There have been a number of Spaceflight accidents and incidents in the history of spaceflight. In particular, incidents during human spaceflight missions have resulted in 18 astronaut fatalities, as of 2010.^{[1][nb 1]} Additionally, there have been some astronaut fatalities during other spaceflight-related activities, such as the Apollo 1 launch pad fire which killed all three crew members. There have also been some non-astronaut fatalities during spaceflight-related activities.

This article provides an overview of all known fatalities and near-fatalities that occurred during manned space missions, accidents during astronaut training and during the testing, assembling or preparing for flight of manned and unmanned spacecraft. Not included are fatalities occurring during intercontinental ballistic missile accidents, and Soviet or German rocket-fighter projects of World War II.^{[clarification needed]} Also not included are alleged unreported Soviet space accidents that are not believed by mainstream historians to have occurred.

Astronaut fatalities during spaceflight

(In the statistics below, "astronaut" is applied to all space travellers to avoid the use of "astronaut/cosmonaut".)

The history of space exploration has had a number of incidents that resulted in the deaths of the astronauts during a space mission. As of 2010^[update], in-flight accidents have killed 18 astronauts, in four separate incidents.^{[nb 2]}

NASA astronauts who have lost their lives in the line of duty are memorialized at the Space Mirror Memorial at the Kennedy Space Center Visitor Complex in Merritt Island, Florida. Cosmonauts who have died in the line of duty under the auspices of the Soviet Union were generally honored by burial at the Kremlin Wall Necropolis in Moscow. It is unknown whether this remains tradition for Russia, since the Kremlin Wall Necropolis was largely a Communist honor and no cosmonauts have died in action since the Soviet Union fell.

There have been four fatal in-flight accidents on missions which were considered spaceflights under the internationally accepted definition of the term, plus one on the ground during rehearsal of a planned flight. In each case all crew were killed. To date, there has never been an incident where an individual member of a multi-member crew has died during (or while rehearsing) a mission.

Incident	Date	Mission	Fatalities	Description
Parachute failure	1967 April 24	Soyuz 1	Vladimir Komarov	The 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 atmospheric reentry. Komarov was killed when the capsule hit the ground at high speed.
Crew exposed to vacuum of space	1971 June 30	Soyuz 11	Georgi Dobrovolski  Viktor Patsayev  Vladislav Volkov	The crew of Soyuz 11 were killed after undocking from space station Salyut 1 after a three-week stay. A valve on their spacecraft had accidentally opened when the service module separated, which was only discovered when the module was opened by the recovery team. Technically the only fatalities in space (above 100 km).
Space Shuttle Challenger disaster	1986 January 28	STS-51-L	Greg Jarvis  Christa McAuliffe  Ronald McNair  Ellison Onizuka  Judith Resnik  Michael J. Smith  Dick Scobee	The first U.S. multiple in-flight fatalities. The Space Shuttle Challenger was destroyed 73 seconds after lift-off on STS-51-L. Analysis of the accident showed that a faulty O-ring seal had allowed hot gases from the shuttle solid rocket booster (SRB) to weaken the external propellant tank, and also the strut that held the booster to the tank. The tank aft region failed, causing it to begin disintegrating. The SRB strut also failed, causing the SRB to rotate inward and expedite tank breakup. Challenger was thrown sideways into the Mach 1.8 windstream causing it to break up in midair with the loss of all seven crew members aboard. NASA investigators determined they may have survived during the spacecraft disintegration, while possibly unconscious from hypoxia; at least some of them tried to protect themselves by activating their emergency oxygen. Any survivors of the breakup were killed, however, when the largely intact cockpit hit the water at 200 mph (320 km/h).
Space Shuttle Columbia disaster	2003 February 1	STS-107	Rick D. Husband  William McCool  Michael P. Anderson  David M. Brown  Kalpana Chawla  Laurel B. Clark  Ilan Ramon	The Space Shuttle Columbia was lost as it reentered at the end of a two-week mission, STS-107. Damage to the shuttle's thermal protection system (TPS) led to structural failure in the shuttle's left wing and, ultimately, the spacecraft broke apart. Investigations after the tragedy revealed the damage to the reinforced carbon-carbon leading edge wing panel had resulted from a piece of insulation foam breaking away from the external tank during the launch and hitting shuttle's wing.

