||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (July 2009)|
Mission Specialist Dale Gardner holds up a "For Sale" sign, referring to the malfunctioning Palapa B2 and Westar 6 satellites.
|Mission type||Satellite deployment
|Mission duration||7 days, 23 hours, 44 minutes, 56 seconds|
|Distance travelled||5,293,786 kilometres (3,289,406 mi)|
|Spacecraft||Space Shuttle Discovery|
|Launch mass||119,442 kilograms (263,324 lb)|
|Landing mass||94,123 kilograms (207,505 lb)|
|Payload mass||17,375 kilograms (38,305 lb)|
|Start of mission|
|Launch date||8 November 1984, 12:15:00UTC|
|Launch site||Kennedy LC-39A|
|End of mission|
|Landing date||16 November 1984, 11:59:56UTC|
|Landing site||Kennedy SLF Runway 15|
|Perigee||332 kilometres (179 nmi)|
|Apogee||354 kilometres (191 nmi)|
L-R: Gardner, Walker, Fisher, Hauck, Allen
STS-51-A was the 14th flight of NASA's Space Shuttle program, and the second flight of Space Shuttle Discovery. The mission launched from Kennedy Space Center on 8 November 1984, and landed just under eight days later on 16 November.
STS-51-A marked the first time a shuttle deployed two communications satellites, and retrieved from orbit two other communications satellites. The Canadian Anik D2 and Syncom IV-1 satellites were both successfully deployed by the crew of Discovery. Palapa B2 and Westar 6, meanwhile, had been deployed during the STS-41-B mission earlier in the year, but had been placed into improper orbits due to the malfunctioning of their kick motors; they were both safely recovered and returned to Earth during STS-51-A.
|Pilot||David M. Walker
|Mission Specialist 1||Joseph P. Allen
Second and last spaceflight
|Mission Specialist 2||Anna Lee Fisher
|Mission Specialist 3||Dale Gardner
Second and last spaceflight
- Allen and Gardner – EVA 1
- EVA 1 Start: 12 November 1984 – 13:25 UTC
- EVA 1 End: 12 November 1984 - 19:25 UTC
- Duration: 6 hours, 00 minutes
- Allen and Gardner – EVA 2
- EVA 2 Start: 14 November 1984 – 11:09 UTC
- EVA 2 End: 14 November 1984 – 16:51 UTC
- Duration: 5 hours, 42 minutes
Mission summary 
STS-51-A was launched from Florida's Kennedy Space Center (KSC) at 7:15 am EST, 8 November 1984, less than a month after the STS-41-G flight. A launch attempt the day before was scrubbed at T-minus 20 minutes due to high shear winds in the upper atmosphere.
The five-person flight crew consisted of Frederick H. Hauck, commander, on his second flight; pilot David M. Walker; and three mission specialists – Anna L. Fisher, Dale A. Gardner and Joseph P. Allen. Both Gardner and Allen were making their second shuttle flights.
The two communications satellites successfully deployed were Anik D2 (on the second day of the mission) and Syncom IV-1, also known as Leasat 1 (on the third day).
The orbiter then began a series of maneuvers to meet up with the first of the two satellites to be recovered, Palapa B2. The orbits of both satellites had been lowered by ground commands from about 600 miles (970 km) to 210 miles (340 km) to facilitate recovery operations. On day five of the mission, Discovery rendezvoused with Palapa. Mission specialists Allen and Gardner performed an EVA, capturing the satellite with a device known as a "Stinger," which was inserted into the satellite's apogee motor nozzle by Allen. The satellite's rotation was slowed to 1 RPM, and Gardner, operating from a position on the end of the RMS, attempted unsuccessfully to grapple the satellite. Allen was able to manually maneuver the satellite into its cradle with Gardner's help, further aided by the RMS, which was operated by Fisher. The successful, improvised rescue effort took two hours.
The recovery of Westar 6 was not as difficult, and took place a day later. This time, Gardner, using the same muscle-power technique Allen had used for Palapa B2's rescue, easily captured the satellite. With Allen's help, he placed it in a cradle in the cargo bay.
The STS-51-A mission also carried the Diffused Mixing of Organic Solutions (DMOS) experiment. It was the first of a series of comprehensive organic and polymer science experiments sponsored by 3M Corporation. This mid-deck experiment was successful, and the proprietary results of the chemical mixes were turned over to 3M. One other experiment, a radiation-monitoring experiment, was also performed.
The satellite recoveries on STS-51-A were the last untethered spacewalks until 1994, and marked the last use of the Manned Maneuvering Unit. In 1994, the Simplified Aid for EVA Rescue (SAFER) was tested on STS-64. On all subsequent spacewalks conducted by both NASA and the Soviet/Russian space agencies, the astronauts were tethered to the craft by some means.
The second mission of Discovery ended at 7 am EST on 16 November 1984 with a successful landing on Runway 15 at KSC. The flight completed 126 orbits, and lasted 7 days, 23 hours and 45 minutes. It was the third shuttle landing at KSC, and the fifth and last shuttle mission of 1984.
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||"Marine Corps Hymn"|
|Day 3||"Theme from For a Few Dollars More"||Ennio Morricone|
See also 
- NASA mission summary
- Video from post mission press conference with extensive footage available for download at www.archive.org The Internet Archive
- STS-51A Video Highlights