STS-51-I SYNCOM IV-3 EVA by James van Hoften.jpg
Van Hoften next to the crippled Syncom IV-3 satellite, during the mission's first EVA
Mission typeSatellite deployment
Satellite repair
COSPAR ID1985-076A
SATCAT no.15992
Mission duration7 days, 2 hours, 17 minutes, 42 seconds
Distance travelled4,698,602 kilometres (2,919,576 mi)
Orbits completed112
Spacecraft properties
SpacecraftSpace Shuttle Discovery
Launch mass118,981 kilograms (262,309 lb)
Landing mass89,210 kilograms (196,674 lb)
Payload mass17,540 kilograms (38,660 lb)[1]
Crew size5
EVA duration11 hours, 46 minutes
First: 7 hours, 20 minutes
Second: 4 hours, 26 minutes
Start of mission
Launch dateAugust 27, 1985, 10:58:01 (1985-08-27UTC10:58:01Z) UTC
Launch siteKennedy LC-39A
End of mission
Landing dateSeptember 3, 1985, 13:15:43 (1985-09-03UTC13:15:44Z) UTC
Landing siteEdwards Runway 23
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Perigee altitude350 kilometres (220 mi)
Apogee altitude465 kilometres (289 mi)
Inclination28.45 degrees
Period92 min
Sts-51-i-patch.png STS-51-I crew.jpg
Back row L-R: van Hoften, Lounge, Fisher
Front row L-R: Engle, Covey 

STS-51-I (formerly STS-27) 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.


Position Astronaut
Commander Joe H. Engle
Second and last NASA (final overall) spaceflight
Pilot Richard O. Covey
First spaceflight
Mission Specialist 1 James D. A. van Hoften
Second and last spaceflight
Mission Specialist 2 John M. Lounge
First spaceflight
Mission Specialist 3 William F. Fisher
Only spaceflight


  • Fisher and van Hoften – EVA 1
  • EVA 1 Start: August 31, 1985
  • EVA 1 End: August 31, 1985
  • Duration: 7 hours, 20 minutes
  • Fisher and van Hoften – EVA 2
  • EVA 2 Start: September 1, 1985
  • EVA 2 End: September 1, 1985
  • Duration: 4 hours, 26 minutes

Crew seating arrangements

Seat[2] Launch Landing STS-121 seating assignments.png
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


Attempt Planned Result Turnaround Reason Decision point Weather go (%) Notes
1 24 Aug 1985, 10:55:00 am scrubbed weather  ​(T-5:00)
2 25 Aug 1985, 10:55:00 am scrubbed 1 day, 0 hours, 0 minutes technical number 5 computer failure
3 27 Aug 1985, 10:58:01 am success 2 days, 0 hours, 3 minutes launch delayed three minutes, one second for weather and ship in entering SRB recovery area

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.


Mission insignia

The insignia depicts an American bald eagle, trailing red and white stripes, and pushing a boundary layer forward. The 19 stars, along with the eagle, are references to the 20th shuttle mission (with the eagle representing the orbiter and thus being the 20th 'star'). Lining the patch are the surnames of the crew members.

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]

Flight Day Song Artist/Composer
Day 2 "Waltzing Matilda"[4] Banjo Paterson
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"[5] Willie Nelson
Day 8 "Living in the USA" Linda Ronstadt

See also


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

  1. ^ "STS-51-I Press Kit" (PDF). NASA.
  2. ^ "STS-51I". Spacefacts. Retrieved February 26, 2014.
  3. ^ Fries, Colin (June 25, 2007). "Chronology of Wakeup Calls" (PDF). NASA. Retrieved August 13, 2007.
  4. ^ Chosen to waken the crew as they passed over Australia.
  5. ^ Chosen due to Hurricane Elena, which had been observed earlier from Discovery.

External links

  • NASA mission summary
  • STS-51I Video Highlights