Cut-away illustration of the Soviet Soyuz 19 spacecraft (upper right) and the US Apollo spacecraft (lower left) docked in Earth orbit during the Apollo Soyuz Test Project (ASTP). At centre Thomas P. Stafford, US crew commander and Aleksey A. Leonov, Soviet crew commander, are shaking hands through the docking adaptor hatch. The ASTP mission was the first joint international crewed space-flight. It took place from 15-24th July 1975. A Soviet Soyuz 19 and American Apollo CSM-111 spacecraft docked in orbit on 17th July to test a jointly-designed international docking mechanism.