Vladislav Volkov
Vladislav Nikolayevich Volkov (Russian: Владислав Николаевич Волков; born November 23, 1935, Moscow – June 30, 1971) was a Soviet cosmonaut who flew on the Soyuz 7 and Soyuz 11 missions.
He had the unfortunate distinction of being part of the second crew to die during a space flight on Soyuz 11.
After a normal re-entry, the capsule was opened and the crew was found dead. It was discovered that a valve had opened just prior to leaving orbit that had allowed the capsule's atmosphere to vent away into space, suffocating the crew. en:Wladislaw Nikolajewitsch Wolkow