STS-51-I

Mission Parameters

Mission Highlights

The five-man STS 51-I crew included Joe H. Engle, commander; Richard O. Covey, pilot; and three mission specialists James van Hoften, John M. Lounge and William F. Fisher. Their primary mission was to deploy three commercial communications satellites and retrieve and repair IV-3 which was deployed during the STS 51-D mission in April 1985 and had malfunctioned. In addition, a middeck materials processing experiment was flown.

The three communications satellites included l, a multi-purpose spacecraft owned by Australia; the ASC-l owned and operated by the American Satellite Co.; and IV-4 leased to the Department of Defense by its builder, the Hughes Co. Both l and ASC-l were deployed on launch day, Aug. 27. IV-4, was deployed two days later. All three achieved proper geosynchronous orbits and became operational.

On the fifth day of the mission, astronauts Fisher and van Hoften began repair efforts on the malfunctioning IV-3 following a successful rendezvous maneuver with Discovery. The effort was slowed because of a problem in the RMS elbow joint. In any event, after a second EVA by Fisher and van Hoften, the lever was repaired, permitting commands from the ground to activate the spacecraft's systems and eventually sending it into its proper geosynchronous orbit. The two EVAs took ll hours and 27 minutes.

Discovery landed on Runway 23 at Edwards AFB at 6:16 a.m. PDT on Sept. 3. The flight took 7 days, 2 hours, 18 minutes, 42 seconds, completing 111 orbits of the Earth.

Three communications satellites deployed: ASC-1 , for American Satellite Company; AUSSAT-1, an Australian Communications Satellite; and SYNCOM IV-4, the Synchronous Communications Satellite. ASC-1 and AUSSAT-1 both attached to Payload Assist Module-D (PAM-D) motors. SYNCOM IV-4 (also known as LEASAT-4) failed to function after reaching correct geosynchronous orbit. Fisher and van Hoften performed 11 hours, 27 minutes of space walk. Part of time spent retrieving, repairing and redeploying LEASAT-3, deployed on Mission 51-D. Middeck Payload: Physical Vapor Transport Organic Solid Experiment (PVTOS).

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