This is a 1:20 scale model of the complete Skylab space station launched by the United States in 1973 and occupied by three crews in 1973-1974. The Skylab living quarters, or orbital workshop, were a converted third stage of a Saturn V rocket. Skylab included a large solar observatory with four solar panels, and docking and airlock modules. NASA gave this model to the Museum in 1972, before the mission, and it has long been displayed near the full-size backup Skylab orbital workshop.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.