The first was on April 24, 1967 when Soviet cosmonaut Vladimir Komarov was killed on board Soyuz 1. His one-day mission had been plagued by a series of mishaps with the new type of spacecraft, which culminated in the capsule's parachute not opening properly after re-entry. Komarov was killed when the capsule hit the ground.
Four years later, on June 30, 1971, the crew of Soyuz 11, Georgi Dobrovolski, Viktor Patsayev and Vladislav Volkov were killed after un-docking from space station Salyut 1 after a three-week stay. A valve on their spacecraft had accidentally opened, allowing their air to leak out into space. The capsule re-entered and landed normally, and their deaths were only discovered when it was opened by the recovery team.
The first US in-flight disaster came on January 28, 1986 when the space shuttle Challenger was destroyed 75 seconds after launch. Analysis of the accident showed that a faulty seal ("O-Ring") had allowed hot gasses from one of the shuttle's booster rockets to weaken the mounting that held the booster to the shuttle's large external fuel tank. When the mounting failed, the top of the booster rocket struck the fuel tank and ruptured it. Challenger was torn apart in mid-air with the loss of all seven crew members aboard- Greg Jarvis, Christa McAuliffe, Ronald McNair, Ellison Onizuka, Judith Resnik, Michael J. Smith, and Dick Scobee.
A second shuttle, Columbia, was lost on February 1, 2003 as she re-entered after a two-week mission. Damage to the shuttle's thermal protection tiles led to structural failure in the shuttle's left wing and, ultimately, the spacecraft breaking apart. At the time of writing, investigations are focused on a piece of insulation foam that broke away from the external fuel tank during launch and hit the shuttle's wing. Rick Husband, William McCool, Michael Anderson, David Brown, Kalpana Chawla, Laurel Clark and Ilan Ramon were killed.
In addition to accidents on actual spaceflights, astronauts have been killed while in training.
On March 23, 1961, Valentin Bondarenko[?] became the first space-related casualty of all while undergoing training in a special low-pressure chamber with a pure oxygen atmosphere. Bondarkenko accidentally dropped an alcohol-soaked cloth onto an electric hotplate. In the pure oxygen environment, the fire quickly engulfed the entire chamber. Bondarenko was barely alive when the chamber was opened, and died of his burns in hospital a short time later.
On October 31, 1964, Theodore Freeman[?] was killed when a goose was pulled into the engine of his T-38[?] jet trainer. Freeman ejected from the stricken aircraft, but was too close to the ground for his parachute to open properly.
The Gemini 9[?] crew, Elliot See[?] and Charles Bassett[?] were killed whilst attempting to land their T-38 in bad weather on 28 February 1966. See misjudged his approach, and crashed into the McDonnell aircraft factory.
Another fire claimed the lives of the Apollo 1 crew as they trained in their capsule on January 27, 1967. An electrical fault sparked the blaze that again spread quickly in a pure oxygen atmosphere, killing Virgil Grissom, Edward White and Roger Chaffee. At the time of the accident, Bondarenko's death had been covered up by the Soviet government and was not known about in the US. If only it had been, perhaps the dangers of equipping spacecraft with pure oxygen atmospheres would have been more fully appreciated and the tragedy averted.
In yet another T-38 crash, Clifton Williams[?] was killed on October 5, 1967 after a mechanical failure caused his controls to stop responding. He had been assigned to the back-up crew for what would be the Apollo 9 mission and would have most likely been assigned as Lunar Module pilot for Apollo 12. The Apollo 12 mission patch has four stars on it - one each for the three astronauts who flew the mission, and one for Williams.
Apart from actual disasters, a number of missions resulted in some very near misses. These have included various re-entry mishaps (in particular on Soyuz 5), the sinking of the Mercury 4 capsule, and the Voskhod 2 crew spending a night in dense forest surrounded by wolves. Additionally:
In the most celebrated "near miss", the Apollo 13 crew came home safely after an explosion on April 14, 1970 crippled their spacecraft en route to the moon. They survived the loss of most of their spacecraft systems by relying on the Lunar Module to provide life-support and power for the trip home.
On April 5, 1975, the Soyuz 18a mission nearly ended in disaster when the rocket malfunctioned during launch. The Soyuz's escape system pulled the capsule clear, but subjected the crew to an extremely rough return to earth.