Soyuz 11
In the pioneering days of space exploration, the Soviet Union achieved a monumental first with Salyut 1, the world's inaugural space station. Soyuz 11 was the only mission to successfully dock with and inhabit this orbital outpost, a testament to human ingenuity and ambition. However, this historic triumph was tragically overshadowed by an unforeseen catastrophe, sealing the fate of its three-person crew and forever changing spacecraft design. Soyuz 11 marked a historic milestone by successfully delivering the first crew to the world's first space station, Salyut 1. A last-minute health concern led to a complete crew swap, sending the backup team—two of whom were on their first flight—into orbit. A tiny, critical valve failed during re-entry preparations, causing rapid cabin depressurization and the tragic death of all three cosmonauts, making them the only humans to have died in space.
AI Summary
In the pioneering days of space exploration, the Soviet Union achieved a monumental first with Salyut 1, the world's inaugural space station. Soyuz 11 was the only mission to successfully dock with and inhabit this orbital outpost, a testament to human ingenuity and ambition. However, this historic triumph was tragically overshadowed by an unforeseen catastrophe, sealing the fate of its three-person crew and forever changing spacecraft design.
- Soyuz 11 marked a historic milestone by successfully delivering the first crew to the world's first space station, Salyut 1.
- A last-minute health concern led to a complete crew swap, sending the backup team—two of whom were on their first flight—into orbit.
- A tiny, critical valve failed during re-entry preparations, causing rapid cabin depressurization and the tragic death of all three cosmonauts, making them the only humans to have died in space.
A Historic Journey Begins
In June 1971, the world watched as the Soviet Union launched Soyuz 11, a mission poised to make history. Its destination? Salyut 1, the planet's very first space station, already orbiting silently above. This was the USSR's bold next step in the space race, pushing the boundaries of human presence beyond Earth.
The Crew: A Twist of Fate
The crew consisted of Georgy Dobrovolsky, the commander; Vladislav Volkov, the flight engineer; and Viktor Patsayev, the research engineer. For Dobrovolsky and Patsayev, this was their inaugural journey into space, a dream realized through an unexpected turn of events.
Just four days before launch, the original prime crew—legendary cosmonaut Alexei Leonov, Valery Kubasov, and Pyotr Kolodin—was suddenly replaced. A medical X-ray suggested Kubasov might have tuberculosis, and strict mission rules demanded the entire crew be swapped out with the backup team. Fate, it seemed, had a different path in store for these men.
Position Cosmonaut Commander Georgy Dobrovolsky (Only spaceflight) Flight Engineer Vladislav Volkov (Second and last spaceflight) Research Engineer Viktor Patsayev (Only spaceflight)
Docking with Salyut 1
After a launch from the Baikonur Cosmodrome, the Soyuz 11 spacecraft, callsign 'Yantar' (Amber), began its delicate dance towards Salyut 1. A previous mission, Soyuz 10, had failed to dock, adding to the pressure. But on June 7, 1971, after three painstaking hours of maneuvering and sealing, Soyuz 11 successfully locked onto the station.
With a hiss of equalizing pressure, the hatches opened, and the three cosmonauts floated into humanity's first orbital home. They had officially become the first people to inhabit a space station, setting new endurance records that would stand for two years.
Life Aboard the Station
Their initial welcome to Salyut 1 was less than pristine—a smoky, burnt atmosphere greeted them. After replacing part of the ventilation system, they spent a day back in their Soyuz capsule until the air cleared. Despite this hiccup, their 22-day stay was incredibly productive, filled with scientific experiments and even live television broadcasts from orbit.
Life in space presented unique challenges. On day 11, a small fire broke out, causing mission control to consider an early abandonment. They also discovered that using the required exercise treadmill twice a day made the entire massive station vibrate, a strange and unsettling phenomenon high above Earth.
The Journey Home
After nearly three weeks, the time came to return. On June 29, 1971, the cosmonauts meticulously loaded scientific samples, films, and data into their Soyuz 11 ferry craft. They undocked from Salyut 1 and prepared for the perilous journey through Earth's atmosphere.
As the Soyuz module began its retro-fire, designed to slow it down for re-entry, the work compartment and service module were jettisoned. This separation was a critical, high-stress event. But something went catastrophically wrong: radio communications with the crew abruptly ceased, well before the expected atmospheric blackout.
