Launch from Cape Canaveral (KSC); landing on Edwards AFB. The launch was delayed 14 minutes by a faulty communication link between KSC and Mission Control in Houston.

The primary payload, the Upper Atmosphere Research Satellite (UARS), was deployed on the third day of the mission. During its planned 18-month mission, the 14,500-pound observatory was to make the most extensive study ever conducted of the Earth's troposphere, the upper level of the planet's envelope of life-sustaining gases which also include the protective ozone layer. UARS had ten sensing and measuring devices: Cryogenic Limb Array Etalon Spectrometer (CLAES); Improved Stratospheric and Mesospheric Sounder (ISAMS); Microwave Limb Sounder (MLS); Halogen Occultation Experiment (HALOE); High Resolution Doppler Imager (HRDI); Wind Imaging Interferometer (WlNDII); Solar Ultraviolet Spectral Irradiance Monitor (SUSIM); Solar/Stellar Irradiance Comparison Experiment (SOLSTICE); Particle Environment Monitor (PEM) and Active Cavity Radiometer Irradiance Monitor (ACRIM II). UARS's initial 18-month mission was extended several times - it was finally retired after 14 years of service.

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.

The crew performed the first Collision Avoidance Maneuver (COLA) to fly in save distance to a Kosmos 955 satellite segment, which had already been launched on September 20, 1977.

Due to bad weather at Cape Canaveral the Discovery was diverted to the Edwards AFB.