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 11 involved separating "Columbia" from the spent S-IVB stage, turning around, and docking with "Eagle" still attached to the stage. After the LM was extracted, the combined spacecraft headed for the Moon, while the rocket stage flew on a trajectory past the Moon. This was done to avoid colliding with the spacecraft, the Earth, or the Moon. A slingshot effect from passing around the Moon threw it into an orbit around the Sun. On July 19 at 17:21:50 UTC, Apollo 11 passed behind the Moon and fired its service propulsion engine to enter lunar orbit. In the thirty orbits that followed,