After a record-setting 22 day stay about Soviet space station Salyut 1, the crew of Soyuz 11 prepares to return home. As they undock and fire their retro rockets to bring their vehicle out of orbit, Soyuz depressurizes without warning, killing the crew – Georgi Dobrovolski, Vladislav Volkov and Viktor Patsayev – within a minute. (The cramped design of the Soyuz cabin makes no allowances for cosmonauts to wear spacesuits.) Soyuz flights will be grounded for two years until the vehicle can be redesigned to prevent another tragedy. Two members of the grounded prime crew, Alexei Leonov (the first man to walk in space) and Valery Kubasov, are later reassigned to the international Apollo-Soyuz mission in 1975.