Almost 25 minutes later, at 23:16:52 GMT, Soyuz 11's automatic systems guided the capsule to a silent, uneventful landing in Kazakhstan. Recovery teams rushed to the site, finding the capsule intact. But as the hatch was opened, a chilling discovery awaited them.
The Tragic Discovery
Inside, the three cosmonauts were found motionless in their couches. Kerim Kerimov, chairman of the State Commission, recounted finding them with dark-blue patches on their faces and trails of blood from their noses and ears. Dobrovolsky was still warm, but despite immediate resuscitation efforts, all three were declared dead. The cause was immediate and apparent: suffocation.
The Fatal Flaw
An urgent investigation quickly pinpointed the cause: a tiny breathing ventilation valve, located between the orbital and descent modules. This valve was designed to equalize pressure after landing, but it had opened prematurely, just 12 minutes and 3 seconds after retrofire, at an altitude of 168 kilometers (104 miles).
The valve was jolted open by the explosive bolts separating the modules. Instead of firing sequentially as intended, they fired simultaneously, creating a shockwave that dislodged the valve's internal seal. Air rushed out into the vacuum of space, a catastrophic depressurization that would prove fatal in less than a minute.
The cosmonauts, without pressure suits, were exposed to the vacuum. Biomedical sensors showed Dobrovolsky's heart stopped within 40 seconds. The cabin pressure plummeted to zero. Patsayev's body was found near the valve, suggesting a desperate, final attempt to close it, an impossible task in such a short, brutal timeframe.
Autopsies revealed the horrific effects of the vacuum: hemorrhaging in their brains, bleeding under their skin and in their ears, as oxygen and nitrogen in their blood literally boiled and bubbled, rupturing vessels. Within seconds, oxygen starvation would have rendered them unconscious, even if they could have held their breath.
Aftermath and Redesign
The Soviet state initially downplayed the tragedy, focusing on the mission's achievements. The true cause remained secret for nearly two years, causing concern among American space planners for their upcoming Skylab missions. However, Dr. Charles Berry of NASA correctly surmised the deaths were not due to microgravity, but a catastrophic failure.
The world mourned the loss of the three heroes. They were given a state funeral and buried with national honors in the Kremlin Wall Necropolis, alongside other Soviet luminaries like Yuri Gagarin. President Richard Nixon sent NASA's Chief Astronaut, Tom Stafford, to represent the U.S. at the funeral, a gesture that signaled a shift towards more cordial U.S.-Soviet relations.
The Soyuz spacecraft underwent a dramatic redesign after the incident. To ensure such a tragedy would never recur, the capsule was reconfigured to carry only two cosmonauts. This provided enough room for the crew to wear lightweight Sokol pressure suits during critical phases of flight, offering protection against depressurization. Modern versions of these suits are still in use today.
Remembering the Fallen
Today, monuments and memorials stand as somber reminders of Dobrovolsky, Volkov, and Patsayev. The landing site in Kazakhstan, once a remote expanse, now hosts a brick monument dedicated to their memory, replacing an earlier vandalized structure.
Beyond Earth, their names are etched into the cosmos. Craters on the Moon bear their names, and the Fallen Astronaut commemorative plaque placed on the Moon by Apollo 15 includes them. Even on distant Pluto, a group of hills is named Soyuz Colles, honoring the mission and its lost crew. They remain, forever, the only humans to have died in space.
Article
Soyuz 11
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.
