This oxidizer tank is from cylindrical Reaction Control System section of Gemini VI-A. It supplied nitrogen tetroxide to the RCS thrusters. Walter M. "Wally" Schirra commanded Gemini VI-A and Thomas P. "Tom" Stafford was the pilot. Gemini VI was originally scheduled to rendezvous and dock with an Agena target vehicle in October 1965, but after that vehicle was destroyed during launch, the mission was renumbered VI-A and changed to a rendezvous with Gemini VII. Gemini VI-A was launched on December 15, 1965, eleven days after Gemini VII, which acted as the rendezvous target. Three orbits after its launch, Gemini VI-A approached to within 6 inches of Gemini VII, the first rendezvous in space history.
The tank likely was flown on Gemini VI-A and replaced afterward during refurbishment for display. NASA transferred the spacecraft and components to the Smithsonian in 1968.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.