Soyuz 11

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Mission dates
Mission: Soyuz 11
NSSDCA ID : 1971-053A
Spacecraft: Soyuz 7K-T ( GRAY index  11F615A8)
serial number 32
Call sign: Янтарь (Jantar - " amber ")
Dimensions: 6790 kg
Launcher: Soyuz (GRAY index 11A511)
Crew: 3
Begin: June 6, 1971, 04:55:09  UT
Starting place: Baikonur 1/5
Space station: Salyut 1
Coupling: June 7, 1971, 07:49 UT
Decoupling: June 29, 1971, 6:28 pm UT
Duration on Salyut 1: 22d 10h 39m
Landing: June 29, 1971, 11:16:52 pm UT
Landing place: Kazakh SSR
47 ° 20 ′ N, 70 ° 24 ′ E
Flight duration: 23d 18h ​​21m 43s
Earth orbits: 384
Orbital time : 88.4 min
Apogee : 209 km
Perigee : 189 km
Team photo
Georgi Dobrowolski, Vladislav Volkov, Viktor Pazajew
Georgi Dobrowolski, Vladislav Volkov, Viktor Pazajew
◄ Before / After ►
Soyuz 10
(manned) 		Kosmos 496
(unmanned)
Next manned mission:
Soyuz 12

Soyuz 11 is the mission name for the flight of a Soviet Soyuz spacecraft to the Soviet space station Salyut 1, which started on June 6, 1971 . As a result of a technical malfunction during the landing phase, all three cosmonauts were killed. It was the first successful coupling of a spaceship to a space station and the 19th flight in the Soviet Soyuz program.

crew

The three cosmonauts were actually intended as a substitute team. The original crew for this long-term mission were Alexei Leonow , Pjotr ​​Kolodin and Valeri Kubasow . However, three days before the start, signs of tuberculosis were found in Kubasov, whereupon the entire team was replaced by the reserve team. However, the suspicion that Kubasov suffered from tuberculosis was not confirmed.

The second substitute team consisted of Alexei Gubarew , Vitaly Sevastyanov and Anatoly Voronow .

preparation

The Salyut space station

The first space station in history, Salyut 1, had been in orbit since April 19, 1971. Their equipment included a telescope, a spectrometer, an electrophotometer and a TV system. Swinet's secret radiometer was also on board, as was the Orion UV instrument, which could be used to observe rocket launches on Earth. The solar telescope was not ready for use because a cover on the outside of the space station had not been removed as intended.

The unsuccessful coupling of Soyuz 10

The first crew of the new space station should take place with Soyuz 10 . The spaceship approached the Salyut on April 24, 1971, but the coupling was not carried out at the correct angle, which is why the mechanism did not fully engage. The mission had to be aborted without the cosmonauts Shatalov , Jelissejew and Rukawischnikow having entered the space station.

Changes to the spaceship

Although the mechanism of Soyuz 10 was bent during the coupling attempt, the counterpart on Salyut 1 remained undamaged, so that it was sufficient to strengthen the coupling mechanism on Soyuz 11 to make another attempt. In addition, in contrast to Soyuz 10, Soyuz 11 should be able to stay autonomously in space for four days instead of three. In addition, the Igla approach and coupling system has been revised.

Further planning

The team originally intended for Soyuz 11 had previously acted as a substitute for Soyuz 10. The commanding officer was Alexei Leonov, who had carried out the first space exit in history at Vozhod 2 . He was a member of the first cosmonaut group in the Soviet Union. Another veteran on this team was Valery Kubasov, who was already in space with Soyuz 6 . Previously, he was a substitute for the flight, which was planned as Soyuz 2 but was canceled. Had Kubasov been deployed, he would have had to transfer from one spaceship to another. He then took on this role at Soyuz 5 . Pyotr Kolodin was a space rookie, but had previously been on the backup team at Soyuz 7 , Soyuz 8 and Soyuz 10.

A flight of 25 to 30 days was planned from June 1971, whereby a 30-day flight would have required a night landing.

It was also considered that the Soyuz 11 crew should carry out a space exit, on the one hand to examine the coupling socket of the Salyut, on the other hand to remove the cover of the scientific equipment on the outside of the space station. For this purpose only two cosmonauts could have started, the spaceship was too narrow for three people in space suits. This plan was rejected due to lack of time. By the time spacesuits were made and the cosmonauts trained, the Salyut would have reached the end of its useful life.