There has also been a single accident on a flight which was considered a spaceflight by those involved in conducting it, but not under the internationally accepted definition:

• 1967 November 15: control failure: Michael J. Adams died while piloting a North American X-15 rocket plane. Major Adams was a U.S. Air Force pilot in the NASA/USAF X-15 program. During X-15 Flight 191, his seventh flight, the plane first had an electrical problem and then developed control problems at the apogee of its flight. The pilot may also have become disoriented. During reentry from a 266,000 ft (50.4 mile, 81.1 km) apogee, the X-15 yawed sideways out of control and went into a spin at a speed of Mach 5. The pilot recovered, but went into a Mach 4.7 inverted dive. Excessive acceleration led to the X-15 breaking up in flight at about 65,000 feet (19.8 km)).^[3] Adams was posthumously awarded astronaut wings as his flight had passed an altitude of 50 miles (80.5 km) (the U.S. definition of space).^[4]

Average deaths per spaceflight

There are various ways of measuring the danger of spaceflight based on comparing the number of fatalities to the number of non-fatal spaceflights.

About two percent of the manned launch/reentry attempts have killed their crew, with Soyuz and the Shuttle having almost the same death percentage rates. Except for the X-15 (which is a suborbital rocket plane), other launchers have not launched sufficiently often for reasonable safety comparisons to be made.

About five percent of the people that have been launched have died doing so. As of November 2004^[update], 439 individuals have flown on spaceflights: Russia/Soviet Union (96), USA (277), others (66).^{[citation needed]} Twenty-two have died while in a spacecraft: three on Apollo 1, one on Soyuz 1, one on X-15-3, three on Soyuz 11, seven on Challenger, and seven on Columbia. By space program, 18 NASA astronauts (4.1%) and four Russian cosmonauts (0.9% of all the people launched) died while in a spacecraft.^{[needs update]}

Soyuz accidents have claimed the lives of four cosmonauts. No deaths have occurred on Soyuz missions since 1971, and none with the current design of the Soyuz. Including the early Soyuz design, the average deaths per launched crew member on Soyuz are currently under two percent. However, there have also been several serious injuries, and some other incidents in which crews nearly died.

Near-fatalities

Apart from actual disasters, a number of missions resulted in some very near misses and also some training accidents that nearly resulted in deaths. In-flight near misses have included various reentry 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.

