This is a model of the Project Orion spacecraft powered by successive explosions of hydrogen atomic bombs. The nuclear explosion pulse concept was conceived by Stanislaw M. Ulam. The crew compartment was to be well shielded from the blast and radiation. Shocks were absorbed through water-cooled springs behind the pusher plate.
In 1958, the Advanced Research Project Agency (ARPA) granted a study of the concept to the General Dynamics Corporation. However, after seven years of work, Orion was canceled in 1964 mainly because of the Nuclear Test Ban Treaty of 1963, which outlawed nuclear testing in the atmosphere. This object was donated to the Smithsonian in 1979 by the General Dynamics Corp.