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.