The Project would send NASA astronauts Tom Stafford, Deke Slayton and Vance Brand in an Apollo Command and Service Module to meet Russian cosmonauts Aleksey Leonov and Valeriy Kubasov in a Soyuz capsule.
The Apollo-Soyuz Test Project was the first spaceflight to include two participating nations working together with their own national spacecraft.
The Soyuz and Apollo spacecraft docked on July 17, 1975, in a demonstration of how well the rendezvous and docking systems of each spacecraft would work with each other. The combined crew of five people (three Americans, two Soviets) spent about two days in orbit working on experiments and conducting joint press conferences.
The men’s activities in orbit drew praise from both nations, including a Soviet radio announcer who proclaimed Apollo-Soyuz Test Project “a forerunner of future international orbital stations,” according to NASA.