT -PREOWC fFC60.5 1.575.5 1.090.795.790.5

100.7120.3120.5

t20.7125.3128.01re. 1

120.3

129.0129.6

129.8

130.0

132.0135.7

135.7135.8

0.1

0.1

-0.9

0.1

0.10.1

0.10.10.1

-1.0

-1.0

0.10.1

0.1

0.1

&aO.e

0.80.7

TIMEACTUALSEC

60.075.090.295.299.0

100.2

119.0170.0

170.2124. e121.5127.6

121.8

128.5129.1

129.3

129.5

131.5135.2

0.00.2

SfC .41. P

0. 0

0.0

-1.0

0.0

0.00.0

0.00.00.0

-1.1

-1.1

0.00.0

0.0

3.0

0.50.7

0.00.0

2-4


29/230

Table i-2. Significant Event Times Summary (Continued)

ITEM EVFNT OESCR IPT ION

46 F-XCFSS Q4T E (ROLL 1 AUTO-ABORTINHlRll AND SWITCH RATEGYRO S SC 1NOICAlII)N B

~7 lNBO4RD ENGINES CUT OFFI IECOI*B AUTO-4R ORT ENARLF RELAY, RESE49 CtARGE ULlACE IGN ITIO N EBW

FIRING (INITS50 PRCVALVES t7PEN51 -OX 0:PLETION CUTOFF EN4BlE52 FIJEC DEPLETION CUTO FF ENABLE53 S-16 OVTRCARC ENGINES CUTO FF

fflECOl5s ST4RT OF TIME BASE 3 (f3155 S-19 WTADARC ENGINES CUTO FF56 LOX TAhiK PRESSSURILATION

SHUTOFF VALVES OPEN

57 LOX TANK FLIG HT PRESSURESVSTEY ON58 S-Iv6 ENGINE CUTO FF NO. 1 OFF59 S-Iv8 ENGINE CUTO FF NO. 2 OFF60 SFNSOR PANEL NO 1 AND PANEL 2

COVER NO. 4 EXPULSION61 SENSOR PANEL NO 1 AN0 PANEL 2

COVER NO 4 EXPULSION RES ET62 YIXTURE RATIO CONTROL VALVE

OPEN63 MIXTURE RAT IO CONTROL VALVE

BACKUP OPEN64 JLLAGE RCCKETS IGN ITIO N65 S-18/S-IVB SEPARATION SIGNAL

ON66 S-lB/S-IVB PHVSICAL SEP4RATIO l67 S-IV6 ENGINE IGN ITIO N

SEQUENCE ST& RT CWWAND

T


30/230

Table 2-2. Signi fllant Event Times Summary (Continued)

73


31/230

Table 2-2. Significant Event Times Summary (Continued)RANGE TIME TIME FROM RASFIlFY EVENT DESCRIPTIflN AC WA: ACT-PREn AC TllAL ACT-PR E

SFC SEC SEC SEC03 TFlF*EtRY CALIBRAtClR IN-FLIGHT 352. b 1.3 210.4 0.0CAllHRATE OFF91 IHZ TANK PRESSURfZAtION 445.1 1.3 302.9 0.0CONTROL SYITCII OISABLE92 S- IVR MIXTURE RAt IO CONTROL 470.3 1.3 32 9.1 0.0

VALVt OPEN93 +lXlURF RATIO CCINTRIIL VALV E 410.4 0.0 328. I -0.5OPEN l4.8:1 EMRB94 BEGIN IGP PtiAS E 2 471.R 0.9 329.5 -0.595 PRWELL ANT OEPLE T ION CUTOFF 542. 2 1.3 400.0 0.0ARC96 %FGIN TERrINAL GUIOANCF 564.3 9.9 422.0 8.597 GUIDANCE CUTOFF SIGNAL ICCSl 596.19 3.69 44 3.93 2.3398 S-IV8 SCNENOIO ACTIVAT ION 5Rb. 3 3.8 444.0 4.5SIGNAL99 S-IVB MAINStAGE OK PRESSUR E SOS.4 3.n 444.2 4.6su1tcn 1

100 S-IVR WAINS TACE OK PRESSUR E 596.4 3.8 444.2 4.6SWITCH 2

101 INERTIAL AttItUDE FREEZE 506.4 3.7 0.0 0.0102 St AR1 OF TIME 9ASE 4 (141 596.4 3. T 090 0.0103 f-IV9 ENGINE CUTOFF ND. A ON 596.5 6.3 0.1 0.0104 S-IV8 ENGINE CUtOfF NO. 2 ON 506.6 6.3 0.2 0.0105 PREV ALVE S CLOSE 586.7 3.7 0.3 0.0106 LOX TANK NPV v4LvE WEN ON 591.0 6.3 0. b 0.0101 LOX TAN K PRESSURIL4tION SMUT- 5R?. 2 6.3 0.0 0.0

