STS-51-D was the 16th flight 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, succeedin ...

Space Shuttle program The Space Shuttle program was the fourth human spaceflight program carried out by the U.S. National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. I ...

, and the fourth flight of Space Shuttle ''Discovery''. The launch of STS-51-D 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 196 ...

(KSC),

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 ...

, on April 12, 1985, was delayed by 55 minutes, after a boat strayed into the restricted

Solid Rocket Booster A solid rocket booster (SRB) is a large solid propellant motor used to provide thrust in spacecraft launches from initial launch through the first ascent. Many launch vehicles, including the Atlas V, SLS and space shuttle, have used SRBs to gi ...

(SRB) recovery zone. STS-51-D was the third shuttle mission to be extended. On April 19, 1985, 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 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 ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, until the development and implementation of nose wheel steering made landings at KSC more feasible.

Crew

Spacewalk

* '' Hoffman and Griggs '' – EVA 1 * EVA 1 Start: April 16, 1985 * EVA 1 End: April 16, 1985 * Duration: 3 hours, 6 minutes

Crew seating arrangements

Mission summary

During STS-51-D, the shuttle crew deployed two

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 ...

s: Telesat-I ( Anik C1) and

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 (also known as Leasat-3); both were Hughes-built satellites. Telesat-I was attached to a

Payload Assist Module The Payload Assist Module (PAM) is a modular upper stage designed and built by McDonnell Douglas (now Boeing), using Thiokol Star-series solid propellant rocket motors. The PAM was used with the Space Shuttle, Delta, and Titan launchers and carri ...

(PAM-D) motor and successfully deployed.

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

Extra-Vehicular Activity Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA in ...

(EVA) to attach homemade "Flyswatter" devices to the shuttle's 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 ...

). Seddon then engaged the satellite's start lever using the RMS, but again the post-deployment sequence did not begin. The satellite was subsequently retrieved, repaired and successfully redeployed during the

STS-51-I 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 C ...

mission later that year. ''Discovery''s other mission payloads included the Continuous Flow Electrophoresis System III (CFES-III), which was flying for sixth time; two Shuttle Student Involvement Program (SSIP) experiments; the American Flight Echo-cardiograph (AFE); two

Getaway special Getaway Special was a NASA program that offered interested individuals, or groups, opportunities to fly small experiments aboard the Space Shuttle. Over the 20-year history of the program, over 170 individual missions were flown. The program, whi ...

s (GASs); 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 The term micro-g environment (also μg, often referred to by the term microgravity) is more or less synonymous with the terms '' weightlessness'' and ''zero-g'', but emphasising that g-forces are never exactly zero—just very small (on the ...

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.

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 land on the Moon. It was the first J mission, with a longer stay on the Moon and a greater focus on science than ear ...

. 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-D Telesat-1 deployment.jpg, Telesat-I during deployment Image:STS-51-D Syncom IV-3 deployment.jpg, Syncom IV-3 during deployment Image:STS-51-D flyswatter on RMS.jpg, Hoffman and Griggs attach the flyswatter device to the end of the

References

External links

NASA mission summary

{{Orbital launches in 1985 Space Shuttle missions 1985 in spaceflight 1985 in the United States Spacecraft launched in 1985 Spacecraft which reentered in 1985