• 1961 April 12: separation failure: During the flight of Vostok 1, after retrofire, the Vostok service module unexpectedly remained attached to the reentry module by a bundle of wires. The two halves of the craft were supposed to separate ten seconds after retrofire. But they did not separate until 10 minutes after retrofire, when the wire bundle finally burned through. The spacecraft had gone through wild gyrations at the beginning of reentry, before the wires burned through and the reentry module settled into the proper reentry attitude.
• 1961 July 21: landing capsule sank in water: After Liberty Bell 7 splashed down in the Atlantic, the hatch malfunctioned and blew, filling the capsule with water and almost drowning Gus Grissom, who managed to escape before it sank. Grissom then had to deal with a spacesuit that was rapidly filling with water, but managed to get into the helicopter's retrieval collar and was lifted to safety.^[5]
• 1965 March 18: spacesuit or airlock design fault: Voskhod 2 featured the world's first spacewalk, by Alexei Leonov. After his twelve minutes outside, Leonov's spacesuit had inflated in the vacuum to the point where he could not reenter the airlock. He opened a valve to allow some of the suit's pressure to bleed off, and was barely able to get back inside the capsule after suffering slight effects of the bends.
• 1966 March 17: equipment failure: Gemini 8: A maneuvering thruster refused to shut down and put their capsule into an uncontrolled spin. The g-force became so intense the astronauts were possibly within seconds of blacking out when they regained control.^[6]
• 1969 January 18: separation failure: the Soyuz 5 had a harrowing reentry and landing when the capsule's service module initially refused to separate, causing the spacecraft to begin reentry faced the wrong way. The service module broke away before the capsule would have been destroyed, and so it made a rough but survivable landing far off course in the Ural mountains.
• 1970 April 13: equipment failure: In the most celebrated "near miss", the Apollo 13 crew came home safely after a violent rupture of a liquid oxygen tank^[7] deprived the Service Module of its ability to produce electrical power, crippling their spacecraft en route to the moon. They survived the loss of use of their command ship by relying on the Lunar Module as a "life boat" to provide life support and power for the trip home.^[8]
• 1975 April 5: separation failure: The Soyuz 18a mission nearly ended in disaster when the rocket suffered a second-stage separation failure during launch. This also interrupted the craft's attitude, causing the vehicle to accelerate towards the Earth and triggering an emergency reentry sequence. Due to the downward acceleration, the crew experienced an acceleration of 21.3 g rather than the nominal 15 g for an abort. Upon landing, the vehicle rolled down a hill and stopped just short of a high cliff. The crew survived, but Lazarev, the mission commander, suffered internal injuries due to the severe G-forces and was never able to fly again.
• 1975 July 24: gas poisoning on board: During final descent and parachute deployment for the Apollo Soyuz Test Project Command Module, the U.S. crew were exposed to 300 µL/L of toxic nitrogen tetroxide gas (Reaction Control System oxidizer) venting from the spacecraft and reentering a cabin air intake. A switch was left in the wrong position. 400µL/L is fatal. Vance Brand's heart stopped and he was narrowly resuscitated.^{[citation needed]} The crew members suffered from burning sensations of their eyes, faces, noses, throats and lungs. Thomas Stafford quickly broke out emergency oxygen masks and put one on Brand and gave one to Deke Slayton. The crew were exposed to the toxic gas from 24,000 ft (7.3 km) down to landing. About an hour after landing the crew developed chemical-induced pneumonia and their lungs had edema. They experienced shortness of breath and were hospitalized in Hawaii. The crew spent two weeks in the hospital. By July 30, their chest X-rays appeared to return to normal.^[9]
• 1976 October 16: landing capsule sank in water: The Soyuz 23 capsule broke through the surface of a frozen lake and was dragged underwater by its parachute. The crew was saved after a very difficult rescue operation.
• 1983 September 26: fire in launch vehicle: A Soyuz crew was saved by their escape system when the rocket that was to carry their Soyuz T-10-1 mission into space caught fire on the launchpad.
