STS-41-B

Two communications satellites were deployed about 8 hours after launch; one, Westar 6, was for America's Western Union, and the other, Palapa B2, for Indonesia. On the fourth day of the mission, astronauts McCandless and Stewart performed the first untethered spacewalk, operating the Manned Maneuvering Unit (MMU) for the first time. McCandless ventured out 320 feet (98 m) from the orbiter, while Stewart tested the "work station" foot restraint at the end of the Remote Manipulator System.