Launch from Cape Canaveral (KSC); landing on Edwards AFB. The launch originally set for May 22, 1991. The mission was postponed less than 48 hours before launch when it became known that a leaking liquid hydrogen transducer in orbiter main propulsion system which was removed and replaced during leak testing in 1990, had failed an analysis by vendor. Launch reset for June 1, 1991, but postponed again after several attempts to calibrate inertial measurement unit 2 failed. Unit was replaced and retested, and the launch was rescheduled for June 5, 1991.

It was the fifth dedicated Spacelab mission, Spacelab Life Sciences-1, and first dedicated solely to life sciences, using the habitable module. Mission featured most detailed and interrelated physiological measurements in space since 1973–1974 Skylab missions. Subjects were humans, 30 rodents and thousands of tiny jellyfish. Primary SLS-1 experiments studied six body systems; of 18 investigations, ten involved humans, seven involved rodents, and one used jellyfish. Six body systems investigated were cardiovascular/cardiopulmonary (heart, lungs and blood vessels); renal/endocrine (kidneys and hormone-secreting organs and glands); blood (blood plasma); immune system (white blood cells); musculoskeletal (muscles and bones); and neurovestibular (brains and nerves, eyes and inner ear). Other payloads included twelve Getaway Special (GAS) canisters installed on GAS bridge in cargo bay for experiments In materials science, plant biology and cosmic radiation (see G-616); Middeck Zero-Gravity Dynamics Experiment (MODE); and seven Orbiter Experiments (OEX).

Millie Hughes-Fulford was the first female Payload Specialist.