OFF VALV ES CLOSE ON108 LOX tANK FLIGHT PRES S SVSTE M s97.4 6.3 1.0 Q.0

OFF109 PROPELLA NT DEPLETION CUTOFF 508.2 6.3 1.n 0.0

OISARlr110 S- IVB MIXTURE RATIO CDNTROL S80.6 6.3 2.2 0.0

VALVE CLOSE111 S-IVB MIXTURE RATIO ColvtRDL 5IL 0 6.3 2.4 0.0

VALVE fMCKUP CLOSE

2-7


32/230

Table 2-2. Significant Event Times Summary (Continued)&AWE fl4E TIFF FRO! RASE

I rtr VFhrT IlFXRIPfI~N ACrllAL ACT-PI7 En AC 1llA.L AC T-PmSEC SEC SEC SFC112 FLIGHT CrlNTRCL COMPOTEu s-IV6 599.9 6.3 3.5 0.0Pllkb Wr)CE QFF 'A'113 FL ICHT CONTROL CtlMPlrTER S-Iv6 590.1 6.3 3.7 0.0dW?N WOE IlFF R114 AUX YIDRAULIC PllW P FL ICHf MOCE 590.3 6.3 3.9 0.0rIF F115 S/C CONTROL OF SATURN ENABLE 591.4 6.3 5.0 0.0116 QATE fFASUREMENfS SNITCH 592.4 6.3 690 0.0117 3RRIT INSERTION 596.2 3.1 9. (I -2.6118 S-IV0 ENGINE EDS CUtOFF 596.4 6.3 10.0 0.0DISARLE119 LH2 TANK LATCHING RELIEF VALV E 596. II 6.3 10.4 0.0GPFN ON120 mH2 TANK LAlCtlINC RELIEF VALV E 598.0 6.3 12.4 0.0LalcH ON121 LlI2 TANK LATCHlNC RELIEF VALV E 600.0 6.3 13.6 0.0OPEN OFF122 LM2 TANK LAtCHlNC RELIEF v4LvE 601.2 6-3 14.a 0.0LATCM OFF123 ZHILLOOWY SHUTOFF VAL VES CLOSE 606.4 6*3 20.0 0.0124 PITCH PANEUVE R TO LOCAL nOR 12 607.6 4.9 21.2 1.2125 P.U. INVERTER AND DC P0YER OFF 616.4 6.3 3LO 0.0126 LOX TANK NPV VALV E OPEN OFF 617.0 3.7 30.6 0.0127 LOX TANK VENT AND NPV VALVES 620.0 6.3 33.6 0.0ROOST CLOSE ON128 -OX TANK VENT AND NPV VALVES 622.0 6.3 3S.6 0.0ROOST CLOSE OFF129 _S* SEPARA TION 960.3 17.6 373.9 13.9SLA PANEL JETTISIIN130 PREV ALVES OPEN 1261.3 6.9 680.6 0.6131 Ct4lLLDOwY SHUTOFF VALVE S OPEN 1267.2 6.9 610. B 0.6132 LH2 TANK LATCMIWC RELIEF VALVE 1261.4 699 681.0 0.6OPEN ON133 Ln2 T4NK LATCWtUt RELIEF VILVE 1260.4 6a9 68tO 0.6OPEN OFF

2-8


33/230

Table 2-2. Significant Event Times Summary (Continued)@ANCF TIMF Tt WF FWrlY f$A SFIlt FViNT IWSCRlPTIllN LCTUAl ACT-PREI! AC TIJ AL AC T -P9 ET

---1 ii LH? TAY W VFN T 4N0 LLTCHING 1271.4 6.9 bBS.0 0.6FfLlFF VALVES R@DSf CLOSE ON15 :HZ TAVK VENT 4ND 14TCHlNG RE- 1213.4 6.9 6R?. 0 0.6CIFF VALVES M-JMT CLOSE OFF134 IV IT I ATE fHEUM4L COAT ING 3300. c -32.1 2713.5 -39.5EXPERIwE .c -15137 PA.55 IV AT lflN FN40li 5536. 4 b. 2 5000.0 0.0138 r)CS CII* YIY O EXECUTE LIKIL 7007.0 -5273.2 6420.5 -S219.5

IREFFREhCE MANEUVER

179 DCS OEORB ll COMMLNO 16169.0 -3442.2 1558 1.5 -3449.5140 STA UT OF 1IME RASF 5 (TSl 19426.0 -193.4 0.0 0.0I41 START LOX OWP 19460.0 -194.2 33.2 -0. A142 ENC LOX DUMP 199zo. 9 -193.5 494.1 -0.1143 Sl4UT H2 OUMP 19951.0 -193.2 524.2 0.21** ENC HZ OUPP 2001s. 9 -193.3 649.1 0.1145 S- IVWIu lMP4C T 21607.0 706.0 21020.5 700.5

2-9


34/230

. l

Table 2-3. Variable Time and Carmanded Switch Selector EventsFUNCTION

Telmetry CalibratorIn-Flight Calibrate ONTM Calibrate OR

TM Calibrate OFF

Telemetry CalibratorIn-Flight CalibrateOFFWater Coolant ValveCLOSEDTelemetry CalibratorIn-Flight Calibrate ONTM Calibrate GIN

TM Calibrate OFF

Tel-try CalibratorIn-Flight Calibrate ONTM Calibrate ON

Tl4 Calibrate OFF

Tel-try CalibratorIn-Flight Calibrate OFFTel-try CalibratorIn-Flight Calibrate Cl@!TM Calibrate On

Tn Calibrate GFF

Tel-try CalibratorIn-Flight Calibrafc OFF

STAGE

IUs-Ives-IVBIU

IUIUS-MS-Iv8IUs-mS-Iv6IU

IUS-Iv6s-mIU

RANGETIME(SEC)669.9672.9673.9674.9

780.1

3253.8

3256.8

3257.8

4.933.8

4.936.8

4.937.8

4.938.8

6.173.896.176.8

6.177.8

6.178.8

TIME8::sEc) REMARKS

T4 483.4 NewfoundlandRevolution 1T4 +86.4 NewfoundlandRevolution 1T4 +87.4 NewfoundlandRevolution 1T4 +88.4 Newfoundland

Revolution 1T, +lg3.7 LVDC Function

T4 +2667.2 CamarvonRevolution 1T4 +2670.3 CamarvonRevolution 1T4 +2671.3 Camarvon

Revolution 1T4 +14,347.4 HoneysuckleRevolution 3T4 +14.350.4 HoneysuckleRevolution 3T4 +14,351.4 HoneysuckleRevolution 3T4 +14.352.4 HoneysuckleRevolution 3T4 +15.587.4 HawaiiRevolution 3T4 +15,590.4 HawaiiIWolution 314 +15,591.4 HawaiiRevolution 3T4 +15.592.4 HawaiiRevolution 3

2-10


35/230

SECTION 3LAUNCH OPERATIONS

3.1 SUMMARYThe performance of ground systems supporting the SA-206/Skylab-2 count-down and launch was satisfactory except for the Launch Vehicle GroundSupport Eauipment (LVGSE) cutoff anomaly discussed in Paragraph 3.5.2.This malfunction occurred after launch camnit and could have transferredvehicle power from internal to external resulting in launch withoutvehicle electrical power. The erroneous cutoff signal, however, wasnot sustained long enough to energize the cutoff relay.The space vehicle was launched at 9:00:00 Eastern Daylight Time (EDT)on May 25, 1973, from Pad 39F of the Kennedy Space Center, SaturnComolex. The SA-206/Skylab-2 countdown was scrubbed from the originalMay 15, 1973 launch date to acccmmodate Skylab-l Orbital Work Shopproblem resolutions and work-a :-cunds (refer to MPR-SAT-FE-73-4 forSA-513/Skylab-1 Flight Report). Damage to the pad, Launch UmbilicalTower (LUT) and support equipment was considered minimal.3.2 PRELAUNCH MILESTONESA chronological summary of prelaunch milestones is contained in Table3-l. All stages, S-IB, S-IVB and Instrument Unit (IU) performed satis-factorily and no anomalies were experienced during the countdown.3.3 TERMINAL COUNTDOWNThe SA-206/Skylab-2 terminal countdown was picked up at T-59 hours(countdown clock time) on May 23, 1973. Scheduled holds were initiatedat T-3 hours 30 minutes for a duration of 73 minutes and at T-15minutes for a duration of 2 minutes. The space vehicle was launchedat 9:00:00 EDT on May 25, 1973. Launch cornnit occurred at 0.020 secondsrange time.Postlaunch review of the Digital Events Evaluator (DEE-6) printoutrevealed that at 102 milliseconds after launch cornnit the LVGSE issued amomentary cutoff signal. This signal was present during only one scanof the DEE-6 and was not of sufficient duration to energize the cutoffrelay. This anomaly is discussed in Paragraph 3.5.2.3.4 PROPELLANT LOADING3.4.1 RP-1 LoadingThe RP-7 system successfully supported countdown and launch withoutincident. Tail Service Mast fill and replenish was accomplished at

