The Mobile Service Structure moves away from the Skylab 4 space vehicle the night before the launch. Skylab 4 launched on Nov. 16, 1973. The crew - Commander Gerald Carr, Mission Pilot William Pogue and Edward Gibson - spent 84 days aboard the station. Image credit: NASA. 

The Mobile Service Structure moves away from the Skylab 4 space vehicle the night before the launch. Skylab 4 launched on Nov. 16, 1973. The crew - Commander Gerald Carr, Mission Pilot William Pogue and Edward Gibson - spent 84 days aboard the station. Image credit: NASA