Soyuz 11

Soyuz 11 succeeded in completing the mission that Soyuz 10 had failed at - carrying cosmonauts to live on the world's first space station, Salyut 1.

Cosmonauts Georgi Dobrovolski, Viktor Patsayev, and Vladislav Volkov spent three weeks testing the Salyut's systems and conducting biomedical and other scientific work. They faced a number of difficulties on the station, including a fire, and the discovery that one of the station's main scientific instruments - a telescope - had been rendered inoperative by a protective cover that had failed to detach after launch. For these reasons, the mission was cut short by a week and the crew departed the station. Tragedy struck shortly afterwards.

After a normal re-entry, the recovery team opened the capsule to find the crew dead. It quickly became apparent that they had asphyxiated, and the fault was traced to a valve that had been jolted open as the spacecraft undocked. The valve was supposed to equalise pressure inside the capsule in the final moments before landing, but in this case had instead allowed the cosmonauts' air to leak away into space.

They were given a large state funeral. US astronaut Tom Stafford was one of the pallbearers.

The Soyuz spacecraft was extensively re-designed after this incident to carry only two cosmonauts. The extra room meant that the crew could wear space suits during launch and landing.

Crew

• Georgi Dobrovolski
• Viktor Patsayev
• Vladislav Volkov