Soyuz 11's replacement crew was scheduled for another Soyuz 12 flight . The commander was the space novice Georgi Dobrowolski . Viktor Pazajew , who like Dobrowolski had not been on a substitute team before Soyuz 11, was also without space experience . Only Vladislav Volkov was previously in space with Soyuz 7. It was the first time an experienced cosmonaut was assigned to an inexperienced commander.

A 30-day flight was also planned for Soyuz 12; a take-off was planned between July 15 and 20. However, the space station was only designed for 90 days of operation, which expired on July 18, so that it was not clear whether and how long this flight would take place.

Exchange of teams

The two teams (Leonov, Kubassow and Kolodin as the main team, Dobrowolski, Wolkow and Pazayev as the substitute team) arrived in Baikonur on May 28th. On June 3, three days before the scheduled start, the intended team was again medically examined, and a shadow in Kubassov's lungs was discovered on an X-ray. The doctors diagnosed this as the onset of tuberculosis and denied him the ability to fly.

According to the regulations, the entire team had to be replaced. Instead of Leonov, Kubassow and Kolodin, Dobrowolski, Wolkow and Pazayev should now start for Salyut. The head of cosmonaut training, Nikolai Kamanin , was in favor of replacing only Kubasov with Volkov, but could not prevail. The following day - the diagnosis has since been confirmed by doctors who had traveled from Moscow - Dobrowolski's team was officially presented as the crew of Soyuz 11.

Flight history

Start, docking and switching to Salyut 1

Soyuz 11 took off on June 6, 1971 at 04:55 UTC and reached Earth orbit without any problems. The flight control changed from the starting point Baikonur to the ground station in Yevpatoria .

After two course corrections, Soyuz 11 came within seven kilometers of the space station, after which the Igla automatic approach and coupling system was activated. This time the crew did not have to intervene in the automatic sequence. The pairing itself took place on June 7th at 07:49 UTC out of range of the ground stations, and when the connection could be re-established, Dobrowolski reported the successful pairing. After four orbits together, all checks were completed and Viktor Pazajew was the first space traveler in the world to switch to a space station. The cosmonauts reported an unpleasant, burnt smell in the air. Since a complete air exchange of the station took about 20 hours, the crew had to spend the first night on board the Soyuz. The next day the smell of burning had dissipated and the crew began their work program on board the station.

The first space station crew

Occupation on Soviet postage stamp

The crew moved to the Salyut and shut down all Soyuz systems. The first space station in history went into operation, two years before the American Skylab . The cosmonauts corrected their course and aligned the solar cells with the sun in order to obtain maximum electrical energy.

On the following days the cosmonauts carried out various earth observations and scientific experiments. There were regular video communications with the ground station, during which possible emergency landing areas were discussed in the event that the crew suddenly had to leave the space station. Such an emergency landing might have taken place outside the Soviet Union.

On June 16, the cosmonauts again noticed a strong, burnt smell, the cause of which they could not determine. At times they prepared the Soyuz spaceship for decoupling, but then stayed on board the Salyut. Ten hours after the fire odor first appeared, the air was normal again and the situation was stable. Commander Dobrowolski asked to continue the mission. The State Commission complied with this request the next day, a day of rest for the crew, but ordered that all scientific equipment be switched off. They should gradually be put back into operation in order to be able to determine the cause of the burning smell. On the following day, June 18, all systems were operational again, but there was no longer any burning smell.

For June 20, it was planned to observe the launch of a Soviet N1 missile from space; However, this had to be postponed due to technical problems, so that observation was no longer possible. On June 24th and 25th, Dobrowolski and Pazajew were able to observe the launch of two other Soviet missiles. The N1 then started on June 26th, but got out of control and had to be blown up after 51 seconds.

Over time, the crew was no longer in the best physical and mental condition. Due to the smell incident and unplanned repairs, they had neglected regular training. The rubber bands of the tracksuits, which were supposed to simulate the effects of gravity, were increasingly overstretched. The use of the ergometer , which was supposed to provide movement, was discontinued after only a few days, as its operation caused the entire station to vibrate and the solar cells and communication antennas to vibrate strongly. There were also tensions between Commander Dobrowolski and Wolkow, who was already experienced in spaceflight. The landing was scheduled for June 30th, either at night or just before sunrise. The later time was more favorable if the crew needed medical attention immediately.

