Vladislav Nikolayevich Volkov

Владисла́ Во́лков; 

23 November 1935 – 30 June 1971 

Soviet cosmonaut , who flew on the

Soyuz 7  and Soyuz 11 space missions.

The second mission terminated fatally...

 As an aviation engineer at Korolyov Design Bureau, he was involved in the development of the Vostok and Voskhod spacecraft prior to his selection as a cosmonaut. He flew aboard Soyuz 7 in 1969.

Volkov, on his second space mission in 1971, was assigned to Soyuz 11. 

The three cosmonauts on this flight spent 23 days on Salyut 1, the world's first space station. After three relatively placid weeks in orbit, however, Soyuz 11 became the second Soviet space flight  to terminate fatally, after Soyuz 1

After a normal re-entry , the Soyuz 11 capsule was opened and the corpses of the three crew members were found inside.

 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  causing Volkov and his two flight companions to suffer fatal hypoxia as their cabin descended toward the earth's atmosphere.