STS-51-I was the 20th mission of

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...

program and the sixth flight of Space Shuttle ''Discovery''. During the mission, ''Discovery'' deployed three

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

s into orbit. The mission launched from

Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the National Aeronautics and Space Administration's (NASA) ten field centers. Since December 1968 ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, on August 27, 1985, and landed at

Edwards Air Force Base Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, but its eastern end is in San Bernardino County and a southern arm is in Los Angeles County. The hub of the base is E ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, on September 3, 1985.

Crew

Spacewalks

* '' 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

Launch

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, and the second because the backup orbiter computer failed and had to be replaced. The successful launch on August 27, 1985, took place just as an approaching

storm A storm is any disturbed state of the natural environment or the atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmos ...

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 Syncom (for "synchronous communication satellite") started as a 1961 NASA program for active geosynchronous communication satellites, all of which were developed and manufactured by the Space and Communications division of Hughes Aircraft Comp ...

IV-3 (Leasat-3) satellite, which had been deployed during the

STS-51-D 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 st ...

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 Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

; ASC-1, owned and operated by the

American Satellite Corporation American Satellite Company (ASC) was one of many Fairchild Industries subsidiary companies and was established in partnership with Continental Telephone in 1972. Emanuel Fthenakis was the President and Chief Executive Officer upon the founding of ...

(ASC); and Syncom IV-4 ( Leasat-4), leased to the

Department of Defense Department of Defence or Department of Defense may refer to: Current departments of defence * Department of Defence (Australia) * Department of National Defence (Canada) * Department of Defence (Ireland) * Department of National Defense (Philipp ...

(DoD) by its builder,

Hughes Space and Communications The Hughes Aircraft Company was a major American aerospace and defense contractor founded on February 14, 1934 by Howard Hughes in Glendale, California, as a division of Hughes Tool Company. The company was known for producing, among other prod ...

. 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 orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital ...

s 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 Canadarm or Canadarm1 (officially Shuttle Remote Manipulator System or SRMS, also SSRMS) is a series of robotic arms that were used on the Space Shuttle orbiters to deploy, manoeuvre, and capture payloads. After the Space Shuttle ''Columbia' ...

) 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

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 Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

Mission insignia

The insignia depicts an American

bald eagle The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche as ...

, 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 Project Gemini () was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual ...

, and first used music to wake up a flight crew during

Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the United States' Apollo program and the fourth to Moon landing, land on the Moon. It was the first List of Apollo missions#Alphabetical mission types, J mission, with a ...

. 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.

Gallery

Image:STS-51-I AUSSAT 1 deployment.jpg, Deployment of Aussat-1 Image:STS-51-I ASC-1 deployment.jpg, Deployment of ASC-1 Image:STS-51-I SYNCOM IV-4 deployment.jpg, Deployment of Syncom IV-4 (Leasat-4)

References

External links

NASA mission summary

{{Orbital launches in 1985 Space Shuttle missions Edwards Air Force Base 1985 in spaceflight 1985 in the United States Spacecraft launched in 1985 Spacecraft which reentered in 1985 Satellite servicing missions