On the morning of June 30, 1971, near sunrise on the steppes of Kazakhstan, recovery crews prepared to receive the crew of Soyuz 11, which had completed a successful 24-day mission to the world’s first space station: Salyut 1. The Soviet leadership and public were eager to welcome cosmonauts Georgi Dobrovolski, Vladislav Volkov, and Viktor Patsayev home after they broke the world spaceflight endurance record of 18 days, set a year earlier by their countrymen aboard Soyuz 9.

The Soyuz 11 descent module’s parachute system started to deploy as planned, at approximately 10 kilometers in altitude, and the main parachute deployed nominally. There had not been communications with the crew since before the deorbit burn, but ground crews were preparing for what they expected would be a nominal return from orbit.

The descent module completed a nominal touchdown at the landing site east of Dzhezkazgan, an area still used today for Soyuz landings. The spacecraft landed on its side on a beautiful day with a clear sky with recovery forces in a good position to receive the crew. The recovery teams proceeded to safe the spacecraft and opened the hatch.

What they found inside Soyuz 11 would shock and devastate them, with severe consequences to the Soviet program, and would spawn safety modifications and equipment that are in use in the present day.

Soyuz 11’s three person crew were dead.

Soyuz 11

The Salyut project, to launch the world’s first orbiting space station for crews to visit, live in, and conduct research on had been approved by the Soviet program in the wake of the Apollo 11 lunar landing. Since the Soviets had lost the race to land humans on the Moon and were having serious problems with their N-1 heavy lift rocket needed for their own lunar landing missions, they decided to focus on other space firsts that they could get ahead of the Americans.

The Soyuz 11 crew: (left to right) Dobrovolsky, Volkov and Patsayev. (Credit: Roscosmos/USSR historical archive)

Soviet program leadership decided upon long duration orbital missions as the way ahead for their spaceflight efforts while the N-1 issues were still in work. These missions started in June 1970 with Soyuz 9, when cosmonauts Andrian Nikolayev and Vitaly Sevastyanov flew aboard the last first generation Soyuz 7K-OK spacecraft for 18 days, conducting biomedical experiments, earth observations, and stellar navigation exercises — validating the possibility of longer flights aboard the Salyut station to come.

On the morning of April 19, 1971 a Proton-K rocket launched from Baikonur Site 81/24 with the Salyut 1 space station on top, a station that was based on a design called Almaz — originally started by designer Vladimir Chelomei as a military response to the US Air Force’s Manned Orbiting Laboratory project. The Salyut station, a fully equipped dry workshop, successfully reached a 200 x 222 km orbit above Earth and was checked out in preparation to receive cosmonaut crews, beating the NASA Skylab program to orbit by two years.

The Soyuz 10 mission, commanded by Vladimir Shatalov, with flight engineer Alexei Yeliseyev and systems engineer Nikolai Rukavishnikov, would be the first flight of the new Soyuz 7K-OKS — with a probe and drogue docking system as well as an internal transfer tunnel. The mission marked the first time people were sent to an operational space station, 10 years after Yuri Gagarin’s pioneering flight.

The spacecraft launched on April 22nd and completed a rendezvous and soft docking with Salyut 1 to start what was planned to be the first stay by a crew at the new space station. However, an issue with the flight computer and attitude control system on Soyuz 10 caused the hard dock process to fail. After the crew had difficulty retracting the docking probe, they finally solved the issue, aborted the mission, left the station, and deorbited for a return to Earth on April 24th.

After working to understand and resolve the Soyuz 10 hard dock issues, the stage was set for another attempt to send crews to Salyut 1. The Soyuz 11 crew, commanded by famed cosmonaut Alexei Leonov, with flight engineer Valeri Kubasov and research engineer Pyotr Kolodin, was completing its training and preparing for a June 4 launch.

The crew, along with their backups of Georgi Dobrovolski, Vladislav Volkov, and Viktor Patsayev, made their way to Baikonur Cosmodrome as launch day approached.

On June 3rd, a decision was made due to a problem found during a routine preflight medical examination of the cosmonauts. Like the Apollo 13 crew the year before, a crew member was diagnosed with a last-minute condition that caused him to be replaced by his backup. However, the Soviet program’s process was different than NASA’s. The entire prime crew was replaced with the backup crew.

Doctors in Moscow found a dark spot on Kubasov’s right lung and diagnosed him with early stage tuberculosis. Kubasov’s diagnosis was not correct, and he did not become ill. According to Alexei Leonov’s memoir, Kubasov was allergic to an insecticide used on trees and quickly recovered. However, this did not matter to the Soviet space program leadership, and the backup crew was bumped up to the prime crew, being prepared for what would now become a June 6 launch for Soyuz 11.

