STS-51-I

STS-51-I
	van Hoften next to the crippled Syncom IV-3 (Leasat-3) satellite, during the mission's first EVA.
Names	Space Transportation System-20
Mission type	Satellites 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 km (2,919,576 mi)
Orbits completed	112
Spacecraft properties
Spacecraft	Space Shuttle Discovery
Launch mass	118,981 kg (262,308 lb)
Landing mass	89,210 kg (196,670 lb)
Payload mass	17,540 kg (38,670 lb)
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; 1st EVA: 7 hours, 20 minutes; 2nd EVA: 4 hours, 26 minutes;
Start of mission
Launch date	August 27, 1985, 10:58:01 UTC (6:58:01 am EDT)
Launch site	Kennedy, LC-39A
Contractor	Rockwell International
End of mission
Landing date	September 3, 1985, 13:15:43 UTC (6:15:43 am PDT)
Landing site	Edwards, Runway 23
Orbital parameters
Reference system	Geocentric orbit
Regime	Low Earth orbit
Perigee altitude	350 km (220 mi)
Apogee altitude	465 km (289 mi)
Inclination	28.45°
Period	92.00 minutes
Instruments
	Physical Vapor Transport Organic Solid Experiment (PVTOS)
	; STS-51-I mission patch; ; Back row: James D. A. van Hoften, John M. Lounge, William F. Fisher ; Front row: Joe H. Engle, Richard O. Covey Space Shuttle program ← STS-51-F (19) STS-51-J (21) →

Last updated February 16, 2025

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, 1985.

Crew


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

Spacewalks

EVA 1

Personnel: Fisher and van Hoften
Date: August 31, 1985 (≈12:10–19:10 UTC)^[2]
Duration: 7 hours, 20 minutes

EVA 2

Personnel: Fisher and van Hoften
Date: September 1, 1985 (≈12:10–16:30 UTC)^[2]
Duration: 4 hours, 26 minutes

Crew seat assignments

Seat^[2]	Launch	Landing	Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck.
1	Engle
2	Covey
3	van Hoften	Fisher
4	Lounge
5	Fisher	van Hoften
6	Unused
7	Unused

Launch

Attempt	Planned	Result	Turnaround	Reason	Decision point	Notes
1	24 Aug 1985, 8:38:00 am	Scrubbed	—	Weather	24 Aug 1985, 9:06 am (T−00:05:00)	Thunderstorms in the KSC area and a ship entering the SRB recovery area
2	25 Aug 1985, 7:57:00 am	Scrubbed	0 days 23 hours 19 minutes	Technical	25 Aug 1985, 8:11 am (T−00:09:00 hold)	Computer failure
3	27 Aug 1985, 6:58:01 am	Success	1 day 23 hours 1 minute			Launch delayed 3 minutes, 1 second for weather and ship in entering SRB recovery area.

Mission summary

Discovery launched at 6:58 a.m. 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,^[3] and the second because the backup orbiter computer failed and had to be replaced.^[4] The successful launch on August 27, 1985, 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 D. A. 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 (Leasat-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 Corporation (ASC); and Syncom IV-4 (Leasat-4), leased to the Department of Defense (DoD) by its builder, Hughes Space and Communications. Both Aussat-1 and ASC-1 were deployed on the day of the launch, August 27, 1985. Syncom IV-4 (Leasat-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 with the Remote Manipulator System (Canadarm) 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 a.m. 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 112 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 Project Gemini, 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.^[5]

Flight Day	Song	Artist/Composer
Day 2	"Waltzing Matilda"^[6]	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"^[7]	Willie Nelson
Day 8	"Living in the USA"	Linda Ronstadt

Gallery

Launch of Space Shuttle Discovery
Deployment of Aussat-1
Deployment of ASC-1
Deployment of Syncom IV-4 (Leasat-4)
Space Shuttle Discovery Landing

References

↑ "STS-51-I Press Kit" (PDF). NASA. February 11, 2015. This article incorporates text from this source, which is in the public domain.
1 2 3 "STS-51I". Spacefacts. Retrieved February 26, 2014.
↑ O'Toole, Thomas (August 24, 1985). "Rain Delays Discovery's Liftoff". The Washington Post. Retrieved November 16, 2024.
↑ O'Toole, Thomas (August 26, 1985). "Computer Failure Grounds Shuttle". The Washington Post. Retrieved November 16, 2024.
↑ Fries, Colin (June 25, 2007). "Chronology of Wakeup Calls" (PDF). NASA. Archived from the original (PDF) on December 20, 2023. Retrieved August 13, 2007. This article incorporates text from this source, which is in the public domain .
↑ Chosen to waken the crew as they passed over Australia.
↑ Chosen due to Hurricane Elena, which had been observed earlier from Discovery.

External links

NASA mission summary Archived December 9, 2012, at the Wayback Machine
STS-51I Video Highlights Archived July 18, 2012, at the Wayback Machine

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[1] "STS-51-I Press Kit" (PDF). NASA. February 11, 2015. This article incorporates text from this source, which is in the public domain.

[spacefacts-2] 1 2 3 "STS-51I". Spacefacts. Retrieved February 26, 2014.