3-l


36/230

Table 3-l. SA-206/Skylab-2 Prelaunch MilestonesDATE ACTIVITY OR EVENT

August 1, 1972 Command Service Module (CSM) 116 ArrivalAugust 19, 1972 S-IVB-206 Stage ArrivalAugust 22, 1972 S-IB-6 Stage ArrivalAugust 24, 1972 Instrument Unit (IU) S-IU-206 ArrivalAugust 31, 1972 S-IB Erection on Mobile Launcher (ML)-1September 5, 1972 S-IVB ErectionSeptember 7, 1972 IU ErectionOctober 6, 1972 Launch Vehicle (LV) Electrical Systems Test CompleteJanuary 9, 1973 LV Moved to Pad B for First TimeJanuary 30, 1973 Propellant Load and All System Test (PLAST) CompleteFebruary 5, 1973 LV Returned to Vertical Assembly Building (VAB)February 21, 1973 Spacecraft (SC) ErectionFebruary 26, 1973 LV Returned to Pad BMarch 14, 1973 LV Propellant Dispersion/Malfunction Overall Test(OQT)March 29, 1973 Space Vehicle (SV) Electrical MateApril 2, 1973 SV OAT 1 (Plugs In)April 10, 1973 SV Flight Readiness Test (FRT) CompleteApril 23, 1973 RP-1 LoadedMay 3, 1973 Countdown Demonstration Test (CDDT) Completed (wet)May 4, 1973 CDDT Complete (Dry)May 14, 1973 SL-2 ScrubbedMay 23, 1973 SL-2 Scrub Turnaround Preparation StartedMay 25, 1973 SL-2 Launch

3-2


37/230

T-8 hours and level adjust/line inert at about T-60 minutes. Both opera-tions were completed satisfactorily as planned. Launch countdown supportconsumed 41,616 gallons of RP-1.3.4.2 LOX LoadingThe LOX system successfully supported countdown and launch withoutincident. The fil l sequence began with S-IB chilldown at 2145 EDT,May 24, 1973, and was completed 2 hours 3 minutes later with al l stagereplenish at 2348 EDT. Replenish was automatic through the Terminal Count-down Sequencer (TCS) without incident. LOX consumption during launchcountdown was 160,000 gallons.

3.4.3 LH2 LoadingThe LH2 system successfully supported countdown and launch. The fi llsequence began at 2347 EDT, May 24, 1973, and was completed 53 minuteslater when normal S-IVB replenish was established manually at DO40 EDT,May 25, 1973. Replenish was nonina l and was terminated at the startof TCS. Launch countdown support consumed about 150,000 gallons ofLH2.3.5 GROUND SUPPORT EQUIPMENT3.5.1 Ground/Vehicle InterfaceIn general, performance of the ground service systems supporting al l stagesof the launch vehicle was satisfactory. Overall danage to the pad, LUT, andsupport equipment from blast and flame impingement was consideredminimal.The Propellant Tanking Computer Systems (PTCS) adequately supported al lcountdown operations and there was no damage.The Environmental Control System (ECS) perfoned satisfactorily throughoutthe countdown and launch. Changeover from air to GN2 occurred at 2041EDT on May 24, 1973.The Service Arm Control Switches (SACS) satisfactorily supported SL-2launch and countdown. The SAC No. 3 primary switch closed at 289 mill i-seconds and SAC No. 7 primar.y switch closed at 268 milliseconds aftercomni t. There were no problems and only a min imal amount of heat andblast damage to the SACS.The Hydraulic Charging Unit and Service Arms (S/A's lA, 6, 7, and 8)satisfactorily supported the SL-2 countdown and launch. Performance wasnominal during terminal count and liftoff.During CDDT primary damper disconnect from the Spacecraft in support of

3-3


38/230

Mobile Service Structure (MSS) emplacement on May 4, 1973, a hydraulichose ruptured (Retract Damping Cylinder Hose, PN llM00718-13). Thefailed hose was replaced. Subsequently, the primary damper hydraulichoses were proof tested in place to iOO0 psig, and the system was func-tionally tested.Because of this hose rupture during CDDT it was decided that the PrimaryDamper would not be connected during launch countdown unless high windsendangered the launch vehicle. ?rimary damper operation was notrequired. The auxiliary damper performed normally.The DEE-3 and DEE-6 systems satisfactorily supported al? countdownoperation. There was no system damage.3.5.2 MSFC Furnished Ground Support EouipmentAll Ground Power and Battery Equipment supported the prelaunch operationssatisfactorily. All systems performed within acceptable limits. TheHazardous Gas Detection System successfully supported SL-2 countdownon May 24, 1973.Postlaunch revieulr of the DEE-6 print out revealed that at 102 milli-seconds after cornnit, the Saturn IB ESE issued a momentary cutoff signal.This signal was substantiated by the recording of a thrust failureindication and cutoff start indication during one scan of the DEE-6.The cutoff signal was not of sufficient duration to energize the cutoffrelay (K-72). See Figure 3-l.If the erroneous cutoff signal had been sustained long enough toenergize the cutoff relay, an improper automatic cutoff sequence wouldhave been initiated. Vehicle power would have been transferred frominternal to external without engine cutoff resulting in launch withoutvehicle electrical power and mission or vehicle loss (see Figure 3-l).Circuit analysis has revealed the source of these indications to be amomentary re-energization of the Launch Bus (+lD161), caused by remakeof the launch bus contactors. This resulted in a circuit through thethrust failure cutoff circuitry to the cutoff relay (K72) and issuanceto the DEE-6 of a thrust failure and initiation of a cutoff sequence(Figure 3-l). Test results confirmed that the contactor remake resultedfrom diode suppression of the launch bus contactor coils (See Figure 3-2).Diode suppression for these coils was not intentionally provided but wasinherent in the ESE circuitry through a diode in a discrete input signalconditioner of the RCA 1lOA ground computer (see Figure 3-l). Diodesuppression dampens voltage transients, but also extends the inductivetime constant of the collapsing electrical circuit through the contactorcoil. This delays the decay of the coils magnetic force so that as thecontactor's contacts break the magnetic force exceeds the mechanicalspring force which is attempting to open the contacts and causes a manentaryremake.

