STS-6

STS-6 was the sixth NASA Space Shuttle mission and the maiden flight of the Space Shuttle Challenger. Launched from Kennedy Space Center on 4 April 1983, the mission deployed the first Tracking and Data Relay Satellite, TDRS-1, into orbit, before landing at Edwards Air Force Base on 9 April. STS-6 was the first Space Shuttle mission during which a spacewalk was conducted, and hence was the first in which the Extravehicular Mobility Unit (EMU) was used.

Crew
STS-6 was the last shuttle mission with a four-person crew until STS-135, the final shuttle mission, which launched on 8 July 2011. Commander Paul Weitz had previously served as Pilot on the first Skylab mission, where he lived and worked in Skylab for nearly a month from May to June 1973. After Skylab, Weitz became the Deputy Chief of the Astronaut Office under Chief Astronaut John Young. Bobko originally became an astronaut for the Air Force's Manned Orbiting Laboratory program but later joined NASA in 1969 after the MOL program's cancellation. Prior to STS-6 he participated in the Skylab Medical Experiment Altitude Test and worked as a member of the support crew for the Apollo-Soyuz Test Project.

Peterson was also a transfer from the MOL program, and was a member of the support crew for Apollo 16. Musgrave joined NASA in 1967 as part of the second scientist-astronaut group, and was the backup Science Pilot for the first Skylab mission. He also participated in the design of the equipment that he and Peterson used during their EVA on the STS-6 mission.

Support crew

 * Roy D. Bridges Jr. (entry CAPCOM)
 * Mary L. Cleave
 * Richard O. Covey (ascent CAPCOM)
 * Guy S. Gardner
 * Jon A. McBride
 * Bryan D. O'Connor

Spacewalks

 *  Musgrave and Peterson 
 * EVA Start: 7 April 1983
 * EVA End: 8 April 1983
 * Duration: 4 hours, 17 minutes

Mission background
The mission was originally scheduled to launch on 20 January 1983. However, a hydrogen leak in one of the orbiter's main engines was discovered after the first flight readiness firing in December 1982. Later, after a second flight readiness firing of the main engines on 25 January 1983, fuel line cracks were found in the other two engines. A spare engine replaced the engine with the hydrogen leak, and the other two engines were removed, repaired and reinstalled. It was also the first time a shuttle other than Columbia was used in an orbital flight.

While the engine repairs were underway on 28 February, a severe storm caused contamination of the mission's primary cargo, the first Tracking and Data Relay Satellite, TDRS-1, while it was in the Payload Change-out Room on the Rotating Service Structure at the launch pad. Consequently, the satellite had to be taken back to its checkout facility, where it was cleaned and rechecked. The Payload Change-out Room and the payload bay also had to be cleaned. All of these events pushed the launch back from 26 March to early April.

Mission summary
On 4 April 1983, STS-6, the first mission of the orbiter Challenger, lifted off at 13:30 EST. It marked the first use of a new lightweight external tank and lightweight SRB casings.

STS-6 carried a crew of four – Paul J. Weitz, commander; Karol J. Bobko, pilot; Story Musgrave and Donald H. Peterson, both mission specialists. Using new spacesuits designed specifically for the Space Shuttle program, Musgrave and Peterson successfully accomplished the program's first extravehicular activity (EVA) on 7–8 April 1983, performing various tests in the orbiter's payload bay. Their spacewalk lasted 4 hours and 17 minutes.

Although the 5000 lbs TDRS satellite was successfully deployed from Challenger, its two-stage booster rocket, the Inertial Upper Stage (IUS), tumbled out of control, placing the satellite into a low elliptical orbit. However, the satellite contained extra propellant beyond what was needed for its attitude control thrusters, and during the next several months, its thrusters were fired at carefully planned intervals, gradually moving TDRS-1 into its geosynchronous operating orbit, thus saving the $100-million satellite. Other STS-6 payloads included three GAS canisters and the continuation of the Mono-disperse Latex Reactor and Continuous Flow Electrophoresis experiments.

Challenger returned to Earth on 9 April 1983 at 10:53 am PST, landing on Runway 22 at Edwards Air Force Base. During the mission, it completed 80 orbits, traveling 2 million miles in 5 days, 23 minutes and 42 seconds. It was flown back to KSC on 16 April 1983.

Mission insignia
The six white stars in the upper blue field of the mission patch indicate the flight's numerical designation in the Space Transportation System's mission sequence.

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.