New Soyuz 11 crew commander Georgi Dobrovolski, born in Odessa, Ukraine, was a lieutenant colonel in the Soviet Air Force, married with two children, and had been selected as a cosmonaut in 1963 along with other Soviet Air Force pilots in what was known as Group 2. After eight years in the cosmonaut corps, Dobrovolski was about to get his first flight in space.

The Soyuz 11 flight engineer, Vladislav Volkov, a native Muscovite, married with one child, was an engineer who worked on the Vostok and Voskhod projects for the Korolev design bureau before being named as a cosmonaut in 1966 as part of the Energia Engineer Cosmonaut Training Group 1. Unlike Dobrovolski, Volkov had prior experience in space, as a member of the Soyuz 7 crew that flew in October 1969.

Like Volkov, research engineer Viktor Patsayev was a civilian who worked for the Korolev design bureau. Born in Aktyubinsk, Kazakhstan, and married with two children, Patsayev was an engineer selected in the 1968 Civilian Specialist Group 3. Soyuz 11 would mark Patsayev’s first trip in space.

(Tweet translation: In memory of the Soyuz-11 crew. Today the world remembers three heroes – cosmonauts Georgy Timofeevich Dobrovolsky, Vladislav Nikolaevich Volkov and Viktor Ivanovich Patsaev. June 30 marks the 50th anniversary of their death: the Soyuz-11 crew:roscosmos.ru/31370/“)

On the morning of June 6, 1971, Soyuz 11 lifted off from Baikonur Site 1/5 “Gagarin’s Start” and successfully reached orbit. After 24 hours, Soyuz 11 and its crew, bestowed with the call sign “Yantar” (amber), successfully docked with Salyut 1 and overcame the issues with hard docking that plagued Soyuz 10, though not without some suspense due to the docking taking place out of communication with the ground.

The crew entered Salyut 1 but found an unpleasant odor in the air and had to replace two fans. With the air needing to pass through scrubbers, the crew spent the first night in their Soyuz then powered down the spacecraft afterwards to begin their planned 30 day stay on the Salyut station.

Salyut 1 had 99 cubic meters of pressurized volume, far more than the Soyuz 11’s nine cubic meters, and was by far the most commodious crewed spacecraft that had flown up to that time. The station featured a docking module with a tunnel and a fitting for the Orion UV stellar telescope, a wider forward work compartment with seats, control panels, and video and still cameras, and a wider and longer rear work compartment with biological experiments, a conical fitting for more experiments, a treadmill, sleep stations, and a food refrigeration unit.

Salyut 1 also contained an unpressurized compartment in the aft portion of the vehicle with systems taken directly from the Soyuz design, including thrusters and a deorbit engine as well as solar panels very similar if not identical to the panels on the Soyuz 7K-OKS spacecraft. Two additional solar panels were attached to the docking module, and rendezvous antennas were also fitted onto that docking module, using a system that has been developed over the years and is still in use today.

The Soyuz 11 crew started working on biological experiments and settled into a routine of living and working in space. The crew were featured on Soviet television and were followed and adored throughout the Soviet Union. They grew beards as the days went on and exercised on the treadmill to stay fit for reentry, but found that the treadmill vibrated the whole station. 

Viktor Patsayev celebrated his 38th birthday while in space, becoming the first person to do so.

Patsayev also became the first human being to operate an astronomical telescope in space when he used the Orion telescope to take ultraviolet stellar spectra, getting data from the stars Vega and Beta Centauri that was unobtainable from Earth’s surface.

Georgy Dobrovolsky. (Credit: USSR/Roscosmos)

The crew also photographed Earth from space, conducted military experiments, obtained medical data on themselves, and even grew flax plants in a small greenhouse called Oasis — the first of many experiments to grow crops in space. There were solar observations planned but a malfunctioning lens cover would not allow the solar telescope to be used.

However, the mission dynamics would change on June 16th. Vladislav Volkov noted a burning odor coming from the back of the station and also noted thick black smoke. He communicated this to Mission Control using a code word due to the Soviet program’s requirement for secrecy. However, the ground controllers had forgotten the code word, so Volkov had to use plain language to convey the severity of the situation.

The small fire was put out, after the crew had evacuated to Soyuz 11 and after equipment was turned off and back on. However, the fire and other issues caused the program to reevaluate the length of the Soyuz 11 mission. The decision was made to end the flight six days early, and on June 26th the crew finished all experiments. The cosmonauts focused their efforts on placing the station in “storage mode” and packing for the return to Earth, including some of the high priority experiment samples as Soyuz didn’t have room for all of the samples to come back.