On June 26th, the three space travelers had completed all scientific and technical experiments. The remaining days were used for physical training and preparation for the return. It was not possible to get all of the films and experiments in the Soyuz landing capsule back to Earth, so the ground station had to make a selection.

Point by point, the three cosmonauts went through the checklists together with the flight control in order to mothball the space station until the arrival of the next crew. All systems that were not absolutely necessary for automatic operation were switched off.

Landing and death of the crew

The landing was scheduled for June 30 at dawn (June 29 after UT ). The crew should maintain radio contact via shortwave and VHF during the landing and report the opening of the parachute. The cosmonauts should stay in the landing capsule and not open the hatch themselves, but wait for the rescue team and medical staff to arrive, which should take no more than 20 to 30 minutes.

After changing to the return module of the Soyuz spaceship , a warning light indicated that the hatch between the return module and the orbital module was not tightly closed. The crew was only able to lock the hatch after several attempts. After disconnecting, many pictures of Salyut 1 were taken from different distances to document the condition of the space station.

The return, orbital and service modules were separated from one another as planned about twelve minutes after the braking missiles were ignited. A compensation valve opened unexpectedly and the air escaped from the landing capsule. Dobrowolski, Volkov and Pazajew were dead within a very short time. The landing was automatic.

The following table lists the main landing events. The times refer to UTC on June 29, 1971 and differ slightly depending on the source.

18:25 Soyuz 11 decouples from Salyut 1 via Siberia.
21:16 The crew discusses the weather data in the main and emergency landing area with the ground station.
22:35:24 Ignition of the brake rocket
22:38:31 End of the braking maneuver
22:47:28 Separation of the orbital module and return module. In the process, the seal on a valve loosens prematurely. This valve is intended to ensure pressure equalization at a low level after the main parachute has unfolded.
22:49 The landing capsule comes back into radio range . The crew should have reported the disconnection of the orbital module, but the ground station receives nothing.
22:50 The cabin pressure has dropped to practically zero.
22:53 During the re-entry, the radio connection breaks off as planned.
22:54 The landing capsule is located 2200 km from the landing point by the radar.
23:05 Rescue teams on board Il-14 aircraft and Mi-8 helicopters sight the landing capsule, which is falling on the parachute. The crew of Soyuz 11 does not answer.
23:16 Soyuz 11 lands 200 km east of Dzezgaskan, 200 km southwest of Kustanai . At the same time, four helicopters land nearby.
23:18 The rescue team opens the hatch and finds the crew lifeless in their seats.

The misfortune

The investigation

Rescue teams opened the hatch just a few minutes after landing. They found the crew lifelessly strapped into their seats, with Dobrowolski's body still warm. Resuscitation attempts immediately initiated outside the landing capsule were unsuccessful.

Three hours after landing, specialists from Moscow were at the scene of the accident and examined the cabin, the seats and the technical systems. All switches were in the correct position. However, the radios were turned off. The landing capsule hadn't made a particularly hard landing and was completely intact. Both equalizing valves were open as intended, but one had a lower valve lift. While the doctors determined death by suffocation, the engineers were puzzled as to when and why the cabin air could have escaped, because the landing capsule turned out to be tight. An answer to this could only be given by the evaluation of the automatic data recording. After disconnecting the orbital module, telemetry data could no longer be transmitted to Earth, but it was recorded on board with a device called Mir .

The bodies of the three cosmonauts were brought to Moscow on the same day and were laid out there in the house of the trade unions . They were then cremated and the urns were buried on the Kremlin wall on July 3 .

root cause

The investigation showed that about twelve minutes after the brake was ignited, the orbital module was separated from the return capsule as intended, for which purpose explosive bolts were detonated. The investigative commission concluded that the shock broke a seal on one of two pressure equalization valves. This seal should actually have been removed much later by another explosive charge, so that fresh air with external pressure could get into the cabin from a height of a few kilometers. Because the valve was opened at an altitude of 168 km, the cabin air escaped, which led to unconsciousness within 30 to 50 seconds. Two minutes after the orbital module was disconnected, the landing capsule was practically evacuated. The second valve opened as intended when the associated pyrolytic charge was ignited at a low altitude.

The associated handwheel for locking the valve in emergencies was difficult to reach. Only in the event of a ditching, the crew or rescue teams would have had to close it by hand in order to prevent water from entering the capsule via the equalizing valve and flooding the capsule.

