В 1971 году Советский Союз вывел на орбиту первую в мире космическую станцию «Салют»

On June 6 of the same year spacecraft Soyuz-11 with Georgy Dobrovolsky, Vladislav Volkov and Viktor Patsayev on board performed the flight to the orbital station. While they were coming back to the Earth on June 30, one of the valves got wrong, which led to cabin pressure failure. The names of three more cosmonauts joined the mournful list of space flight victims started by Vladimir Komarov in 1967.