[3] O'Toole, Thomas (August 24, 1985). "Rain Delays Discovery's Liftoff". The Washington Post. Retrieved November 16, 2024.

[4] O'Toole, Thomas (August 26, 1985). "Computer Failure Grounds Shuttle". The Washington Post. Retrieved November 16, 2024.

[chronology-5] Fries, Colin (June 25, 2007). "Chronology of Wakeup Calls" (PDF). NASA. Archived from the original (PDF) on December 20, 2023. Retrieved August 13, 2007. This article incorporates text from this source, which is in the public domain .

[6] Chosen to waken the crew as they passed over Australia.

[7] Chosen due to Hurricane Elena, which had been observed earlier from Discovery.

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v t e Space Shuttle Discovery (OV-103)
Completed flights	STS-41-D STS-51-A STS-51-C STS-51-D STS-51-G STS-51-I STS-26 STS-29 STS-33 STS-31 STS-41 STS-39 STS-48 STS-42 STS-53 STS-56 STS-51 STS-60 STS-64 STS-63 STS-70 STS-82 STS-85 STS-91 STS-95 STS-96 STS-103 STS-92 STS-102 STS-105 STS-114 STS-121 STS-116 STS-120 STS-124 STS-119 STS-128 STS-131 STS-133
Status	Retired
On display	Steven F. Udvar-Hazy Center, Washington, D.C.
Related	Destiny in Space (1994 documentary)

v t e ← 1984 Orbital launches in 1985 1986 →
January	STS-51-C (USA-8)
February	USA-9 Arabsat-1A Brasilsat A1
March	Geosat Intelsat VA F-10
April	STS-51-D (Anik C1, Leasat 3) STS-51-B (Nusat)
May	GStar-1 Telecom 1B
June	Soyuz T-13 STS-51-G (Morelos 1, Arabsat-1B, Telstar 3D, SPARTAN-101) Progress 24 Intelsat VA F-11
July	Giotto Kosmos 1669 STS-51-F (PDP)
August	STS-51-I (Aussat A1, ASC-1, Leasat 4)
September	Spacenet 3 Soyuz T-14 Kosmos 1686 Intelsat VA F-12
October	STS-51-J (USA-11, USA-12) USA-10 STS-61-A (GLOMR)
November	STS-61-B (Morelos 2, Aussat A2, Satcom K2, OEX, EASE/ACCESS)
Unknown month	Sakigake Kosmos 1616 Kosmos 1617 Kosmos 1618 Kosmos 1619 Kosmos 1620 Kosmos 1621 Kosmos 1622 Molniya-3 No.36 Kosmos 1623 Kosmos 1624 Gorizont No.21L Kosmos 1625 Kosmos 1626 Kosmos 1627 Kosmos 1628 Meteor-2 No.13 Kosmos 1629 Kosmos 1630 Kosmos 1631 Kosmos 1632 Kosmos 1633 Kosmos 1634 Kosmos 1635 Kosmos 1636 Kosmos 1637 Kosmos 1638 Kosmos 1639 Kosmos 1640 Kosmos 1641 Kosmos 1642 Ekran No.28L Kosmos 1643 Kosmos 1644 Unnamed Kosmos 1645 Kosmos 1646 Kosmos 1647 Kosmos 1648 Prognoz 10 Kosmos 1649 Kosmos 1650 Kosmos 1651 Kosmos 1652 Kosmos 1653 Kosmos 1654 Molniya-3 No.39 Kosmos 1655 Kosmos 1656 Kosmos 1657 Kosmos 1658 Kosmos 1659 Kosmos 1660 Kosmos 1661 Kosmos 1662 Kosmos 1663 Unnamed Kosmos 1664 Kosmos 1665 Kosmos 1666 Kosmos 1667 Kosmos 1668 Molniya-3 No.37 Kosmos 1670 Kosmos 1671 Transit-O 24 Transit-O 30 Kosmos 1672 Kosmos 1672 Kosmos 1673 Kosmos 1674 Gran' No.26L Kosmos 1675 Kosmos 1676 Suisei Molniya-1 No.61 Kosmos 1677 Unnamed Kosmos 1678 Kosmos 1679 Kosmos 1680 Kosmos 1681 ECS-3 Kosmos 1682 Kosmos 1683 Kosmos 1684 Kosmos 1685 Kosmos 1687 Kosmos 1688 Kosmos 1689 Molniya-3 No.38 Kosmos 1690 Kosmos 1695 Kosmos 1692 Kosmos 1693 Kosmos 1694 Kosmos 1691 Kosmos 1696 Fanhui Shi Weixing 8 Kosmos 1697 Kosmos 1698 Molniya-1 No.73 Unnamed Meteor-3 No.2 Kosmos 1699 Kosmos 1700 Molniya-1 No.56 Kosmos 1701 Kosmos 1702 Gran' No.28L Kosmos 1703 Kosmos 1704 Kosmos 1705 Kosmos 1706 Kosmos 1707 USA-13 USA-14 Kosmos 1708 Kosmos 1709 Molniya-3 No.40 Kosmos 1710 Kosmos 1711 Kosmos 1712 Meteor-2 No.14 Kosmos 1713 Kosmos 1714
Payloads are separated by bullets ( · ), launches by pipes ( \| ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets).