... To Fly Free in Space . ... STS-41B , NASA Explanation: At about 100 meters from the cargo bay of the space shuttle Challenger, Bruce McCandless II was farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured above , was floating free in space. McCandless and fellow NASA astronaut Robert Stewart were the first to experience such an "un tether ed space walk " during Space Shuttle mission 41-B in 1984 . ... January . ...