Soyuz 1

Soyuz 1 (Russian: Союз 1, Union 1) was a crewed spaceflight of the Soviet space program. Launched into orbit on 23 April 1967 carrying cosmonaut colonel Vladimir Komarov, Soyuz 1 was the first crewed flight of the Soyuz spacecraft. The flight was plagued with technical issues, and Komarov was killed when the descent module crashed into the ground due to a parachute failure. This was the first in-flight fatality in the history of spaceflight.

The original mission plan was complex, involving a rendezvous with Soyuz 2 and an exchange of crew members before returning to Earth. However, the launch of Soyuz 2 was called off due to thunderstorms.

Soyuz 1 was the first crewed flight of the first-generation Soyuz 7K-OK spacecraft and Soyuz rocket, designed as part of the Soviet lunar program. It was the first Soviet crewed spaceflight in over two years, and the first Soviet crewed flight following the death of the Chief Designer of the space programme Sergei Korolev. Komarov was launched on Soyuz 1 despite failures of the previous uncrewed tests of the 7K-OK, Kosmos 133 and Kosmos 140. A third attempted test flight was a launch failure; a launch abort triggered a malfunction of the launch escape system, causing the rocket to explode on the pad. The escape system successfully pulled the spacecraft to safety.

According to interviews with Venyamin Russayev, a former KGB agent, prior to launch, Soyuz 1 engineers are said to have reported 203 design faults to party leaders, but their concerns "were overruled by political pressures for a series of space feats to mark the anniversary of Lenin's birthday". Russayev also claims that Yuri Gagarin was the backup pilot for Soyuz 1, and was aware of the design problems and the pressures from the Politburo to proceed with the flight. He attempted to "bump" Komarov from the mission, knowing that the Soviet leadership would not risk a national hero on the flight. At the same time, Komarov refused to pass on the mission, even though he believed it to be doomed. He explained that he could not risk Gagarin's life. Russayev's account, however, has been seen as implausible and exaggerated by most historians of the Soviet space programme.

Mission planners intended to launch a second Soyuz flight the next day carrying cosmonauts Valery Bykovsky, Yevgeny Khrunov, and Aleksei Yeliseyev, with Khrunov and Yeliseyev scheduled to do an EVA over to Soyuz 1.

Soyuz 1 was launched on 23 April 1967 at 00:32 GMT from Baikonur Cosmodrome carrying Komarov, the first Soviet cosmonaut to fly in space twice, in the 7K-OK No. 4 capsule. Problems began shortly after launch when one solar panel failed to unfold, leading to a shortage of power for the spacecraft's systems. Komarov transmitted: "Conditions are poor. The cabin parameters are normal, but the left solar panel didn't deploy. The electrical bus is at only 13 to 14 amperes. The HF (high frequency) communications are not working. I cannot orient the spacecraft to the sun. I tried orienting the spacecraft manually using the DO-1 orientation engines, but the pressure remaining on the DO-1 has gone down to 180." Further problems with the orientation detectors complicated maneuvering the craft. By orbit 13, the automatic stabilisation system was completely dead, and the manual system was only partially effective.

The crew of Soyuz 2 modified their mission goals, preparing themselves for a launch that would include fixing the solar panel of Soyuz 1. However, that night, thunderstorms at Baikonur affected the booster's electrical system, causing the mission to be called off.

As a result of Komarov's report during the 13th orbit, the flight director decided to abort the mission. After 18 orbits, Soyuz 1 fired its retrorockets and reentered the Earth's atmosphere. Despite the technical difficulties up to that point, Komarov might still have landed safely. A few minutes before the tragedy, Komarov maintained radio contact with Gagarin, in particular, stating: "The engine was running for 146 seconds. Everything is going fine. Everything is going fine! The ship was oriented correctly. I am in the middle chair. Tied with straps." To slow the descent, first the drogue parachute was deployed, followed by the main parachute. However, due to a defect, the main parachute did not unfold; the exact reason for the main parachute malfunction is disputed.