The primary payload of this mission was the Space Radar Laboratory, activated by crew and operated by teams on ground. SRL-1 included the Spaceborne Imaging Radar-C and the X-band Synthetic Aperture Radar (X-SAR) and an atmospheric instrument called Measurement of Air Pollution from Satellites (MAPS). The German Space Agency (DARA) and the Italian Space Agency (ASI) provided the X-SAR instrument. Thirteen countries were represented in the project with 49 principal investigators and more than 100 scientists, coordinated by the Jet Propulsion Laboratory. Some 133 hours of data were collected. The MAPS experiment measured the global distribution of carbon monoxide in the troposphere, or lower atmosphere.
Life sciences payloads on this mission included a study called NIH.C1, which was a collaborative effort between NASA and the National Institutes of Health (NIH). Experiments in this payload were performed to determine the effects of microgravity on the growth rate, protein production and differentiation of bone cells. Also studied was how muscle cells flown in space mature after return to Earth. This research will help investigators understand what is happening at the cellular level to astronauts who suffer from bone loss and muscle deterioration in space flight, as well as understanding the mechanisms involved in bone loss and muscle atrophy on Earth.
Other life sciences experiments performed during the STS-59 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.
Other payloads on this mission were the Get-Away Special (GAS) experiments, Consortium for Materials Development in Space Complex Autonomous Payload-IV (CONCAP IV), Visual Function Tester-4, and Shuttle Amateur Radio Experiment. This mission also marked the first flight of the Toughened Uni-Piece Fibrous Insulation, known as TUFI, an improved thermal protection tile. Several test tiles were placed on the Shuttle's base heat shield between three main engines.
The landing of the Space Shuttle Endeavour was originally planned for Kennedy Space Center on April 19, 1994. However, due to low clouds and possible thunderstorms in the area, the Space Shuttle Endeavour landed at Edwards Air Force Base in California on April 20, 1994.