Viktor Ivanovich Patsayev (Russian: Виктор Иванович Пацаев; 19 June 1933 – 30 June 1971)[1] was a Soviet cosmonaut who flew on the Soyuz 11 mission and was part of the third space crew to die during a space flight.

[2] 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.

[3] One of Patsayev's hands was found to be bruised, and he may have been trying to shut the valve manually at the time he lost consciousness.

Patsayev's ashes were interred in the Kremlin Wall on Red Square in Moscow.

[5] An account of Patsayev's life and space career appears in the 2003 book Fallen Astronauts: Heroes Who Died Reaching for the Moon by Colin Burgess.