Mission Specialist James Van Hoften working on the crippled Syncom IV-3 satellite
|Mission type||Satellite deployment
|Mission duration||7 days, 2 hours, 17 minutes, 42 seconds|
|Distance travelled||4,698,602 kilometres (2,919,576 mi)|
|Spacecraft||Space Shuttle Discovery|
|Launch mass||118,981 kilograms (262,309 lb)|
|Landing mass||89,210 kilograms (196,674 lb)|
|Payload mass||29,772 kilograms (65,635 lb)|
|Members||Joe H. Engle
Richard O. Covey
James D. A. van Hoften
John M. Lounge
William F. Fisher
|Start of mission|
|Launch date||27 August 1985, 10:58:01UTC|
|Launch site||Kennedy LC-39A|
|End of mission|
|Landing date||3 September 1985, 13:15:43UTC|
|Landing site||Edwards Runway 23|
|Perigee||350 kilometres (220 mi)|
|Apogee||465 kilometres (289 mi)|
Back row L-R: van Hoften, Lounge, Fisher
STS-51-I was the 20th mission of NASA's Space Shuttle program and the sixth flight of Space Shuttle Discovery. During the mission, Discovery deployed three communications satellites into orbit. The mission launched from Kennedy Space Center, Florida, on 27 August 1985, and landed at Edwards Air Force Base, California, on 3 September.
|Commander||Joe H. Engle
Second and last spaceflight
|Pilot||Richard O. Covey
|Mission Specialist 1||James D. A. van Hoften
Second and last spaceflight
|Mission Specialist 2||John M. Lounge
|Mission Specialist 3||William F. Fisher
- Fisher and van Hoften – EVA 1
- EVA 1 Start: 31 August 1985
- EVA 1 End: 31 August 1985
- Duration: 7 hours, 20 minutes
- Fisher and van Hoften – EVA 2
- EVA 2 Start: 1 September 1985
- EVA 2 End: 1 September 1985
- Duration: 4 hours, 26 minutes
Mission summary 
Discovery launched at 6:58 am EDT on 27 August 1985. Two earlier launch attempts, one on 24 August and another on 25 August, were scrubbed – the first because of poor weather, and the second because the backup orbiter computer failed and had to be replaced. The successful launch on 27 August took place just as an approaching storm front reached the launch pad area.
The five-man STS 51-I crew included Joe H. Engle, commander; Richard O. Covey, pilot; and James van Hoften, John M. Lounge, and William F. Fisher, mission specialists. Their primary mission was to deploy three commercial communications satellites and retrieve and repair the Syncom IV-3 satellite, which had been deployed during the STS 51-D mission in April 1985, but had malfunctioned. In addition, a mid-deck materials processing experiment, the Physical Vapor Transport Organic Solid Experiment (PVTOS), was flown aboard Discovery.
The three communications satellites were Aussat 1, a multi-purpose spacecraft owned by Australia; ASC-1, owned and operated by the American Satellite Company; and Syncom IV-4, leased to the Department of Defense by its builder, Hughes Co. Both Aussat 1 and ASC-1 were deployed on the day of the launch, 27 August. Syncom IV-4 was deployed two days later. All three achieved their planned geosynchronous orbits and became operational.
On the fifth day of the mission, astronauts Fisher and van Hoften began repair efforts on the malfunctioning Syncom IV-3, following a successful rendezvous maneuver by Discovery. The effort was slowed by a problem in the Remote Manupulator System elbow joint. After a second EVA by Fisher and van Hoften, the satellite's control lever was repaired, permitting commands from the ground to activate the spacecraft's systems and eventually send it into its proper geosynchronous orbit. The two EVAs lasted a total of 11 hours and 27 minutes.
Discovery landed on Runway 23 at Edwards Air Force Base at 6:16 am PDT on 3 September 1985. The flight lasted a total of 7 days, 2 hours, 18 minutes and 42 seconds, during which the shuttle completed 111 orbits of the Earth.
Wake-up calls 
NASA began a tradition of playing music to astronauts during the Gemini program, and first used music to wake up a flight crew during Apollo 15. Each track is specially chosen, often by the astronauts' families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.
|Day 2||"Waltzing Matilda"|
|Day 3||"Over the Rainbow"||Judy Garland|
|Day 4||"I Saw the Light"||Willie Nelson|
|Day 5||"I Get Around"||Beach Boys|
|Day 6||"Lucky Old Sun"||Willie Nelson|
|Day 7||"Stormy Weather"||Willie Nelson|
|Day 8||"Living in the USA"||Linda Ronstadt|
See also 
- Engle exceeded an altitude of 80 kilometres (50 mi) three times as a test pilot in the X-15 program; these are regarded spaceflights by the US Air Force but not by any other body and did not reach what is recognised internationally as the edge of space. STS-51-I was his second Space Shuttle flight, and his second flight above the Kármán line.
- Fries, Colin (25 June 2007). "Chronology of Wakeup Calls" (PDF). NASA. Retrieved 13 August 2007.
- Chosen to waken the crew as they passed over Australia.
- Chosen due to Hurricane Elena, which had been observed earlier from Discovery.