magellan post launch mission operation report

8/8/2019 Magellan Post Launch Mission Operation Report

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NI\S/\Na tional Ae ronau tic s andSpace AdministrationWashington, D.C.20546 JUL 3 I ,t)r' ,

y 10Attn ofELTO: A/AdministratorFROM: E/Associate Administrator for Space Science andApplicationsSUBJECT: Magellan Post Launch Mission Operation Report

The enclosed Magellan Post Launch Mission Operation Report isherein submitted as required by HQMI 8610.1B dated December 27,1982. \ . _ , < JL. A. FiskEnclosure


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NI\S/\National Aeronautics andSpace Administration

Post-Launch M ission Operation ReportO FF IC E O F SP AC E S CIE NC E AND APP LIC AT IO NS Report No. E -8 4 4-8 9 -3 0-0 1

IMage l lanThe Magel/an spacecraftand its IUS booster beingdeployed from the shuttleAtlantis' cargo bay on May4, 1989. One hour later, theIUS inserted Mageflan ontoa 15-month trajectory toVenus.


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FOREWARD

MISSION OPERATION REPORTS are published expressly for the use ofNASA senior management. The purpose of these reports is toprovide NASA senior management with timely, complete, anddefinitive information on flight mission plans, and to establishofficial mission objectives which provide the basis forassessment of mission accomplishment.Reports are prepared and issued for each flight project justprior to launch. Following launch, updated reports are issuedfor each mission to keep management currently informed ofdefinitive mission results as provided in NASA ManagementInstruction HQMI 8610.IB.These reports are sometimes highly technical and are forpersonnel having program/project management responsibilities.The Public Affairs Division publishes a comprehensive series ofreports on NASA flight missions which are available fordissemination to the news media.

Prepared bySOLAR SYSTEM EXPLORATION DIVISIONNASA Headquarters

Published and Distributed byHEADQUARTERS OPERATIONSNASA Headquarters


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Magellan Post Launch Mission operations ReportReport No. E-844-89-30-01

Ref: Magellan Mission Operations Report (Prelaunch)Report No. E-844-89-30--01, April 13, 1989

Magellan was successfully launched by the Space Shuttle Atlantisfrom the Kennedy Space Center at 2:47 p.m. EDT on May 4, 1989.The Inertial Upper stage (IUS) booster and attached MagellanSpacecraft were successfully deployed from Atlantis on Rev. 5 asplanned, at 06:14 hrs Mission Elapsed Time (MET). The two IUSpropulsion burns which began at 07:14 hrs MET and were completedat 07:22 hrs MET, placed the Magellan Spacecraft almost perfectlyon its preplanned trajectory to Venus. The IUS was jettisoned at07:40 hrs MET and Magellan telemetry was immediately acquired bythe Deep Space Network (DSN). A spacecraft trajectory correctionmaneuver was performed on May 21 and the spacecraft is in theplanned standard cruise configuration with all systems operatingnominally.An initial attempt was made to launch Atlantis on April 28, 1989,but the launch was scrubbed at T-31 sec due to a failure of theliquid hydrogen recirculation pump on Space Shuttle MainEngine #1. The countdown had proceeded smoothly until T-20 minwheri +he Magellan radio receiver "locked-on" the MIL 71 UnifiedS-Band (USB) transmission as the transmitter power was increasedfrom 2 kw to 10 kw in support of the orbiter launch. During theplanned hold at T-9 min, the USB was confirmed as the source ofthe receiver "lockl! and Magellan's launch readiness wasreaffirmed. In addition a five-minute extension of the T-9 holdoccurred when a range safety computer went off-line, creating aloss of redundancy in the range safety computer network.Following resumption of the countdown, both the orblter andMagellan flows proceeded smoothly until the launch was scrubbedat T-31 sec.While the orbiter was being readied for another launch attempt,the receiver lock anomaly was thoroughly investigated and changesnegotiated to the nominal launch support plan. Specifically,MIL 71 would delay the time when it went to high power until T-11minutes and would also shift its frequency lower in an attempt toavoid Magellan receiver lock-up.On May 4, the launch was scheduled at 1:48 p.m. EDT but wasdelayed 59 min due to unacceptable cloud cover and excessivecrosswinds at the Shuttle Landing Facility (SLF) Return-to-Launch-site runway. Weather conditions were declared acceptable