On June 29, at 21:25 Moscow time, after some issues sealing the hatch on the Soyuz spacecraft that were resolved with the help of cosmonaut Alexei Yeliseyev communicating with Dobrovolski and his crew from mission control, Soyuz 11 undocked from Salyut 1 and backed away from the pioneering first space station.

Dobrovolski and his crew, clad in cloth flight suits similar to those worn by pilots, backed the spacecraft away from Salyut 1 and took photographs to document the condition of the station, in a procedure similar to what crews have done since with later Salyut stations, Skylab, Mir, and ISS. After they left the vicinity of the station, they prepared for the deorbit burn and the trip back to Earth.

Vladislav Volkov. (Credit: USSR/Roscosmos)

Dobrovolski reported to mission control in Russian “All received, landing sequence proceeding excellent, all OK, crew is excellent” after receiving instructions from mission control. At 01:35 Moscow time on June 30, 1971, the Soyuz 11’s deorbit engine fired for 187 seconds; the burn was nominal, though no communications were received from the crew after this point.

While the spacecraft was at 116 kilometers altitude, at 01:47 Moscow time, the orbital and propulsion modules separated from the descent module. Aboard the descent module, however, the crew had just been placed in mortal danger. 

A pressure equalization valve behind the control panel, meant to activate at 4 km altitude just before landing, activated prematurely due to the shock of the orbital and service module separations as the explosive bolts connecting them to the descent module all fired simultaneously rather than in sequence. As the spacecraft depressurized rapidly, the three men had just 13 seconds of useful consciousness to try to remedy the situation.

Dobrovolski and Patsayev tried to troubleshoot the situation. Patsayev was the cosmonaut closest to the valve that had opened, and investigations later suggested he may have tried to close the valve, but to no avail. 

Post-accident tests revealed it would have taken 52 seconds to close the valve manually, far longer than the crew actually had. Just 110 seconds after module separation, all three men lost their lives.

However, in mission control, while there was some concern due to the lack of communication, radar in Crimea in Ukraine picked up Soyuz 11 on a normal reentry path causing mission control to think all was well.

Viktor Patsayev. (Credit: USSR/Roscosmos)

Recovery forces on the Kazakh steppe were the first to realize what had happened upon opening Soyuz 11’s hatch. Medics tried CPR and resuscitation on the men for some minutes, but they had already passed over 30 minutes prior.

The Soviet public and the world first got word of the disaster via a TASS bulletin that began with the words “TASS reports the deaths of the crew of Soyuz 11”. An investigation into the disaster and the cause of the crew’s death was quickly established.

NASA astronaut Tom Stafford went to Moscow to represent the United States at the cosmonauts’ state funeral and while the Soyuz 11 crew lay in state and were posthumously awarded the Hero of the Soviet Union gold stars.

After Premier Leonid Brezhnev, other officials, and many ordinary citizens paid their respects, with Stafford serving as one of the pall bearers for the urns of the cremated remains, which were interred in the Kremlin Wall.

With an investigation complete, redesigning the pressure equalization valves and other aspects of the Soyuz spacecraft began, while the disaster’s effects even reached the Apollo program. 

In a seemingly unprecedented moment of rivals learning from each other during the Cold War, a decision was made to have the Apollo 15 lunar landing crew, Dave Scott and Jim Irwin, wear their A7L spacesuits during the ascent from the lunar surface.

The Soyuz 11 crew. (Credit: USSR/Roscosmos)

An uncrewed Soyuz mission in 1972 validated changes to the spacecraft, and the crew size was limited to two to accommodate a new launch and entry suit called Sokol-K. The suit, known as “Space Falcon” in Russian, was made for cosmonauts to wear during the launch and entry phases of every subsequent Soyuz flight starting with Soyuz 12 in September 1973.

While Dobrovolski, Volkov, and Patsayev gave the ultimate sacrifice 50 years ago today, and are the only humans to have died off Earth, their tragic loss came at the completion of their mission.  And while it’s easy to remember the physical reminders of their deaths in suits and redesigns and memorials, their work on Salyut 1 paved the way for so many elements of living in space that we largely take for granted today… that without them we would have had to have learned later.

Ultimately, every person who has left the planet since that fateful June morning in 1971 owes the Soyuz 11 crew a debt of gratitude… as do the billions of us who have benefited from their 24 day scientific research mission.

(Lead image: USSR postage stamp for Soyuz 11. Credit: USSR government. Retrieved from WikiCommons)

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