The escaping air caused the return capsule to rotate slightly in space, which was compensated for by the automatic ignition of the position control nozzles. The recordings of the engine firings put the experts on the right track, the evidence was fuel residues from the attitude control engines inside the faulty valve, which could only penetrate there in space, since at the time the valve was opened as planned, the engines for position control in space were no longer to be activated.

Effects of decompression on the crew

The crew's medical data was recorded continuously, but not continuously transmitted to Earth. The investigation commission reconstructed the process after the equalization valve had been opened from the recorded data. At the time of the separation of the orbital module, Volkov showed the highest pulse of the three cosmonauts with 120 beats per minute. Pazayev had a pulse rate of 92 to 106, Dobrowolski only 78 to 85. The average value for earlier flights in this phase was 120, the cosmonaut Valentina Tereschkowa had 160 beats. A few seconds after disconnection, the crew apparently noticed the leak. Dobrowolski's pulse rose to 114 and Volkov's to 180. The crew switched off the radios, probably to be able to locate the leak acoustically. Pazayev's breathing rate reached 42 breaths per minute 50 seconds after disconnecting, a typical sign of acute oxygen starvation. No later than 50 to 60 seconds after the separation, deep unconsciousness, shallow breathing and irreversible lethal changes in the vessels and in the brain had occurred in all three cosmonauts. After about 110 seconds, all three cosmonauts suffered cardiac arrest and respiratory arrest. The lactic acid level in her blood had increased tenfold from normal, a sign of extreme stress and acute lack of oxygen.

Just one and a half to two minutes after landing, the rescue forces began unsuccessful resuscitation measures; the crew had been dead for more than 25 minutes at this point.

Why weren't there spacesuits on board?

“I don't want cowards on board my spaceship” was the answer from designer Vasily Mishin when the topic of space suits came up. While the cosmonauts on board the Vostok spaceships naturally wore space suits, this was no longer the case with Vozhod 1 . Since a cosmonaut with a space suit needs much more space than without, three space travelers could only be accommodated in the small Vozhod spacecraft if space suits were not used. While the head of the design bureau, Sergei Korolev , supported this decision, it was criticized by the head of cosmonaut training, Nikolai Kamanin , but also by cosmonauts.

Ilya Lavrov, the designer of the Soyuz life support system, had tried years earlier to convince Korolev that at least oxygen masks were necessary on board. This would have given the crew two or three minutes to react.

Outwardly, the abandonment of spacesuits was justified with the greater security of the Soviet spaceships compared to the American ones.

Could the cosmonauts have prevented the disaster?

Some officials blamed the cosmonauts' inadequate training. Mishin pointed out that closing this valve had even been trained. One of the allegations was that the leak could simply have been closed with a finger. Closing this valve actually belonged to one of the trained emergency procedures - but in the event of a splash, which the cosmonauts would have had several minutes to do.

If the crew had been able to react to the drop in cabin pressure in good time, they would still only have about 25 to 30 seconds to find the open valve and close it before they became unconscious. The exhaust of air could only be heard near Dobrowolski's seat. The shoulder straps were open on Pazayev and Volkov. Dobrowolski's belts were not closed on landing and were twisted into one another. He may actually have attempted the seal using the handwheel on the affected valve. This is also supported by the fact that one of the ventilation valves was not found in the fully open position, but with a 10 mm shorter opening stroke.

Effects

Dobrowolski, Volkov and Pazajew were honored with a state funeral on July 3rd. One of the pallbearers was the American astronaut Tom Stafford . The urns of the three crew members of Soyuz 11 were later buried at the necropolis on the Kremlin wall in Moscow.

The manned Soviet space flight came to a complete standstill. Only a few days earlier, the N1 rocket , which had originally been developed for the Soviet lunar program, had also failed on the third test flight. That could be kept a secret, but before the world public it had to be admitted that a design or operating error had led to the death of the Soyuz 11 crew.

Loss of experimental data

Soyuz 11 was unable to bring all of the films and experimental data back to Earth. The Salyut 1 space station remained unmanned and burned up on October 11, 1971. With it, many scientific results were also lost.

New spacesuit, new spaceship

Subsequent Soyuz crews wore space suits for takeoff and landing . For this purpose, the new Sokol spacesuit was developed by NPP Zvezda under the direction of Gai Sewerin . The associated life support system should fill the cabin with air again in the event of a pressure drop. The third seat fell victim to the increased space requirements for space suits and the life support system. The Soyuz spaceship could only accommodate two spacemen until the Soyuz-T modification was introduced .