3-4


39/230

. .

1DlR 1DlP RfTllnk

*1DllO!III IH LSL 6USt - I

(Of-LNERGIZEDAFlfR Ccmll,

SNCAK SucP9f5sIoKDIOJf

PKl 1i'D161 LAUNCN 6US

I6f-fNt66IZf D Afltll CD)rl)

(4) LAW04 6US RtMAKt CIRCUITR T

LAUNCH W5

/

+I0161K94T

IT IA FO R Ccwf ll

I94 v lCLOStD AfftR COmlT) IIfNGlNE 9WNIRGSIGNAL WCU IU

l CuTofr STLRffNDIC11I~lO W-61I (9) nmus~ wLu6f cmorf CIR CUITRY I

S-16 SllpIf GKOUND*PwfP coalccTo9s

l fNfRGlZIN6 Of SIB Slltf GROUND PCUfR COhl4C:WRESWLTS IN PcwfR 1MNSrfs fW Ih lfRWL TCflffRWL on AL1 ST& fS(Ci PWfR TRKf*Sfffi cIRCCI:II'

Figure 3-l. ESE Cutof f Anomaly - Simplified ESE Circuitry


40/230

TIME FROM CONTACTOR DE-ENERGIZATION,ms TIME FROM CONTACTOR DE-ENERGIZATION. ms200

2 100

OFFUPPERTRACE - CONTACTOR URRENTLOWERTRACE - CONTACT STATUSPPERTRACE - CONTACTOROLTAGELOWER RACE - CONTACTSTATUS

(A) CONTACTORWITH OIODE SUPPRESSION ND RESULTINGREMAKE

TIME FROMCONTACTOR E-ENERGIZATION, ms

(9) CONTACTOR ITHOUTDIODE SUPPRESSION ND ABSENCE F REMAKEFigure 3-2. ESE Cutoff Anomaly - Test Results


