List of spaceflight-related accidents and incidents in the context of "Space Shuttle Challenger disaster"

Human error is an action that has been done but that was "not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits". Human error has been cited as a primary cause and contributing factor in disasters and accidents in industries as diverse as nuclear power (e.g., the Three Mile Island accident), aviation, space exploration (e.g., the Space Shuttle Challenger disaster and Space Shuttle Columbia disaster), and medicine. Prevention of human error is generally seen as a major contributor to reliability and safety of (complex) systems. Human error is one of the many contributing causes of risk events.

Soyuz 11 (Russian: Союз 11, lit. 'Union 11') was the only crewed mission to board the world's first space station, Salyut 1. The crew, Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, arrived at the space station on 7 June 1971, and departed on 29 June 1971. The mission ended in disaster when the crew capsule depressurised during preparations for re-entry, killing the three-person crew. The three crew members of Soyuz 11 are the only humans to have died in space.

Vladislav Nikolayevich Volkov (Russian: Владислав Николаевич Волков; 23 November 1935 – 30 June 1971) was a Soviet cosmonaut who flew on the Soyuz 7 and Soyuz 11 missions. The second mission terminated fatally. Volkov and the two other crew members were asphyxiated on reentry, the only three people to have died in outer space.

Viktor Ivanovich Patsayev (Russian: Виктор Иванович Пацаев; 19 June 1933 – 30 June 1971) 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. On board the space station Salyut 1 he operated the Orion 1 Space Observatory (see Orion 1 and Orion 2 Space Observatories); he became the first man to operate a telescope outside the Earth's atmosphere.

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. 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.