The meeting of the American "Apollo" and the Soviet "Soyuz" on July 19, 1975, marked the first cooperative space mission between the United States and the Soviet Union.
In 1972 US President Nixon and Soviet Premier Alexei Kosygin signed an agreement that included space cooperation. Thus developed the idea of a joint Apollo Soyuz mission. NASA and Soviet Space Authority worked together to develop a mission. It was difficult to meld the two very different cultures of the two groups. NASA gave its astronauts much more control of the spacecraft than the Soviets did, in addition, NASA had multiple backup systems while the Russians aborted a mission if there was a problem. The engineers on both sides developed a docking system that could work either automatically or manually
The Americans used a Saturn 1B rocket to launch an Apollo capsule with three astronauts Tom Stafford, Vance Brand, and Deke Slayton. The Soviets sent a two-person crew in a Soyuz capsule carrying Alexey Leonov and Valeri Kubasov. Both spacecraft launched on July 15, 1975, seven hours apart. Two days later the two spacecraft docked. For 44 hour the two crews conducted experiments together. After separating the Soyuz remained in space for two more days while the Apollo spacecraft remained in orbit for five days. The mission was considered a success by all sides.