41/230

~~~ nomallv closed commit (K86) relay contacts shown on the Figure 3-lhave been added to inhibit the thrust failure cutcff circuit aftercofmiit. Additionally, the automated power transfer circuirry has beenmodified to prevent a power transfer to external after cornnit until anactual command to cutoff the S-IB stage engines has been given (seeFigure 3-l). This makes the ESE power transfer logic consistent withthe cutoff logic. These modifications have been verified at the MSFCSaturn IB Systems Development Breadboard Facility and are installed inthe ESE for SA-207. This anomaly is considered closed re lative to thepower transfer circuitry. Additional tests and analysis were conductedtc verify proper operation of all launch vehicle and ESE relay appli-caticns from "time for ignit ion" through the last unbi lical disconnect.

343 -8


42/230

SECTION 4TRAJECTORY

4.1 SUMMARYSA-206 was launched as pl dnned on an azimuth of 9@ degrees east ofnorth. A roll maneuver was init iated at approximately 10 seconds thatplaced the vehicle on a flight azimuth of 47.580 degrees east of north.The down range pitch program was also initiated at this time.The recnnstructed trajectory was generated by merging the ascent phaseand the parking orbit phase. Avai lable C-Band radar and Unified S-Bandtracking data, together with telemetered guidance velocity data were usedin the trajectory reconstruction.The reconstructed flight trajectory (actual) was very close to thePost Launch Predicted Operational Trajectory (nominal). The S-18 stageOutboard Engine Cutoff (OECO) was 1.36 seconds later than nominal . Thetotal space-fixed velocity at this time was 7.07 m/s greater than nominal .After separation, the S-IB stage continued on a ballistic trajectory toearth impact. The S-IVB burn terminated with guidance cutoff signal andparking orbit insertion; both approximately 3.7 seconds later thannominal. A velocity of 1.82 m/s greater than nomina l at insertionresulted in an apogee 6.32 km higher than nominal.The parking orbit portion of the trajectory from insertion to CSM/S-IVBseparation was close to nominal . However, separation of the CSM fromthe S-IVB stage occurred 17.6 seconds later than nominal, which is notconsidered significant because it is an astronaut init iated event.4.2 TRAJECTORY EVALUATION4.2.1 Ascent PhaseThe ascent phase spans the interval from guidance reference release toparking orbit insertion. The ascent trajectory was established from -'telemetered guidance velocity data, the tracking data from five C-Bandstations described in Table 4-1, and an 18 term guidance error model.The ini tia l launch phase (from first motion to 22 seconds) was estab-lished by a least squares curve fit of the ini tia i portion of the ascenttrajectory developed above. Comparisons between the resultant bestestimate trajectory and the avai lable tracking data shows consistencyand good agreement.


43/230

Table 4-l. Sumnary of Available Tracking Data

DATA SOURCE, TYPE PHASEBermuda, C-Band AscentBermuda, C-Band OrbitalBermuda, S-Band OrbitalCape Kennedy, C-Band AscentMerritt Island, C-Band AscentPatrick, C-Band AscentWallops Island, C-Band Ascent/Orbital

INTERVAL(SEC)

295-708258-708400-690

20-42022-50332-504

190-656

Telemetered guidance data were used as a model for obtaining proper-__ . wvelocity and acceleration profiles through the transient areas of MaCII I,maximum dynamic pressure, S-16 thrust decay, and S-IVB thrust decay.Actual and nominal altitude, cross range, and surface range for theboost phase are presented in Figure 4-l. Figure 4-2 presents similarcomparisons of space fixed velocity and flight path angle. Comparisonsof actual and nominal total inertial accelerations are displayed inFigure 4-3. Inspection shows the actual was very close to the nominalvalues.The S-IB stage OECO wa s a result of LOX depletion and the S-IVB GuidanceCutoff Signal (GCS) was issued by the guidance canputcr when end con-ditions were satisfied.The accunul ated difference between actual and nominal .m time of theS-IB and S-.IVB stages was 3.71 seconds. The S-IB s& ,e contributed 1.36seconds of---- -- -. this deviation and the S-IVB bum contributed 2.35 seconds asshown in Table 4-2. Trajectory parameters at significant events arepresented in Table 4-3. Table 4-4 presents significant parameters atthe S-Is/S-IVB and S-IVB/CSM separation events.

4-2


44/230

4-3


45/230

Figure

lO.OOO-

9300=

8000.

3000*

2000.

1000.

O-

4-2. Asce

- ACTUAL--- NOMINALFS-IB IECO36r I I I I

0 100 200 300 400 500 600RANGE TIME. SECONDS

mnt Trajectory Space-Fixed Velocity and Flight Path Angl f3 Comparison


46/230

0-

4-5


47/230

Table 4-2. Comparison of Cutoff Events

I PAlMETERCange :im (set)altitude (km)Space-flwd Velocity (m/s )fl?ght Pdth Angle (deg)Hcddlng Pngle (deq)Surface Ramp (km )Cross Range (km)cross Range Velocty (a/s)

TACTUAl138.7

54.702266.18

26 61555.47359.35

0.541.31

S-18 IECO I S-16 OECOACTUAL142 26

t58.14

2330.3623.95855.23765.71

0.551.09

IdO 90 1.36 586.21 582.5 3.7158.22 -0.06 158.37 158.34 0.03

2323.31 7.07 ?a65.54 7064.87 11.6724.416 -0.458 -0.007 -0.008 0.00155.157 0.080 55.398 55.33C 0.06863.95 1.76 1782.73 1773.27 9.46-0.08 0.63 -33.87 -33.20 -0.67-3.65 4.74 -232.59 -275.a3 3.24

KT-NOM ACTULLT S-IYB GCS

ACT-NO

Table 4-3. Comparison of Significant Trajectory EventsEVEN T PARAMETER ACTUAL NONINAL ACT-NOM

First Motion Range Time , set 0.190 0.190 0.000Total Inertial

Acceleration, m/s2 12.090 12.234 -0.144Mach 1 Range Time , set 60.500 58.973 1.527

Altitude. km 7.66 7.43 0.23Maximwn Dynamic Pressure Range Time , set 75.500 73.583 1.917

Dynamic Pressure, N/an2 3.381 3.361 0.020Altitude, km 12.84 12.43 0.41

Maximum Total InertialAccelera tion: s-IB Range Time , set 138.640 137.902 0.73R

Acceleration, m/s2 44.277 42.906 1.371Maximum Earth-Fixed

Velocity: S-18 Range Time , set 142.000 141.190 0.810Velocity, m/s 2040.94 2037.29 3.65

,Maximum Total InertialAccleration: s-IVB Range Time. set 586.210 582.402 3.808

Acceleration, m/s2 27.982 28.149 -0.167Maximum Earth-Fixed

Velocity: S-IV8 Range Tim, set 591.000 584.190 6.810Velocity, m/s 7570.49 7568.76 1.73

+Ikarest Tim Points Available

4-6


48/230

j *

.

Table 4-4. Comparison of Separation Events

\

S-IBIS-IVB S-IVB/CSMPARAHTER ACTUAL NIMINAL ACT-NU4 ACTUAL NOMINAL ACT -NW

Range fine (set ) 143.7 142.3 1.4 960.28 942.70 17.58Altitude (rm ) 59.34 59.47 -0.13 172.32 171.13 1.19Space-Fixed Velocity (m /s) 2326.16 2323.49 2.67 7859.32 7858.79 0.53Flight Path Angle (deg) 23.680 24.166 -0.486 0.387 0.361 0.026Heading Angle (deg ) 55.244 55.152 0.092 78.840 77.681 1.179Geode tic Latitude (deg ) 29.036 29.031 0.005 49.265 43.068 0.197Longitude (deg ) -80.102 -80.120 0.018 -34.125 -35.615 1.490Surface Range (km ) 67.98 66.26 1.72 me -- __Cross Range (km ) 0.55 -0.09 0.64 _- ma -aCross Range Velocity (a/s) 1.12 -3.60 4.72 -- -- me

