A period of détente followed with the April 1972 agreement on a co-operative Apollo–Soyuz Test Project (ASTP), resulting in the July 1975 rendezvous in Earth orbit of a US astronaut crew with a Soviet cosmonaut crew and joint development of an international docking standard APAS-75. Apollo–Soyuz began a period of transition from the Space Race to an age of US / Russian space cooperation by December 1991, when the dissolution of the Soviet Union brought the end of the Cold War and enabled the Shuttle–"Mir" and International Space Station programs between the US and the newly founded Russian Federation.