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STS-51-I

Mission Specialist James Van Hoften working on the crippled Syncom IV-3 satellite
Mission type	Satellite deployment Satellite repair
Operator	NASA
COSPAR ID	1985-076A
SATCAT no.	15992
Mission duration	7 days, 2 hours, 17 minutes, 42 seconds
Distance travelled	4,698,602 kilometres (2,919,576 mi)
Orbits completed	112
Spacecraft properties
Spacecraft	Space Shuttle Discovery
Launch mass	118,981 kilograms (262,309 lb)
Landing mass	89,210 kilograms (196,674 lb)
Payload mass	17,540 kilograms (38,660 lb)[1]
Crew
Crew size	5
Members	Joe H. Engle Richard O. Covey James D. A. van Hoften John M. Lounge William F. Fisher
EVAs	2
EVA duration	11 hours, 46 minutes First: 7 hours, 20 minutes Second: 4 hours, 26 minutes
Start of mission
Launch date	August 27, 1985, 10:58:01 (1985-08-27UTC10:58:01Z) UTC
Launch site	Kennedy LC-39A
End of mission
Landing date	September 3, 1985, 13:15:43 (1985-09-03UTC13:15:44Z) UTC
Landing site	Edwards Runway 23
Orbital parameters
Reference system	Geocentric
Regime	Low Earth
Perigee	350 kilometres (220 mi)
Apogee	465 kilometres (289 mi)
Inclination	28.45 degrees
Period	92 min
Back row L-R: van Hoften, Lounge, Fisher Front row L-R: Engle, Covey Space Shuttle program ← STS-51-F STS-51-J →

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 August 27, 1985, and landed at Edwards Air Force Base, California, on September 3.

Crew

Spacewalks

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  Fisher and van Hoften – EVA 1


• 
  EVA 1 Start: August 31, 1985


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  EVA 1 End: August 31, 1985


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  Duration: 7 hours, 20 minutes


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  Fisher and van Hoften – EVA 2


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  EVA 2 Start: September 1, 1985


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  EVA 2 End: September 1, 1985


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  Duration: 4 hours, 26 minutes

Crew seating arrangements

Seat[2]	Launch	Landing	Seats 1–4 are on the Flight Deck. Seats 5–7 are on the Middeck.
S1	Engle	Engle
S2	Covey	Covey
S3	van Hoften	Fisher
S4	Lounge	Lounge
S5	Fisher	van Hoften

Launch

Mission summary

Discovery launched at 6:58 am EDT on August 27, 1985. Two earlier launch attempts, one on August 24 and another on August 25, 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 August 27 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 Manipulator 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 46 minutes.

Discovery landed on Runway 23 at Edwards Air Force Base at 6:16 am PDT on September 3, 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.

Gallery

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  Deployment of Aussat 1
  

  
  

  
  


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  Deployment of ASC-1
  

  
  

  
  


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  Deployment of Syncom IV-4
  

  
  

  
  

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.^[3]

See also

• List of human spaceflights


• List of Space Shuttle missions

References

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

External links

• NASA mission summary


• STS-51I Video Highlights