This is a model of Spacelab, a modular laboratory system installed in the payload bay of the Space Shuttle orbiter. During Spacelab missions in the 1980s and 1990s, the Shuttle became an intermittent space station for research conducted by scientists and astronauts. The laboratory module where the crew worked on experiments was a pressurized cylindrical room connected to the crew cabin by a tunnel. The pallet was a platform or "porch" for telescopes, cameras, and other instruments that needed to be outside in space. About 40 Spacelab missions were flown on the Shuttle from 1983-1998. The European developers of Spacelab gave this model to the Museum in 1980 before Spacelab had flown in space.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.