• 1985 July 29: STS-51-F: Space Shuttle in-flight engine failure: Five minutes, 45 seconds into ascent, one of three shuttle main engines aboard Challenger shut down prematurely due to a spurious high temperature reading. At about the same time, a second main engine almost shut down from a similar problem, but this was observed and inhibited by a fast acting flight controller. The failed SSME resulted in an Abort To Orbit (ATO) trajectory, whereby the shuttle achieves a lower than planned orbital altitude. Had the second engine failed within about 20 seconds of the first, a Transatlantic Landing (TAL) abort might have been necessary. (No bailout option existed until after mission STS-51-L (Challenger disaster), but even today a bailout—a "contingency abort", would never be considered when an "intact abort" option exists, and after five minutes of normal flight it would always exist unless a serious flight control failure or some other major problem beyond engine shutdown occurred.^[10])
• 1988 September 5: sensor failure: Soyuz TM-5 cosmonauts Alexandr Lyakhov and Abdul Ahad Mohmand (from Afghanistan) undocked from Mir. They jettisoned the orbital module and got ready for the deorbit burn. The deorbit burn did not occur because the infrared horizon sensor could not confirm proper attitude. Seven minutes later, the correct attitude was achieved. The main engine fired, but Lyakhov shut it down after 3 seconds to prevent a landing overshoot. A second firing 3 hours later lasted only 6 seconds. Lyakhov immediately attempted to manually deorbit the craft, but the computer shut down the engine after 60 seconds. When they were jettisoning the Equipment Module, which contained, among other things, the primary propulsion system – the very system they needed to deorbit – Mohmand, disregarding a directive to sit back and let Mission Control assess the situation, had scanned the ship’s gauges and displays, and discovered that separation was going to take place in less than a minute. Lyakhov quickly disabled the program. Had he not done so, he and Mohmand would have perished, as the Soyuz Descent Module had only enough air and battery power for a couple of hours. After three attempts at retrofire, the cosmonauts were forced to remain in orbit a further day, until they came into alignment with the targeted landing site again. Even if they had enough fuel to do so, they would not have been able to re-dock with Mir, because they had discarded the docking system along with the orbital module. The cosmonauts were left for a day in the cramped quarters of the descent module with minimal food and water and no sanitary facilities. Reentry occurred as normal on September 7, 1988.
• 1997 February 23: fire onboard: There was a fire on board the Mir space station when a lithium perchlorate canister used to generate oxygen leaked. The fire was extinguished after about 90 seconds, but smoke did not clear for several minutes.
• 1997 June 25: collision in space: At Mir during a re-docking test with the Progress-M 34 cargo freighter, the Progress freighter collided with the Spektr module and solar arrays of the Mir space station. This damaged the solar arrays and the collision punctured a hole in the Spektr module and the space station began depressurizing. The on-board crew of two Russians and one visiting NASA astronaut were able to close off the Spektr module from the rest of Mir after quickly cutting cables and hoses blocking hatch closure.
• 1999 July 23: STS-93: main engine electrical short and hydrogen leak: Five seconds after liftoff, an electrical short knocked out controllers for two shuttle main engines. The engines automatically switched to their backup controllers. Had a further short shut down two engines, Columbia would have ditched in the ocean, although the crew could have possibly bailed out. Concurrently a pin came loose inside one engine and ruptured a cooling line, allowing a hydrogen fuel leak. This caused premature fuel exhaustion, but the vehicle safely achieved a slightly lower orbit. Had the failure propagated further, a risky transatlantic or RTLS abort would have been required.
• 2008 April 19: Soyuz TMA-11 suffered a reentry mishap similar to that suffered by Soyuz 5 in 1969. The service module failed to completely separate from the reentry vehicle and caused it to face the wrong way during the early portion of aerobraking. As with Soyuz 5, the service module eventually separated and the reentry vehicle completed a rough but survivable landing. Following the Russian news agency Interfax's report, this was widely reported as life-threatening^[11][12] while NASA urged caution pending an investigation of the vehicle.^[13]
• On one Shuttle flight^[which?], wiring faults threatened to prevent the main tank from separating.

