This is an on-board guidance computer designed and built for Project Gemini. This computer was flown on the second Gemini mission, which tested the basic spacecraft configuration in a brief, unmanned suborbital flight in January, 1965.
Gemini computers were digital, real-time, solid state computers, which provided on-board guidance, navigation, and control, especially to assist the astronauts in the rendezvous with other space craft in Earth orbit. They were built for NASA by the Federal Systems Division of IBM, located in Owego, New York.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.