The modified spaceship started on June 26, 1972 as Kosmos 496 on an unmanned test flight, followed by another on June 15, 1973 as Kosmos 573 . The first manned launch took place with Soyuz 12 on September 27, 1973. Thus, the manned Soviet space flight had spent a two-year forced break.

Extensions to the next space stations

The 20-day stay of the cosmonauts on board the Salyut showed which facilities were suitable for daily use and where expansions were necessary in the future. The next space stations should therefore also have a device with which liquids could be expelled into space, as well as solar cells and scientific instruments that automatically align themselves to the sun or another target. In addition, a better control unit and better resting places for the crew were necessary.

The next three space station launches took place on July 29, 1972, April 3, 1973 and May 11, 1973, but were all unsuccessful.

Only the launch of Salyut 3 - an Almaz type space station - on June 24, 1974 was successful. Soyuz 14's crew were the first to use the extensions.

Kamanin retires

The head of cosmonaut training, Nikolai Kamanin , had a difficult time even before the flight from Soyuz 11. He resigned from his position on July 8th. He was succeeded by Vladimir Shatalov, the commander of the Soyuz 4, 8 and 10 missions.

The other cosmonauts

During the Soyuz 11 mission, the next team had already prepared to carry out a second visit to Salyut 1 with Soyuz 12. This team consisted of Alexei Leonov, Pyotr Kolodin and Nikolai Rukavischnikow . Except for Rukawischnikow, who replaced Kubasov, it corresponded to the original crew of Soyuz 11. Rukawischnikow had previously been part of the crew of Soyuz 10 as a specialist of the ZKBEM , which had tried in vain to dock with Salyut.

The crew of Soyuz 13 , the feeder flight for the third crew of Salyut 1, were Alexei Gubarew , Vitaly Sevastyanov and Anatoly Voronov . However, it was uncertain whether this team would have been able to fly into space during the life of Salyut 1.

With the death of the Soyuz 11 crew, all plans were put on hold for the time being.

After the resumption of space flights in September 1973 there were only crews with two instead of three space travelers until the Soyuz T-3 took off. Rukavishnikov did his next space flight with Soyuz 16 in December 1974 , Gubarev flew in January 1975 with Soyuz 17 to Salyut 4 , Sevastyanov in May 1975 with Soyuz 18 to the same destination.

The suspicion of tuberculosis in Kubasov was not confirmed. He was reassigned to his commandant Leonov. You took part in the Apollo-Soyuz test project , the first international space flight, in July 1975 with Soyuz 19 . Kolodin and Voronov never made a space flight.

See also

literature

Web links

Commons : Soyuz 11  - collection of pictures, videos and audio files

Individual evidence

  1. ^ A b Asif A. Siddiqi: Challenge to Apollo: The Soviet Union and the Space Race, 1945-1974 (=  The NASA history series . SP-4408). NASA, Washington 2000, ISBN 1-78039-301-6 , pp. 776–777 (English, nasa.gov [PDF; 362.9 MB ; accessed on February 6, 2021]).
  2. ^ Asif A. Siddiqi: Challenge to Apollo: The Soviet Union and the Space Race, 1945-1974 (=  The NASA history series . SP-4408). NASA, Washington 2000, ISBN 1-78039-301-6 , pp. 780 (English, nasa.gov [PDF; 362.9 MB ; accessed on February 6, 2021]).
  3. ^ Boris E. Chertok : The Moon Race . In: Asif Siddiqi (Ed.): Rockets and People (=  The NASA History Series . SP-4110). NASA, Washington 2011, ISBN 978-0-16-089559-3 , chap. 16 , p. 400–401 (English, nasa.gov [PDF; 6.3 MB ; accessed on February 6, 2021] Russian: Лунная гонка . 1999.).
  4. ↑ a b Boris E. Chertok : The Moon Race . In: Asif Siddiqi (Ed.): Rockets and People (=  The NASA History Series . SP-4110). NASA, Washington 2011, ISBN 978-0-16-089559-3 , chap. 16 , p. 403–404 (English, nasa.gov [PDF; 6.3 MB ; accessed on February 6, 2021] Russian: Лунная гонка . 1999.).