The primary objectives during this mission were the deployment of the European Space Agency's European Retrievable Carrier (EURECA) and operation of the joint NASA/Italian Space Agency Tethered Satellite System (TSS). Research on EURECA was primarily devoted experiments in the fields of material sciences, life sciences and radiobiology. After 11 months in orbit, the Shuttle Endeavour (STS-57) retrieved the science satellite. The TSS was to provide a new capability for probing the space environment and conducting experiments. The reusable satellite consisted of a strong cord reeled into space from the Shuttle's cargo bay. When deployed, the TSS was to be the longest structure ever flown in space.
EURECA was deployed one day later than scheduled because of problems in its data handling system. As a result of this delay, the TSS deployment was also delayed. Another problem arose when the tether line of the TSS jammed after being deployment at 800 feet, far less than the 12.5 mile goal. After several attempts to free the tether, TSS operations were curtailed and the satellite was stowed for return to Earth.
Life sciences payloads on this mission included a study of the Pituitary Growth Hormone Cell Function (PHCF), an experiment designed to evaluate the activity of rat pituitary cells in microgravity. Results from previous experiments have shown that rat pituitary cells release less hormone during space flight than on the ground. The PHCF experiment was performed on cultured rat pituitary cells to determine if microgravity affects the cell's capacity to produce biologically or immunologically active growth hormone (GH), and whether any alterations in pituitary hormone secretion remain in vitro after return to Earth. This experiment was also designed to study the effects of microgravity on the GH-producing cell population.
Other life sciences experiments performed during the STS-46 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 on this mission included the Evaluation of Oxygen Integration with Materials/Thermal Management Processes, Consortium for Materials Development in Space Complex Autonomous Payload (CONCAP II and CONCAP III), IMAX Cargo Bay Camera, Limited Duration Space Environment Candidate Materials Exposure, Air Force Maui Optical Site (AMOS) calibration experiment, and the Ultraviolet Plume Instrument.
After the mission's one day extension, the crew returned to Kennedy Space Center in Florida on August 8, 1992.