STS-41B - MMU - Spacewalkers

On the fourth day of the STS-41B mission, astronauts McCandless and Stewart performed the first untethered spacewalk, operating the Manned Maneuvering Unit (MMU) for the first time. McCandless, the first human Earth-orbiting satellite, 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. On the seventh day of the mission, both astronauts performed an EVA to practice capture procedures for the Solar Maximum Mission satellite retrieval and repair operation, which was planned for the next mission, STS-41-C.