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 15 postal covers incident about ; they entered the spacecraft in Scott's pocket. Apollo 15 blasted off for the Moon at 9:34 am on July 26, 1971, with three astronauts and about 641 covers aboard. At some point while the mission was en route to the Moon, the 400 covers were moved into the lunar lander "Falcon"; in his testimony, Scott agreed this violated the rules. He stated he did not recall how the transfer took place, and that he was only certain that the envelopes went to the lunar surface because they were in the bag of items taken out of the "Falcon"