On this day in 1971, three Russian cosmonauts were found dead in their space capsule after it made what looked like a perfect landing in Kazakhstan. Lieutenant-Colonel George Dobrovolsky, Vladislav Volkov and Viktor Patsayev were found dead in their seats on the Soyuz 11 but did not appear to have suffered any physical injuries.
The Soviet Government ordered an immediate inquiry into the tragedy. It was thought the most likely cause was oxygen failure on re-entry into the atmosphere or unknown side-effects of their lengthy stay in space. The crew had spent a record 24 days in space, the longest period anyone had remained weightless and experts thought this could have been linked to their death.
The cosmonauts had become the first men to stay at a space station when they docked with the Soviet Salyut 1. They were conducting scientific experiments and observations during their trip which started when they launched on 6 June.
Following an inquiry into the accident it was concluded the three cosmonauts on the Soyuz 11 were killed by a fatal rise in blood pressure caused when the cabin became depressurised.
The first man to die in space was Vladimir Komarov, in 1967, when the parachute on his Soyuz 1 developed trouble on landing.
