This stamp pictures the crew of the July 1975 Apollo-Soyuz Test Project (ASTP). During that mission Amercan astronauts Thomas Stafford, Vance Brand, and Deke Slayton, docked their Apollo spacecraft with the Soviet Soyuz craft that carried Aleksei Leonov and Valeri Kubasov. ASTP was the first joint international human spaceflight mission. There was not another one similar for nearly 20 years. The 50 kopek stamp features a group portrait of the American and Soviet crews as par of the frame which also includes autographs of all the participants. The actual stamp includes a drawing of the Soviet mission control center outside Moscow.
Staff of the USSR Embassy in Washington, D.C. presented this stamp to the museum in1978.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.