STS-51

STS-51 was a Space Shuttle Discovery mission that launched the Advanced Communications Technology Satellite (ACTS) in September 1993. The flight also featured the deployment and retrieval of the SPAS-ORFEUS satellite and its IMAX camera, which captured spectacular footage of Discovery in space. A spacewalk was also performed during the mission to evaluate tools and techniques for the STS-61 Hubble Space Telescope servicing mission later that year. STS-51 was the first shuttle mission to fly a GPS receiver, a Trimble TANS Quadrex. It was mounted in an overhead window where limited field of view and signal attenuation from the glass severely impacted receiver performance. (Full triple-redundant 3-string GPS would not happen until 14 years later with STS-118.)

Crew

Spacewalks

Launch Preparations

STS-51 was notable for having been scrubbed three times on the launchpad, each time after the crew had boarded the spacecraft:

STS-51 (disambiguation)

NASA flew a number of Space Shuttle missions in the early and mid-1980s with designations derived from STS-51. Most occurred in 1985.

The ambiguity was the result of a NASA decision to change designation of missions starting in Fiscal Year 1984. Previously, missions were designated in the order they were flown (i.e., STS-9 indicated the ninth shuttle mission). The new designation was designed to accommodate a dramatically increased launch manifest, address the addition of a west coast launch site and to resolve confusion from manifested missions not being flown in order due to delays. The new designation used a three-part designator following the term "STS". The first number represents the fiscal year of the launch, the second represents the launch location (1=Florida, 2=California) and the alphanumeric code represents the order launched (i.e., A is first, B is second, etc.). Therefore, the first mission using this designation, which was the tenth shuttle mission was STS 41B. It launched in FY 1984, from Florida and was the first to launch in that year.

STS-51-J

STS-51-J was the 21st NASA Space Shuttle mission and the first flight of Space Shuttle Atlantis. It launched from Kennedy Space Center, Florida, on 3 October 1985, carrying a payload for the U.S. Department of Defense, and landed at Edwards Air Force Base, California, on 7 October.

Crew

Backup crew

Crew notes

Before William Pailes was assigned to the STS-51-J flight, Richard M. Mullane was rumored to have been assigned as Mission Specialist 3 on his second trip to space.

Mission summary

STS-51-J launched on 3 October 1985, at 11:15 EDT, from Launch Pad 39A at the Kennedy Space Center. The launch was delayed by 22 minutes and 30 seconds due to a problem with a main engine liquid hydrogen prevalve close remote power controller; the controller was showing a faulty "on" indication.

The mission was the second shuttle flight totally dedicated to deploying a Department of Defense payload, after STS-51-C. Its cargo was classified, but it was reported that two (USA-11 and USA-12) DSCS-III (Defense Satellite Communications System) satellites were launched into stationary orbits by an Inertial Upper Stage. The DSCS satellites used X-band frequencies (8/7 GHz). Each DSCS-III satellite had a design life of ten years, although several of the DSCS satellites have far exceeded their design life expectancy.