The Apollo-Soyuz (ASTP) programme saw the first time spacecraft from the two nations rendezvoused and docked in orbit. The idea for this had been initiated three years earlier with an agreement signed by US President Nixon and Soviet President Kosygin.

The US crew was commanded by Tom Stafford accompanied by two rookies, Vance Brand and Deke Slayton, who following his grounding due to heart problems had been restored to flight status. The Soyuz was commanded by veteran Alexei Leonov accompanied by Valery Kubasov.