10th Space Shuttle Mission

4th Flight of Challenger Crew:

Vance D. Brand, Commander

Robert L. Gibson, Pilot

Bruce McCandless II, Mission Specialist

Ronald E. McNair, Mission Specialist

Robert L. Stewart, Mission Specialist

The mission featured the first untethered spacewalks, which were performed by astronauts McCandless and Stewart using Manned Maneuvering Units (MMU). WESTAR-VI and PALAPA-B2 satellites were deployed, but failure of the PAM-D rocket motors left them in improper low-earth orbits.