.

Mach number and dynamic pressure history comparisons are shown inFigure 4-4. These parameters were calculated using measured meteorolo-gical data to an altitude of 66 km; above this altitude the U. S. StandardReference Atmosphere was used. The variations seen in the actual dynamicpressure near its peak are attributable to the high wind gusts which weremeasured but that did not appear in the monthly average wind used indeveloping the nominal case.A theoretical free flight trajectory was computed for the spent S-IBstage, using initial conditions fKm the actual trajectory at S-IB/S-IVBseparation signal. Three trajectories were integrated from that pointto impact using nominal retro motor performance and outboard enginedecay data. The three trajectories incorporate three different drag condi-tions for 1) stabilized at zero angle of attack (nose forward), 2) tumb-ling stage, and 3) stabilized at 90 degree angle of attack (broadside).Tables 4-5 and 4-6 sumnarire the results of these simulations and presentthe impact envelope. Tracking data were not available, but previousflight data indicate the tumbling drag trajectory to be a close approxi-mation to actual flight. The impact point for this case was 31.547degrees north latitude, 76.756 degrees west longitude.4.2.2 Orbit PhaseThe orbit documented herein originates at orbit insertion and terminatesat S-IVB/CMS separation.

4-7


49/230

DYNAMIC PRESSURE, N/cm2d d h) h) N w. *to w0 CI ;\, b, -0 .P bD .N in. IMACH NUMBER


50/230

Table 4-5. Comparison of S-IB Spent Stage Impact PointPARWETER ACTUAL NOMINAL ACT-NOM

Range Time (set) 535.34 536.76 -1.42Surface Range (km) 493.44 496.83 -3.39Cross Range !km) 4.17 3.07 1.10Geodetic Latitude (deg) 31.547 31.574 -0.027Longitude (deg) -76.756 -76.736 -0.020

NOTE: Data reflects simulation of tumbling stage.

Table 4-6. S-IB Spent Stage Impact Envelope

I DRAG SIMULATIONPARAMETER I NOSE FORWARD I TUMBLING

Range Time (set) 473.76 535.34 576.64Surface Range (km) 506.21 493.44 484.49Cross Range (km) 4.40 4.17 4.03Geodetic Latitude (deg) 31.620 31.547 31.495Longitude (deg) -76.652 -76.756 -76.829

BROADSIDE

Orbital tracking was conducted by the NASA Space Tracking and DataNetwork. One C-Band (Bermuda) and one S-Band station (Bermuda) wereavailable for tracking coverage during the first revolution. Some highspeed tracking data beyond insertion were available from WallopsIsland. These high speed data were edited to provide additional usefulorbital tracking information. The trajectory parameters at orbitalinsertion were established by a differential correction procedure inthe Orbital Correction Program which adjusts the preliminary estimate ofthe insertion conditions to final values in accordance with relative weightassigned to the tracking data. A comparison of the actual and nominalparking orbit insertion parameters are delineated in Table 4-7. Figure4-5 presents the SA-206 ground track from liftoff through CSM separation.

4-9


51/230

Table 4-7. Comparison of Orbit Insertion Conditions

PARAMETER ACTUALRange Time (set) 596.21Altitude (km) 158.52Space-Fixed Velocity (m/s) 7873.35Flight Path Angle (deg) 0.011Heading Angle (deg) 55.855Cross Range (km) -36.56Cross Range Velocity (m/s) -265.81Inclination (deg) 50.030Descending Node (deg) 155.213Eccentricity 0.0152Apogee Altitude (km) 352.07Perigee Altitude (km) 149.99Period (min) 89.53Geodetic Latitude (deg) 39.271Longitude (deg) -65.053

NOMINAL-592.50158.49

7871.530.009

55.785-35.92

-269.0250.032

'55.2220.0148

345.75149.9789.4639.ZLO

-65.141

ACT-NOM3.710.031.820.0020.070

-0.643.21

-0.002-0.009

0.00046.320.020.070.0510.088

4-10


52/230

HIWtv - mnlIlV1

4-11/ 4 -12


53/230

SECTION 5S- IVB/IU DEDRBIT ANALYSIS

5.1 SUMMARYAll aspects of the S-IVB/IU deorbit were accomplished successfully.The deorbit trajectory altitude was slightly higher than the real timepredicted value resulting in an impact slightly downrange of naninal.These dispersions were small enough that impact actually did occurwithin the real time predicted footprint. Impact occurred at appn>xi-mately 21,607 seconds.

5.2 DEORBIT MANEUVERSTimebase 5 (start of S-IVB/IU deorbit events) was initiated 193.5 secondsEarlier than nominal to free communication equipment needed in workingOrbital Worh Shop problems. During the fourth revolution, with the S-IVB/IU oriented in a retrograde attitude, deorbit was initiated with a LOXdunp at approximately 19,460 seconds for a duration of 460 seconds. Thiswas followed 30 seconds later with a schedule LH2 dunp having a durationof 125 seconds. Attitude control was adequately provided by the thrustvector control system of the J-2 engine and the APS during the dumps.T>o velocities for the deorbit sequence are presented in Table 5-l. asreal time predictions, propulsion reconstructions, and the accumulatedtelemetered acceleration data from Apollo Range Instrument Aircraft (ARIA).The data presented show that the total retrograde velocity imparted to theS-IVB/IU was within the real time estimated dispersions, although the velocityfrom the commanded LH2 dunp was outside the real time estimate, see para-graph 7.9.

Table 5-l. S-IWIU Deorbit Velocity Canparisons

LOX .'vWSEC) $E"clReal time Prediction: Marimm 29.73 6.27

Naninal 24.55 5.91Miniman 19.05 5.37

Propulsion Reconstructed 23.03 4.63Telemetered Accelenm wtet Data 23.09 4.01

TOTAL .:v@/SEC)36.0030.4624.42

27.06

27.10

5-l


54/230

5.3 DEDRBIT TRAJECTORY EVALUATIONThe deorbit trajectory reconstruction was based on a tracking vector.The LOX and LH2 dump data used in the reconstruction were taken from thepropulsion parameters.The deorbit trajectory altitude was slightly higher than the real timenominal, as seen in Figure 5-l. This is attributable to the retrogradevelocities being slightly lower than nominal. The accumulated effectwas that the impact occurred siiqhtly downrange of nominal. This wasnoted in real time by the Kwajalein radar which tracked the vehicleafter the deorbit maneuver and provided a positive confirmation ofdeorbit.Attitude control was lost approximately 418 seconds after the LH2 dumpterminated due to deplet ion of APS Module No. 2 propellants (paragraph7.10.2). Though the S-IVB/IU tumbled prior to reentry, this did nothave a significant effect on th? deorbit trajectory or impact location.5.4 IMPACT FOOTPRINTThe actual and real time predicted footprints, includ ing dispersions,are shown in Figure 5-2 for the SA-206 S-IVB/IU impact. Impact occurredin the Pacif ic Ocean at approximately 21,607 seconds, 787 seconds laterthan predicted. The delay and downrange aspect of impact are bothattributable to the less than predicted retrograde velocities acquiredin the scheduled LOX and LH2 dumps. See Paragraph 7.9.

