Soyuz 11 - Death of Crew

Death of Crew

On June 30, 1971, after an apparently normal re-entry of the capsule of the Soyuz 11 mission, the recovery team opened the capsule to find the crew dead. It quickly became apparent that they had been asphyxiated. The fault was traced to a breathing ventilation valve, located between the orbital module and the descent module, that had been jolted open as the descent module separated from the service module, 723 seconds after retrofire. The two were held together by explosive bolts designed to fire sequentially; in fact, they fired simultaneously. The force of this caused the internal mechanism of the pressure equalization valve to loosen a seal that was usually discarded later and normally allowed automatic adjustment of the cabin pressure. The valve opened at an altitude of 168 kilometers (104 mi), and the gradual loss of pressure was fatal within seconds. The valve was located beneath the seats and was impossible to find and block before the air was lost. Flight recorder data from the single cosmonaut outfitted with biomedical sensors showed cardiac arrest occurred within 40 seconds of pressure loss. By 935 seconds after the retrofire, the cabin pressure was zero, and remained there until the capsule hit the Earth's atmosphere.

Film later declassified showed support crews attempting CPR on the cosmonauts. It was not known until an autopsy that they had died because of a capsule depressurization. The ground crew had lost audio contact with the crew before re-entry began and had already begun preparations for contingencies in case the crew had been lost.

The cosmonauts were given a large state funeral and buried in the Kremlin Wall Necropolis at Red Square, Moscow near the remains of Yuri Gagarin. U.S. astronaut Tom Stafford was one of the pallbearers. They were also each posthumously awarded the Hero of the Soviet Union medal. Craters on the Moon were named after the three cosmonauts.

The Soyuz 11 landing coordinates are 47°21′24″N 70°07′17″E / 47.35663°N 70.12142°E / 47.35663; 70.12142 which is 90 km south-west of Karazhal, Karagandy, Kazakhstan and about 550 km north-east of Baikonur. At the site is a memorial monument in the form of a three-sided metallic column. Near the top of the column, on each of the three sides, is the engraved image of the face of each crew member set into a stylized triangle. The memorial is in open, flat country, far from any populated area. It is within a small, circular, fenced area.

The Soyuz spacecraft was extensively redesigned after this incident to carry only two cosmonauts. The extra room meant that the crew could wear space suits during launch and landing. A Soyuz capsule would not hold three crew members again until the Soyuz-T redesign in 1980, which freed enough space for three people in lightweight pressure suits to travel in the capsule.