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
Apollo (spacecraft) 17 it also carried a scientific instrument package, with a mapping camera and a small sub-satellite to study the Moon. A major portion of the service module was taken up by propellant and the main rocket engine. Capable of multiple restarts, this engine placed the Apollo spacecraft into and out of lunar orbit, and was used for mid-course corrections between the Earth and the Moon. The service module remained attached to the command module throughout the mission. It was jettisoned just prior to reentry into the Earth's atmosphere. The lunar module was a separate vehicle designed to land on the