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Discovery attempts to activate the Syncom IV-3 satellite via a "flyswatter" device attached to the RMS
|Mission type||Satellite deployment|
|Mission duration||6 days, 23 hours, 55 minutes, 23 seconds|
|Distance travelled||4,650,658 kilometres (2,889,785 mi)|
|Spacecraft||Space Shuttle Discovery|
|Launch mass||113,802 kilograms (250,891 lb)|
|Landing mass||89,818 kilograms (198,014 lb)|
|Payload mass||13,039 kilograms (28,747 lb)|
Karol J. Bobko|
Donald E. Williams
M. Rhea Seddon
S. David Griggs
Jeffrey A. Hoffman
Charles D. Walker
Edwin J. Garn
|EVA duration||3 hours, 6 minutes|
|Start of mission|
|Launch date||April 12, 1985, 13:59:05UTC|
|Launch site||Kennedy LC-39A|
|End of mission|
|Landing date||April 19, 1985, 13:54:28UTC|
|Landing site||Kennedy SLF Runway 33|
|Perigee||300 kilometres (160 nmi)|
|Apogee||452 kilometres (244 nmi)|
|Epoch||April 14, 1985 |
Back row L-R: Griggs, Walker, Garn
Front row: L-R: Bobko, Williams, Seddon, Hoffman.
STS-51-D was the 16th flight of NASA's Space Shuttle program, and the fourth flight of Space Shuttle Discovery.  The launch of STS-51-D from Kennedy Space Center (KSC), Florida, on April 12, 1985 was delayed by 55 minutes, after a boat strayed into the restricted Solid Rocket Booster (SRB) recovery zone. STS-51-D was the third shuttle mission to be extended.
On April 19, after a week-long flight, Discovery conducted the fifth shuttle landing at KSC. The shuttle suffered extensive brake damage and a ruptured tire during landing. This forced all subsequent shuttle landings to be done at Edwards Air Force Base, California, until the development and implementation of nose wheel steering made landings at KSC more feasible.
Karol J. Bobko|
Donald E. Williams|
|Mission Specialist 1||
M. Rhea Seddon|
|Mission Specialist 2||
S. David Griggs|
|Mission Specialist 3||
Jeffrey A. Hoffman|
|Payload Specialist 1||
Charles D. Walker|
|Payload Specialist 2||
Edwin J. Garn|
|Garn was a
Utah acting as a congressional|
observer. He was the first sitting member of Congress in space.
- Hoffman and Griggs – EVA 1
- EVA 1 Start: April 16, 1985
- EVA 1 End: April 16, 1985
- Duration: 3 hours, 06 minutes
Seats 1–4 are on the Flight Deck. Seats 5–7 are on the Middeck.
During STS-51-D, the shuttle crew deployed two communications satellites: Telesat-I (Anik C1) and Syncom IV-3 (also known as Leasat-3). Telesat-I was attached to a Payload Assist Module (PAM-D) motor and successfully deployed. Syncom IV-3, however, failed to initiate antenna deployment and spin-up, or ignite its perigee kick motor upon deployment. The mission was consequently extended by two days to ensure that the satellite's spacecraft sequencer start lever was in its proper position. Griggs and Hoffman performed an unscheduled EVA to attach homemade "Flyswatter" devices to the shuttle's Remote Manipulator System (RMS). Seddon then engaged the satellite's start lever using the RMS, but again the post-deployment sequence did not begin. 
Discovery's other mission payloads included the Continuous Flow Electrophoresis System (CFES) III, which was flying for sixth time; two Shuttle Student Involvement Program (SSIP) experiments; the American Flight Echo-cardiograph (AFE); two Getaway Specials; a set of Phase Partitioning Experiments (PPE); an astronomical photography verification test; various medical experiments; and "Toys in Space," an informal study of the behavior of simple toys in a microgravity environment, with the results being made available to school students upon the shuttle's return. 
During the shuttle's landing at KSC on April 19, 1985, extensive brake damage was suffered, and a landing gear tire ruptured. This prompted future shuttle flights to land at Edwards Air Force Base, California, until effective nose wheel steering could be implemented to reduce risks during landing.
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||" Top of the World"||The Carpenters|
|Day 3||"Rescue Aid Society"||Song from the Disney film, The Rescuers|
Hoffman and Griggs attach the flyswatter device to the end of the RMS.
This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (July 2009) ( Learn how and when to remove this template message)
- McDowell, Jonathan. "SATCAT". Jonathan's Space Pages. Retrieved March 24, 2014.
- NASA. "STS-51D Press Kit" (PDF). Retrieved December 16, 2009.
- "STS-51D". Spacefacts. Retrieved February 26, 2014.
- Walker, Charles D. (April 14, 2005). "Oral History Transcript". NASA Johnson Space Center Oral History Project (Interview). Interviewed by Johnson, Sandra.
- "STS-51D". NASA. February 18, 2010. Retrieved January 16, 2018.
- Fries, Colin (June 25, 2007). "Chronology of Wakeup Calls" ( PDF). NASA. Retrieved August 13, 2007.