Soyuz 1 dooms cosmonaut: The first fatal accident in a space mission befell Soviet cosmonaut Vladimir Komarov, whose problem-plagued Soyuz 1 capsule crashed onto Russian soil in 1967.
'Gravity' and Reality: History's Worst Space Disasters
Deaths in space: The Soviet space program also suffered the first, and so-far only, deaths in space in 1971, when cosmonauts Georgi Dobrovolski, Viktor Patsayev, Vladislav Volkov died while returning to Earth from the Salyut 1 space station. Their Soyuz 11 craft performed a textbook-perfect landing in 1971. So recovery teams were appalled to find the three-man crew sitting dead in their couches, with dark-blue splotches on their faces and blood dripping from their ears and noses.
An investigation showed that a breathing ventilation valve had ruptured, asphyxiating the cosmonauts. The resulting drop in pressure also exposed the crew to the vacuum of space ? the only human beings to ever experience such a fate