STS-53 was a classified Department of Defense mission. No information about the primary payload has been released.
Life sciences experiments performed during the STS-53 mission were those classified as Detailed Supplementary Objectives (DSOs). A DSO is a NASA-sponsored investigation performed by Space Shuttle crewmembers, who serve as the test subjects. These studies are designed to require minimal crew time, power and stowage. Biomedical DSOs focus on operational concerns, including space motion sickness, cardiovascular deconditioning, muscle loss, changes in coordination and balance strategies, radiation exposure, pharmacokinetics and changes in the body's biochemistry.
Additional payloads flown on this mission included multiple Get Away Special (GAS) experiments, including the Orbital Debris Radar Calibration Spheres experiment and the combined Shuttle Glow Experiment/Cryogenic Heat Pipe Experiment; Microcapsules in Space; Space Tissue Loss; Visual Function Tester; Cosmic Radiation Effects and Activation Monitor; Radiation Monitoring Equipment; Fluid Acquisition and Resupply Experiment; Hand-held, Earth-oriented, Real-time, Cooperative, User-friendly, Location-targeting and Environmental System (HERCULES); Battlefield Laser Acquisition Sensor Test; and the Cloud Logic to Optimize Use of Defense Systems (CLOUDS).
Discovery landed at Edwards Air Force Base in California on December 9, 1992, after a successful seven-day mission. Landing was diverted from Kennedy Space Center because of cloud cover.