1971 June 30: crew exposed to vacuum of space : The crew of Soyuz 11, Georgi Dobrovolski, Viktor Patsayev and Vladislav Volkov, were killed after undocking from space station Salyut 1 after a three-week stay. A valve on their spacecraft had accidentally opened when the service module separated, letting their air leak out into space. The capsule reentered and landed normally, and their deaths were only discovered when it was opened by the recovery team. 1971三位太空人因為一個筏門故障導致失壓窒息而死。