STS-51B

STS-51B was the seventeenth Space Shuttle mission, Challenger's seventh flight, and the first fully operational mission for the European-built Spacelab module. NASA identifies the mission as Spacelab 3, a multidisciplinary laboratory flight focused on microgravity science, atmospheric and solar observations, materials processing, life sciences, and medical monitoring. The crew worked in shifts so Spacelab operations could continue around the clock. Challenger launched from Kennedy Space Center's Launch Complex 39A on April 29, 1985, with Robert Overmyer commanding and Frederick Gregory serving as pilot. Don Lind, Norman Thagard, and William Thornton flew as mission specialists, while Lodewijk van den Berg and Taylor Wang flew as payload specialists. Van den Berg supported crystal-growth research, and Wang served as principal investigator for the Drop Dynamics Module experiment. The mission landed at Edwards Air Force Base on May 6 after 7 days, 0 hours, 8 minutes, and 46 seconds in orbit. Adding STS-51B completes Frederick Gregory's remaining known Shuttle flight link and adds the production records needed for Lind, Van den Berg, and Wang.