Crew
Soyuz 11
<table><thead><tr><th>Position</th><th>Cosmonaut</th></tr></thead><tbody><tr><td>Commander</td><td>Georgy Dobrovolsky Only spaceflight</td></tr><tr><td>Flight engineer</td><td>Vladislav Volkov Second and last spaceflight</td></tr><tr><td>Research engineer</td><td>Viktor Patsayev Only spaceflight</td></tr></tbody></table>
Backup crew
<table><thead><tr><th>Position</th><th>Cosmonaut</th></tr></thead><tbody><tr><td>Commander</td><td>Aleksei Gubarev</td></tr><tr><td>Flight engineer</td><td>Vitaly Sevastyanov</td></tr><tr><td>Research engineer</td><td>Anatoly Voronov</td></tr></tbody></table>
Original crew
<table><thead><tr><th>Position</th><th>Cosmonaut</th></tr></thead><tbody><tr><td>Commander</td><td>Alexei Leonov</td></tr><tr><td>Flight engineer</td><td>Valery Kubasov</td></tr><tr><td>Research engineer</td><td>Pyotr Kolodin</td></tr></tbody></table>
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: 6,565 kg (14,473 lb) • Perigee: 185.0 km (115.0 mi; 99.9 nmi) • Apogee: 217.0 km (134.8 mi; 117.2 nmi) • 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 6 to 7 kilometres (3.7 to 4.3 mi; 3.2 to 3.8 nmi) from Salyut, automatic devices took over, and in 24 minutes closed the gap between the two ships to 9 metres (30 ft) and reduced the relative speed difference to 0.2 metres per second (0.66 ft/s). Control of the ships went from automatic back to manual at 100 metres (330 ft). 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.
Upon first entering the station, the crew encountered a smoky and burnt atmosphere, and after replacing part of the ventilation system, spent the next day back in their Soyuz until the air cleared. Their stay in Salyut was productive, including live television broadcasts. A fire broke out on day 11 of their stay, causing mission planners to consider abandoning the station. The planned highlight of the mission was to have been the observation of an N1 rocket launch, but the launch was postponed. The crew also found that using the exercise treadmill, as they were required to twice a day, caused the whole station to vibrate. Pravda released news of the mission and regular updates while it was in progress.
Re-entry and death
On 29 June 1971, the three cosmonauts loaded scientific specimens, films, tapes, and other gear into Soyuz 11, then transferred manual control back from Salyut 1 to Soyuz 11 and returned to their ferry craft, with undocking occurring at 18:28 GMT. Soyuz 11 flew co-orbit for a while before it retro-fired at 22:35 GMT in preparation for re-entry. Before re-entering Earth's atmosphere, both the work compartment and the service module were jettisoned. This occurred at about 22:47 GMT. Radio communications abruptly ended when the work compartment separated, well before the normal ionospheric blackout.
Almost 25 minutes later, Soyuz 11's automatic systems landed the craft at 23:16:52 GMT, 90 kilometres (56 mi; 49 nmi) southwest of Karazhal in Kazakhstan, after an abnormally silent return to Earth. The total flight duration of the crew had been 570.22 hours and involved 383 orbits—18 prior to docking, 362 docked, and three after undocking. When the recovery team opened the capsule of the Soyuz 11, they found all three men dead.
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 explosive force of the simultaneous bolt firing caused the internal mechanism of the pressure equalisation valve to loosen a seal that was usually discarded later and which normally allowed for automatic adjustment of the cabin pressure. The valve opened at an altitude of 168 kilometres (104 mi; 91 nmi), and the resultant loss of pressure was fatal in less than a minute. 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
Soyuz 11
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.
The Soviet state media attempted to downplay the tragic end of the mission, and instead emphasized its accomplishments during the crew's stay aboard Salyut 1. Since they did not publicly announce the exact cause of the cosmonauts' deaths for almost two years afterwards, United States space planners were extremely worried about the upcoming Skylab program, as they could not be certain whether prolonged time in a micro-g environment had turned out to be fatal. However, NASA doctor Charles Berry maintained a firm conviction that the cosmonauts could not have died from spending too many weeks in weightlessness. Until the Soviets finally disclosed what had really happened, Berry theorized that the crew had died from inhaling toxic substances.
A film that was later declassified showed support crews attempting cardiopulmonary resuscitation (CPR) on the cosmonauts. 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 American people join in expressing to you and the Soviet people our deepest sympathy on the tragic deaths of the three Soviet cosmonauts. The whole world followed the exploits of these courageous explorers of the unknown and shares the anguish of their tragedy. But the achievements of cosmonauts Dobrovolsky, Volkov and Patsayev remain. It will, I am sure, prove to have contributed greatly to the further achievements of the Soviet program for the exploration of space and thus to the widening of man's horizons.
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
Soyuz 11
The Soyuz 11 landed 90 kilometres (56 mi; 49 nmi) south-west of Karazhal, Karagandy, Kazakhstan, and about 550 kilometres (340 mi; 300 nmi) 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" (Russian: "Между Родиной нашей и вами – двусторонняя вечная связь").
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.