Apollo–Soyuz Test Project made the Soviet Union's policy of détente official in his 1956 doctrine of peaceful coexistence at the 20th Congress of the Communist Party of the Soviet Union, the two nations seemed to be in perpetual conflict. Due to tense relations, space cooperation between the United States and the Soviet Union was unlikely in the early 1970s. On June 7, 1971, the USSR had launched the first piloted orbital space station, Salyut 1. Meanwhile, the United States had launched the Apollo 14 mission several months prior, the third spacecraft to land humans on the moon. Each side gave the other little
Docking and berthing of spacecraft The Apollo program depended on lunar orbit rendezvous to achieve its objective of landing men on the Moon. This required first a transposition, docking, and extraction maneuver between the Apollo Command/Service Module (CSM) mother spacecraft and the Lunar Module (LM) landing spacecraft, shortly after both craft were sent out of Earth orbit on a path to the Moon. Then after completing the lunar landing mission, two astronauts in the LM had to rendezvous and dock with the CSM in lunar orbit, in order to be able to return to Earth. The spacecraft were designed to permit intra-vehicular crew transfer through