Soyuz 11

Backup crew Original crew Crew notes The original prime crew for Soyuz 11 consisted of Alexei Leonov, Valery Kubasov, and Pyotr Kolodin. A medical X-ray examination four days before launch suggested that Kubasov might have tuberculosis, and according to the mission rules, the prime crew was replaced with the backup crew. For Dobrovolsky and Patsayev, this was to be their first space mission. After the failure of Salyut 2 to orbit, Kubasov and Leonov were reassigned to Soyuz 19 for the Apollo-Soyuz Test Project in 1975. == Mission ==

Parameters • Mass: • Perigee: • Apogee: • Inclination: 51.6° • Period: 88.3 minutes Flight The Soyuz 7K-OKS spacecraft was launched on 6 June 1971, from the Baikonur Cosmodrome in the central Kazakh Soviet Socialist Republic, and used the callsign Yantar (Amber). Several months earlier, the first mission to the Salyut, Soyuz 10, had failed to dock successfully with the station. During the first day of the flight, maneuvers were made to effect a rendezvous with the uncrewed Salyut (1971-032A). When Soyuz 11 was from Salyut, automatic devices took over, and in 24 minutes closed the gap between the two ships to and reduced the relative speed difference to . Control of the ships went from automatic back to manual at . Docking took 3 hours 19 minutes to complete and involved making the connection mechanically rigid, engaging various electrical and hydraulic links, and establishing air-tight seals before locks could be opened. When the pressure was equalized between the ships, the locks were opened and all three members of the crew passed into Salyut 1. Soyuz 11 successfully docked with Salyut 1 on 7 June 1971 and the cosmonauts remained on board for 22 days, setting space endurance records that would hold until the American Skylab 2 mission in May and June 1973. The crew also found that using the exercise treadmill, as they were required to twice a day, caused the whole station to vibrate. Kerim Kerimov, chair of the State Commission, recalled: "Outwardly, there was no damage whatsoever. They knocked on the side, but there was no response from within. On opening the hatch, they found all three men in their couches, motionless, with dark-blue patches on their faces and trails of blood from their noses and ears. They removed them from the descent module. Dobrovolsky was still warm. The doctors gave artificial respiration. Based on their reports, the cause of death was suffocation". Cause of death It quickly became apparent that the cosmonauts had asphyxiated. The fault was traced to a breathing ventilation valve, located between the orbital module and the descent module, that had been jolted open as the descent module separated from the service module, 12 minutes and 3 seconds after retrofire. The two modules were held together by explosive bolts designed to fire sequentially; in fact, they had fired simultaneously. The valve was located beneath the seats and was impossible to find and block before the air was lost. Flight recorder data from the single cosmonaut outfitted with biomedical sensors showed cardiac arrest occurred within 40 seconds of pressure loss. By 15 minutes 35 seconds after retrofire, the cabin pressure was zero, and remained there until the capsule entered the Earth's atmosphere. Patsayev's body was found positioned near the valve, and he may have been attempting to close or block the valve at the time he lost consciousness. An extensive investigation was conducted to study all components and systems of Soyuz 11 that could have caused the accident, although doctors quickly concluded that the cosmonauts had died of asphyxiation. The autopsies at Burdenko Main Military Clinical Hospital found that the cause of death for the cosmonauts was haemorrhaging of the blood vessels in their brains, with lesser amounts of bleeding under their skin, in their inner ears, and in their nasal cavities, all of which occurred as exposure to a vacuum environment caused the oxygen and nitrogen in their bloodstreams to bubble and rupture vessels. Their blood was also found to contain heavy concentrations of lactic acid; lactic acid buildup (in tissues and blood) is a sign of inadequate mitochondrial oxygenation, which may be due to hypoxemia (low blood oxygen), poor blood flow (e.g., decompression) or a combination of both. Although they could have remained conscious for almost 40 seconds after decompression began, less than 20 seconds would have passed before the effects of oxygen starvation made it impossible for them to function. == Aftermath ==

Alexei Leonov, who would have originally commanded Soyuz 11, had advised the cosmonauts before the flight that they should manually close the valves between the orbital and descent modules, as he did not trust them to shut automatically, a procedure he thought up during extensive time in the Soyuz simulator. However, it appears that the crew did not do this. After the flight, Leonov went back and tried closing one of the valves himself, and found that it took nearly a minute to do so, too long in an emergency situation with the spacecraft's atmosphere escaping fast. Until autopsy, they were not known to have died because of a capsule depressurisation. The ground crew had lost audio contact with the crew before re-entry began, and had already begun preparations for contingencies in case the crew had been lost. The cosmonauts were given a large state funeral and buried in the Kremlin Wall Necropolis at Red Square, Moscow, near the remains of Yuri Gagarin. They were also each posthumously awarded the Hero of the Soviet Union medal. The United States sent Tom Stafford, then NASA's Chief Astronaut, to represent President Richard Nixon at the funeral, where the Soviets asked him to be one of the pallbearers. It came at the beginning of a period of more cordial relations between the two nations that would lead to the joint Apollo–Soyuz mission. President Nixon also issued an official statement following the accident: The Soyuz spacecraft was extensively redesigned after this incident to carry only two cosmonauts. The extra room meant that the crew could wear Sokol space suits during launch and landing. The Sokol was a lightweight pressure suit intended for emergency use; updated versions of the suit remain in use. == Memorials ==

The Soyuz 11 landed south-west of Karazhal, Karagandy, Kazakhstan, and about north-east of Baikonur. A memorial monument in the form of a three-sided metallic column, with the engraved image of the face of each crew member set into a stylized triangle on each of the three sides, was placed at the site. The memorial is in open, flat country, far from any populated area, within a small, circular fence. In 2012, the memorial was found to have been vandalized beyond repair, with only the base of the metallic column remaining and any roads leading to it overgrown. In 2013, Russian space agency Roscosmos restored the site with a redesigned monument, reflecting the three-sided form of the original, but this time constructed from brick. Also placed at the site was a sign explaining the history of the location and the fate of the original monument. Craters on the Moon were named after the three cosmonauts: Dobrovolʹskiy, Volkov, and Patsaev. The names of the three cosmonauts are included on the Fallen Astronaut commemorative plaque placed on the Moon during the Apollo 15 mission in August 1971. To honour the loss of the Soyuz 11 crew, a group of hills on Pluto is also named Soyuz Colles. In the city of Penza, Russia, near the school gymnasium No. 39, in honour of the dead cosmonauts, a memorial stele was made with quotes from the poem by the poet Yevgeny Yevtushenko "Between our Motherland and you is a two-way eternal connection" (). In addition to the Soviet postage stamp depicted above, a series of postage stamps of the Emirate of Ajman and Bulgaria was issued in memory of the cosmonauts in 1971. Equatorial Guinea also released a series of stamps depicting the entire Soyuz 11 mission. == See also ==