STS-48 was a Space Shuttle mission that launched on 12 September 1991, from Kennedy Space Center, Florida. The orbiter was Space Shuttle Discovery. The primary payload was the Upper Atmosphere Research Satellite (UARS). The mission landed on 18 September at 12:38 am at Edwards Air Force Base on runway 22. The mission was completed in 81 revolutions of the Earth and traveled 2.2 million miles. The 5 astronauts carried out a number of experiments and deployed several satellites.
Secondary payloads were: Ascent Particle Monitor (APM); Middeck 0-Gravity Dynamics Experiment (MODE); Shuttle Activation Monitor (SAM); Cosmic Ray Effects and Activation Monitor (CREAM); Physiological and Anatomical Rodent Experiment (PARE); Protein Crystal Growth II-2 (PCG II-2); Investigations into Polymer Membrane Processing (IPMP); and the Air Force Maui Optical Site (AMOS) experiment.