ASTP

ASTP, the Apollo-Soyuz Test Project, was the first joint spaceflight undertaken by the United States and the Soviet Union. Conducted in July 1975, it demonstrated technical and administrative cooperation during space operations by docking an American Apollo spacecraft with a Soviet Soyuz in Earth orbit. The mission used an Apollo spacecraft and the Soviet Soyuz 19 spacecraft, connected in orbit with the APAS-75 docking system.

The NASA crew consisted of Thomas P. Stafford (Commander), Vance D. Brand (Command Module Pilot), and Donald K. Slayton (Pilot). The Soviet crew was Alexei Leonov (Commander) and Valeri Kubasov (Flight Engineer). A notable moment of the mission was the first handshake in space between an American and a Soviet astronaut after docking, signaling a thaw in Cold War tensions and serving as a symbol of international cooperation.

During the docked phase, the two spacecraft conducted joint operations, including life sciences and materials experiments, and practiced procedures for international crewed operations. The two spacecraft remained docked for about two days before undocking. The Apollo returned to Earth and splashed down in the Pacific Ocean, while the Soyuz 19 lander returned separately to the Soviet Union.

ASTP's significance lies in its demonstration of cooperative spaceflight practices and interoperability between two space programs. It provided valuable experience for future international collaborations in human spaceflight and helped establish a framework for subsequent multinational missions.