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for launch at 2:42 p.m. EDT and Atlantis was successfullylaunched at 2:47 p.m. EDT with 5 min remaining in the launchwindow. The Magellan receiver lock anomaly did not reappearduring the countdown.Atlantis compensated for the delay in launch time by yaw-steeringinto the correct orbit plane. On-orbit events proceeded smoothlywith the deployment and subsequent IUS propUlsive burns occurringas scheduled. The performance of the IUS was as predicted andplaced the Magellan Spacecraft well within the one-sigmapredicted aim point dispersion area. The Magellan solar panelswere deployed prior to the IUS burns and were confirmed to be"latched" at initial DSN telemetry acquisition followingIUS/Magellan separation.The Magellan Spacecraft, operating in its nominal cruisecondition, proceeded with its initial cruise activities. Thefirst Momentum Wheel desaturation was successfully accomplishedat 8:30 p.m. EDT on May 5, 1989. These desaturation events arenow nominally occurring twice daily. The first Star Trackercalibration was attempted on May 5, 1989 but was unsuccessful dueto improperly adjusted star magnitude thresholds. New starthresholds were subsequently uplinked to the spacecraft and thesecond star Tracker calibration was successfully performed onMay 6, 1989. Successful Star Tracker calibrations are nowconducted daily.Slight overheating of the Rocket Engine Module (REMis) and theSolid Rocket Motor (SRM) has been observed when the spacecraftattitude is such that the sun shines directly into the thrusternozzles. This overheating is not present when the spacecraftattitude is changed. Test data indicate that both the REMis andthe SRM will experience elevated temperatures when the High GainAntenna is pointed toward Earth for the Very Long BaselineInterferometry (VLBI) tracking this summer, but the temperaturesshould remain within limits. Thereafter, the spacecraft attitudewill not be conducive to REM and SRM overheating during the restof cruise and the nominal mapping mission.Due to the near perfect injection by the IUS, the initialMagellan Trajectory Correction Maneuver (TCM-1) required avelocity change of only 2.97 m/s. The maneuver was successfullyexecuted on May 21, 1989 and was within 1.1% of the plannedvelocity change. Two more TCM's are planned next year toprecisely adjust the trajectory for VOl. However, the two TCMsare predicted to require less than 2.0 m/s in total velocitychange. At the present time 71 kg of hydrazine margin isavailable out of a total useable propellant mass of 130 kg, morethan enough to successfully complete the Magellan mission. othercruise activities have been successfully completed as planned,the most recent being the arming of the SRM which is used toplace Magellan in Venus orbit. This SRM arming removes the lastremaining Shuttle inhibit.


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In summary, Magellan is cruising normally on its way to Venus.All spacecraft subsystems are performing well. Figure 1indicates the major spacecraft cruise activities which areplanned between now and VOl.

ty~~J J ! ; J ~ W 1 ? ' ;;P~7William L. PiotrowskiMagellan Program ManagerSolar System Exploration DivisionOffice of Space Science and Applications


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FIGURE 1, SIGNIFICANT MAGELLAN CRUISE EVENTS

LAUNCH MAY 4, 1989PLAYBACK OF RECORDEDLAUNCH DATA MAY 12, 1989

OPEN PYRO VALUE MAY :4, 1989TCM-1 MAY 21, 1989ARM SRM JUNE 5, 1989BEGIN VLBI JUNE 28, 1989GYRO CALIBRATION JULY 10, 1989POINT MGA TO EARTH SEPTEMBER 8, 1989TEST RADAR SYSTEM NOVEMBER, 1989TURN ON TWTA APRIL, 1990TCM-2 APRIL, 1990TCM-3 JULY, 1990VOl AUGUST, 1990

magellan post launch mission operation report

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