Training accidents

In addition to accidents during spaceflights, astronauts have experienced accidents during training. Training accidents have resulted in 10 astronaut deaths.^{[nb 1]}

• 1961 March 23: fire on board: First space-related casualty. Valentin Bondarenko was in training in a special low-pressure chamber with a pure oxygen atmosphere. He threw an alcohol-soaked cloth onto an electric hotplate. In the pure oxygen environment, the fire quickly engulfed the entire chamber. Bondarenko suffered third-degree burns over most of his body and was barely alive when the chamber was opened, and died of his burns shortly after being hospitalized. Bondarenko's death was covered up by the Soviet government; word of his death only reached the West in 1986. Many materials become explosively flammable when exposed to oxygen with a higher partial pressure than that of air at STP; modern spacecraft use mixtures of continuously replaced oxygen and nitrogen. It has been speculated that knowledge of Bondarenko's death might have led to changes that would have prevented the Apollo 1 fire.
• 1964 October 31: bird strike: Theodore Freeman was killed when a goose smashed through the cockpit canopy of his T-38 jet trainer. Flying shards of Plexiglas entered the engine intake and caused the engine to flame out. Freeman ejected from the stricken aircraft, but was too close to the ground for his parachute to open properly.^[14] The creation of zero-zero ejection seats has eliminated this problem. (However, T-38s remaining in service still do not have a zero-zero ejection seat.)
• 1966 February 28: crash on landing: The original Gemini 9 crew, Elliot See and Charles Bassett, were killed while attempting to land their T-38 in bad weather. See misjudged his approach and crashed into the McDonnell aircraft factory.^[15]
• 1967 January 27: fire on board: A fire in the cabin claimed the lives of the Apollo 1 crew as they rehearsed the launch sequence for their planned February 21 launch. An electrical fault sparked the blaze that spread quickly in a pure oxygen atmosphere, killing Gus Grissom, Edward White II, and Roger Chaffee.
• 1967 October 5: controls failed: Clifton "C.C." Williams died after a mechanical failure caused the controls of his T-38 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.^[16]
• 1967 December 8: plane crash: Robert Henry Lawrence, Jr. was named the first African-American astronaut for the U.S. Air Force Manned Orbiting Laboratory program, but he never made it into space. He died when his F-104 Starfighter jet crashed at Edwards Air Force Base, California.^[17]
• 1968 March 27: plane crash: First human in space Yuri Gagarin died when his MiG-15UTI jet trainer crashed while he prepared for the Soyuz 3 mission.^[18] An official report at the time blamed either birdstrike or that he turned too fast to avoid something in the air. But in 2003 it came to light that the KGB had found that the official report was false and that the truth was negligence by an air force colonel on the ground, who gave an out-of-date weather report; the flight needed good weather and the aircraft not to have external extra fuel tanks, but the cloud base was nearly at ground level and the aircraft had external fuel tanks under its wings. Since Gagarin was a very public figure, the Soviet government decided that it would be bad publicity to have him killed in a mere training accident and so several newspapers printed the report that he actually died heroically testing a top-secret prototype. This again led to speculation amongst Western conspiracy-proponents as to whether Gagarin had instead died in hushed-up spacecraft accident (see Lost cosmonauts, conspiracy theory).
• Three of the five Lunar Landing Research and Training vehicles (LLRV and LLTV) were destroyed in crashes near Houston, Texas:
  • 1968 May 6: LLRV No. 1 crashed at Ellington AFB, Texas, caused by loss of helium pressure that controlled the steering jets. Neil Armstrong ejected safely.^[19]
  • 1968 December 8: LLTV No. 1 crashed at Ellington AFB, Texas, caused by failure of the fly-by-wire control system. MSC test pilot Joseph Algranti ejected safely.^[20]
  • 1971 January 29: An LLTV crashed at Ellington AFB, Texas, caused by failure of the fly-by-wire control system. NASA test pilot Stuart Present ejected safely.^[21]
• 1971 January 23: helicopter crash: Eugene Cernan was flying a Bell 47G helicopter as part of his Lunar Module training as Backup Commander for Apollo 14. The helicopter crashed into the Banana River at Cape Canaveral, Florida. Cernan nearly drowned because he was not wearing a life vest and received some second-degree burns on his face and singed hair.^[22] According to official reports at the time, the crash was the result of mechanical failure. Later accounts, written by Cernan himself in an autobiography, admit he was flying too low and showing off for nearby boaters. The helicopter dipped a skid into the water and crashed. James McDivitt, an Apollo Manager at the time, demanded that Cernan be removed from flight status and not be given Command of Apollo 17. Cernan was defended by Deke Slayton and given the Apollo 17 command. James McDivitt resigned as an Apollo Manager shortly after the Apollo 16 mission.^[23]

Fatal accidents with ground crew and civilian fatalities

Launchpad accidents have killed at least 71 ground personnel. ((citation)): Empty citation (help)^{[needs update]}