Liftoff of shuttle Challenger and mission STS 51-B

51B-S-052 (20 April 1985) --- The STS 51-B Spacelab 3 mission begins with the liftoff of the Challenger from Pad 39A at 12:02 p.m. (EDT). The Spacelab-3 configuration consists of a long module and a Mission Experiment Support Structure (MPESS). The object of the mission is to conduct applications, science and technology-oriented experimentation requiring the low-gravity of Earth orbit and extended duration stable vehicle attitude. Mission emphasis will be on materials processing. The seven-member crew consists of astronauts Robert F Overmyer, commander; Frederick D. Gregory, pilot; Don L. Lind, Norman E. Thagard and William E. Thornton; all mission specialists and payload specialists Taylor G. Wang and Lodewijk van den Berg. The mission is planned for 7 days with a landing at Dryden Flight Research Facility, Edwards California scheduled for May 6.