RANGE TIME. tW6Figure 5-l. S-IVB/IU Deorbit Trajectory Alti tude (No Breakup Assumed)

5-2


55/230

c3 c c s-3-


56/230

SECTION 6S-IB PROPULSION

6.1 SUMPlARYYhe S-16 stage propulsion system performed satisfactorily throughoutflight. Stage longitudinal site thrust and specific impulse averagedl.C? percent and 0.3 percent lcwer than predicted, respectively. StageLOX, fuel and total propellant flowrate averaged 0.78 percent, 0.70percent, and G.76 percent lower than predicted, respectively. InboardEngine Cutoff (IECO) occurred 0.76 seconds later than predicted. Out-Loard Engine Cutoff (OECO) was ini tiated 3.68 seconds after IECO by the&actuation of the thrust OK pressure switches, as planned, of Engine tl.At OECO, the LOX residual was 2916 lbm compared to the predicted 3297 lbmand fuel residual was 6127 lbm compared to the predicted 5986 lbm. TheS-IB stage hydraulic system performed satisfactorily.6.2 S-IB IGNIT!ON TRANSIENT PEfiFORllANCEAll eight H-l engines ignited satisfa:torily. The automatic igni tionsequence, which schedules the engines tc start in pairs with a 0.100second delay between each pair, began with igni tion command at -3.055seconds range time. The start sequence that occurred, while not optimum,was satisfactory. The maximum spread in the start times of engines withina pair was 0.037 seconds and was between Engines 2 and 4 (third pair ofengines). The maximum deviation in the planned C.160 second sequencebetween pairs was 0.133 seconds and was tetween the second and thirdpair. The start sequence of eigh t engines in four nairs with 0.100seconds between pairs, while optimum, is not a likely cccurrence. PastS-IB start sequences have al l Leen satisfactory but none exactly optimum.Table 6-l compares predicted and actual start event times. The indiv idualengine thrust bui ldup curves are shown in Figure 6-1. The thrust valuesshown are the total engine thrusts and do not account for cant angles.6.3 S-IB I~AIfiSTAGE PERFORVANCES-IB stage performance bras satisfactory although lower than predicted asshcwn in Figure 6-2. Stage longitudinal site thrust averaged 18,670pounds (1.04 percent) lower than predicted. Stage specific impulseaveraged 0.83 seconds (0.30 percent) lower than predicted. The stagemixture ratio averaged 0.0017 (0.074 percent) lower than predicted.Total propellant flowrate averaged 47.9 lbm/sec (0.76 percent) lowerthan predicted. These averages were taken between range time zero andIECO.

6-l


57/230

Table 6-1. SIB Engine Start CharacteristicsTIME. ENGINE IGNITION

sIW;fe ;f PRIME .IrNGINE POSITIO N TIRf,lGN ITION COMMAND TINE. ENGINE IGNlTlnN

AND SEPIA1 TO ENGINE 11317;ON SIGNAL TO THR USTNUKX G SIGNAL (me t) CHAMBER I( ;NlT?ON. (msec)1 ACTUAL() PROCW+YED ACTUAL NOWINAL

51Ii-406A7 H-40706 H-4069R H-40722 N-70724 H-70751 H-70713 Ii-7n73

105105204204303303

1001002002003co300100

52257257655759239554

ACTbALR57Em2A63R62934U97RanR5400 552

(1) Values referenced to event Tire for- 17lition ~ounanrl.(2) Values presented are mean values


58/230

t

I

-&--- - c__- . . . . -A.--

--I

E_

I!

=I_------- 5

: .---fit@-

::- -4 -_i-1EI

6-3


59/230

S-IB propulsion system flight performance was determined by reconstructingthe flight with the Mark IV computer program: a mathematical model of theSaturn first stage propulsior system which utilizes a table of influencecoefficients to determine engine performance. Input data was obtainedfrom telemetry fiight measurements and calculated propellant residuals.The lower than predicted site thrust and specific impulse were primarilythe result of the engines performing at lower power levels than expectedfor- rated operating conditions, although colder fuel and hotter LOXthan predicted also contributed to the lower site values.Table 6-2 summarizes the S-IB engines propulsion performance, reducedto standard sea level conditions and compared to the predicted performanceand also redaced to standard conditions.Postflight evaluation of previous Saturn IB flights had shown that the200 Klbf thrust enaines exhibited significantly higher (1.0 percent)Lhrust and flowrates at rated conditions than those obtained during singleengine and stage acceptance tests (ground), although the specific impulsewas slightly lower during flight. Therefore, the uprated S-IB-6 engines(205 Klbf thrust) were predicted to have higher sea level thrust valuesthan indicated by the acceptance tests because similar trends wereexpected. However, sea leve l thrust values derived from the S-IB-6flight data, given in Table 6-2, were lower than acceptance test data.Stage static tests for S-18-6 also showed sea level data lower than theEngine Contractor tests.Targeting performance for this stage was complicated due to inconsis-tencies in the different ground tests. Thus, the lower flight performancemay be a result of the same inconsistencies and not the unique flightperformance of 205 Klbf H-l engines.Engine #l gearcase lubricant pressure experienced unexpected inf lightpressure shifts of approximately +8, +13, and -8 psi at 2, 28, and 93seconds range time (Figure 6-3). The fourth step (at 138 seconds) isa normal response to Inboard Engine Cutoff.The first three pressure steps are not completely unusual, the same typehaving been observed during flight on Engine Position 2 of SA-205. Also,at least 14 prior cases of abrupt change in gearcase lubricant pressurehave been observed during static testing at the Engine Contractor site.All such perturbations were determined to have been caused by part ialrestriction of indiv idual bearing jets by particles remaining in the lubesystem passages from the casting process or introduced during turbopumpassembly. Improved procedures for flushing these passages and maintainingthem in a clean condition have been implemented to correct this condition.No etiidence of damage due to jet restriction has been experienced becauseredundancy is provided by multiple lubrication jets in addition to splashlubrication from the gears to the bearings. No corrective action is con-sidered necessary because no evidence of damage has been experienced with

6-4


60/230

:NGINENO.

1

2345670

Ml

Table 6-2. S-IB Individual Engine Propulsion Performance*

PRED206,061

204,186205,554204,539206,334205,533205.552205,236205,374

THRUST(LBF)ACTUAL

202,292

204,233202,720203,897203,781203,908203,839203,828203,563

% OIFF-1.829

to.023-1.315-0.314-1.237-0.791-0.833-0.686-0.881

SPECIFIC Ii lPUSLE(LBF-SECILBY)

LOX FLOWPATE(LBWSEC)PRED 1 ACTUFL

262.901 262.09262.580 261.85262.469 261.55263.005 262.32262.598 262.05

I263.299 262.74263.030 262.52262.794 262.08

1 DIFF PRED-0.341 542.68

