Wednesday, January 22, 1992

STS-51-D (Discovery)

 1985-028A


After cancellation of 51-E and replanning, the mission was referred to in some internal documents as 51-DR or 51D(R).

After ET sep, a test to dump excess fuel was performed; the LOX vent torque was larger than expected and put Discovery into a 45 degree roll, which was quickly removed by RCS firings.

Deployment of the Anik satellite went smoothly, but Syncom failed to boot up after ejection. Discovery made a burn to reverse its separation maneuver as a plan was developed to fix the problem. A lever on the side of the satellite is normally knocked to the on position by the system that spins the Syncom out of the payload bay; triggering the lever is meant to active the electronics on the satellite. NASA's theory was that the lever had not been triggered. On April 15 the astronauts assembled two 'flyswatter' devices in the cabin, and the next day Hoffman and Griggs made a spacewalk to attach them to the RMS arm. On Apr 17 Discovery reapproached Syncom and used the robot arm to swat the Syncom's lever. The flyswatter made contact with the lever twice during the encounter but with no effect. Plans were drawn up to repair the satellite on a subsequent mission.


STS 51-D mission events 
 

DateTimeEventOrbit  

 
1985 Mar 23   Roll to VAB VAB 
1985 Mar 28   Rollout  LC39A 
1985 Apr 12  1359:05  Launch from LC39A 
 1401:12  SRB sep at 46.7 km 
 1407:57  MECO at 109.9 km 
 1408:16  ET sep at 112.7 km  89.75 64 x 459 x 28.5 (dV) 
 1442:20  OMS-2 (2:23) 70m/s  
 1444:43  OMS-2 CO  92.17 302 x 459 x 28.53 
 1534  PLBD open 
 2012  RMS tests 
 2037  RMS checkout complete 
 2338:38  Anik C1 deploy 
 2354?  SEP-1 (OMS-3 RH 13s) 3m/s  92.30 314 x 460 x 28.52  
1985 Apr 13  1458:22  Leasat deploy 
 1510Stationkeep with Syncom IV-3 
 1514  SEP-2 (OMS-4 8s) 4m/s  92.30 314 x 460 x 28.52 
 1543  Planned Syncom PKM burn 
 1636  RETRO (OMS-5 8 s) 4m/s burn to stay 65 km from Syncom 
1985 Apr 14  1647   92.32 314 x 461 x 28.52 
1985 Apr 15  1045   92.31 314 x 460 x 28.52 
 2000  Two flyswatters assembled in cabin 
1985 Apr 16  1219  Airlock at 3.1psi 
 1221  Depressing to zero 
 1225Vacuum reached
 1233HO
 1236  Out in bay
 1240  EVA (Hoffman;Griggs) (03:07, dp =03:10) 
 1250  EV2 biomed sensor failed 
 1315?  Attach `flyswat' device to RMS 
 1350  Flyswat attach complete 
 1420? RMS cradled 
 1507  PSA stowed 
 1519  Ingress 
 1530  HC 
 1535? Repress 
 1550?  EVA complete 
 2054? NSR (OMS-6 LH 12s) 3m/s 
1985 Apr 17  0700 92.31 315 x 459 x 28.52 
 0929  NCC mv  
 1035NC3 (OMS-7 LH 13s) 3m/s 
 1100  TI (OMS-8 LH 9s) 3m/s 
 1200  MC3 burn RCS? 
 1307  At 15m from Syncom  
 1400  Rendezvous Syncom   
 1405  Arm in movement 
 1414:56  RMS contact with Leasat 3 
 1415:30  Second RMS contact with Leasat 3 
 1418  Contact time window closed 
 1422? RMS cradled 
 1430?  Sep (OMS-9/LH 22s) 7m/s  92.54 336 x 461 x 28.5 
1985 Apr 18  1610   92.55 337 x 461 x 28.52 
1985 Apr 19  0831 PLBD closed 
 1244:25  OMS DO (238s) 138m/s 
 1248:23  OMS DO CO 
 1324  Entry 
 1354:28  Landed RW33 KSC 
 1354:36  NGTD 
 1355:31  Wheels stop 
 1820Tow to OPF 

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