Crew The six-member crew included Commander Frederick D. Gregory, Pilot Terence T. Henricks, Mission Specialists Story Musgrave, Mario Runco Jr. and James S. Voss, and Payload Specialist Thomas J. Hennen. Gregory flew twice before, and Musgrave flew three times previously. The rest of the crew made their first flight. The IUS booster motor fired as scheduled approximately 12 hours and 32 minutes into the mission, propelling DSP into geosynchronous orbit, and then separated from the satellite about 23 minutes later. DSP satellites detect and report on real-time space liftoffs, missile launches and nuclear detonations.
Infrared sensors detect heat from missile plumes.
Tactical Warning and Attack Assessment System since 1970. Weather conditions obscured some targets for experiments Terra Scout and M88-1. Crew members participated in a series of medical experiments designed to test human performance in space, and readjustment to gravity, for long-duration missions. An exercise treadmill stopped working on Flight Day 3 so crew members, in conjunction with experimenters and the medical community on the ground below, devised an alternate form of exercise to fulfill the experiment requirements. The experiment measures changes in aerobic and anaerobic metabolism during in-flight exercise, by comparison with measurements taken before and after the flight.