t

-0.308 536.09-0.278 542.56-0.350 537.70

ACTUAL534.66

539.16536.74539.24538.55539.45539.02530.47538.15

% DIFF-1.478

to.573-1.073to.271-0.949-0.549-0.586-0.45?-0.534

FUEL FLONRATE(L~M/SEC)PRED

242.39

240.58240.62241.51240.82240.28238.48239.35240.50

l PcrConnancc levels reduced to standard sea level cond itions. Data taken at 30 seconds.Standard sea level conditions:

LOX density (970.79 lbm/ft3)Fuel density (50.45 lbnVft3)Anblent pressure (14.67 psla)Fuel pump Inlet pressure (57.00 psta)LOX pump inlet pressure (6500 psia)Fuel temperature (60.0'F)

ACTUAL Z DIFF238.67 -1.535

240.07 -0.212237.46 -1.313240.33 -0.489238.30 -1.046238.66 -0.674236.79 -0.709237.95 -0.505238.53 -0.819-.

NIXTURE RATIO

PREOT.2380

?.22842.25822.2268r.25772.2576t.27362.25992.2501

O/FACTUAL2.2401

2.24582.26032.24372.25992.26032.2BQ22.26292.2566

Z DIFFto.058to.781to.093to.759to.097to.120to.290to.133to.289

:


61/230


62/230

;tirtially and even completely blocked bearing lube jets. The otherwven r;earcasc lubricant pressures were normal throughout the flight.kithouge contamination in this system is apparently not an unsafecondition. any contamination is a significant concern. The Engine Con-tractor bill review the cleaning, assemtly, and test histories for theengines assigned to the remaining Saturn IB missions to provide assurancethat con:anination will not exceed acceptable levels.6.4 S-18 SHUTMlUH TRAf!SIERT PERFORHARCEThe cutoff sequence on the S-IB-6 stage began at 135.34 seconds withthe actuation of the low-level sensor in LOX tank 02. IECO was initiated3.32 seconds later by the LVDC at 138.66 seconds. IECO was 8.76 secondlater than predicted. The longer than predicted burn time to IECO wasthe result of engine rated power levels lower than predicted, LOX warmerthan predicted, and the fuel colder than predicted.Thrust decay on each inboard engine was normal. The total IECO impulsewas 267,520 lbf-set compared to the predicted impulse of 279,638 lbf-sec.Inboard engine total thrust decay is shown in Figure 6-4.LOX starvation was experienced by the four outboard engines. OECO wasinitiated by deactuation of a thrust OK pressure switch on Engine 1 andOECD occurred at 142.34 seconds. The predicted time differential betweenIECO and OECO was 3.00 seconds. The actual time differential was 3.69seconds. The 0.68 seconds greater IECO-OECO delta time was caused bythe combined effects of (1) early T2-IECO timer, (2) lower LOX flowrate,lower fuel temperature, higher LOX temperature, and less LOX residualthan predicted, (3) greater center-to-outer tank height differential.Thrust decay of each outbcard engine was normal. See Figure 6-5. Totalcutoff impulse for the outboard engines was 184,987 lbf-set, comparedto the predicted impulse of 207,444 lbf-sec.6.5 S-IB STAGE PROPELLANT W~AGEIIEHTPropellant management is the relationship of the propellant consumed topropellant loaded, and is a7 indication of the nropulsion system perfor-mance and the capability of the propellant loading system to load theproper propellant weights. The predicted and actual (reconstructed)percentages of loaded propellants utilized during the flight are shownin Table 6-3.The planned mode of OECO was by LOX starvation to be detected by theengines thrust OK switches. The LOX and fuel level cutoff probeheights and flight sequence settings were determined for a 3.00 secondtime interval between cutoff probe actuaticn and IECO. The plannedtime interttal between IECO and OECO was 3.00 seconds. OECO was to be

6-7


63/230

i3R.0 138.5 139.0 139.5 140.0 140.5 141.0 141.5RAIICE TIME. fEcoNo5

Figure 6-4. S-IB Inboard Engine Total Thrust Decay

142.0 142.s 143.0 143.5 144.0 lU.5 145.0 145.5amIx ll(lE. steams

11

9

6

Figurr 6-5. S-IB Total Out?mard Engine Total Thrust Decay

6-8


64/230

PROPELLANTTotalFuelLOX

Table G-3. S-IB Propellant UsagePREDICTED ("d) ACTUAL (S)

99.20 99.2198.34 98.2699.58 99.64

ini tiated by the deactuation of two of the three thrust OK pressureswitches on any outboard engine as a result of LOX starvation. It wasassumed that approximately 271 gallons of LOX in the outboard suctionlines were usable. The backup timer (flight sequencer) was set toinit iate OECO 13.00 seconds after initiation of T2.To prevent fuel starvation, fuel depletion cutoff probes were locatedin fuel tanks F2 and F4 container cumps. The center LOX tank sump orificewas 19.0+.01)5 inches in diameter, and a liquid level height differentialof approyimately 3.0 inches betkeen the center and outboard LOX tanks waspredicted at IECO (Center tank level higher).The fuel bias for S-IB-6 was 1550 lbm. This fuel weioht. included inthe predicted residual, waspellant residual due to offbe used during a nominal fl iData used in evaluating thetwo discrete probe racks ofthree probes in OC, 01, andF2, and F4; and fuel deplet il

available for consumption-to-minimize pro-nominal conditicns and nas not expected toght.S-IB stage propellant usage consisted offifteen probes each in tanks Fl and F3;03; cutoff level sensors in tanks 02, 04,on probes in the F2 and F4 sumps.

The cutoff sequence on SIB-6 was ini tiated by a signal from the cutofflevel sensor in tank 02 at 135.34 seconds. The IECO signal k;as received3.32 seconds later at 138.66 seconds. OECO was ini tiated 3.68 secondsafter IECO at 142.34 seconds by the Engine Ul thrust OK pressure switches.Fuel depletion probes were not actuated prior to retro motor igni tion.Based on discrete probe data, liquid levels in the fuel tanks were nearlyequal and approximately 23.2 inches above theoretical tank bottom at IECO.This level represents a mass of 11,012 ltrn of fuel onboard. At that t ime11,401 lbm of LOX remained onboard. Corresponding liquid height in thecenter tank was approximately 15.3 inches and average height in the out-board tanks was approximately 10.7 inches above theoretical tank bottom.Propellants remaining above the main valves after outboard engine decaywere 2394 lbm of LOX and 4803 lbm of fuel. Predicted values for thesequantities were 2650 lbm of LOX and 4630 lbm of fuel.Total LOX and fuel masses above the main propellant valves teginn ing atign ition comMnd are shown in Figures 6-6 and G-7. A sumnary cf the

G-9


65/230

63 0001 ssw im

R

c8

6-10


66/230

propellants remaining at major event times is presented in Table 6-4.Table 6-4. S-16 Propellant liass History

PREDICTED (LS:')EVENT FUEL LOX TOTA L

Ionition Com-and 279,579 632,016 911.5951U Umbilical Disconnect 276.314 620,974 697,268IECO 10.243 10,436 20,679OEC@ 5.986 3,297 9,284SeDaration 4,898 2,734 7,632Zero Thrust 4,63n 2.650 7.280

6.6.6 S-IB PRESSURIZATION SYSTEM6.6.1 Fuel Pressurization Syste

Documents

Saturn 1B Launch Vehicle Flight Evaluation Report, SA-206, Skylab-2