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 17 19, the crew jettisoned the no-longer-needed SM, leaving only the CM for return to Earth. The Apollo 17 spacecraft reentered Earth's atmosphere and landed safely in the Pacific Ocean at 2:25 pm, from the recovery ship, . Cernan, Evans, and Schmitt were then retrieved by a recovery helicopter and were safely aboard the recovery ship 52 minutes after landing. The command module "America" is currently on display at Space Center Houston at the Lyndon B. Johnson Space Center in Houston, Texas. The ascent stage of lunar module "Challenger" impacted the Moon December 15, 1972 at 06:50:20.8 UT (1:50 am EST),