In analysing the actions of the Soyuz 11 cosmonauts during the decompression to assess whether they might have saved themselves, there are two basic approaches. Mishin and the TsKBEM engineers concluded that the crew should have been able to halt the leak - but they had panicked and failed to identify the source of the leak in time. But General Kamanin and the military cosmonauts at the TsPK thought that the decompression occurred so rapidly that the crew had no real chance of manually closing the shutter on the leaking valve.
Of the official sources, Kamanin provided probably the most realistic description of the fateful events. As he wrote in his diary, following the braking manoeuvre the cosmonauts felt the onset of deceleration - which meant that the ship had begun its descent:
Aboard, everything is normal. However, the cosmonauts, remembering their recent difficulty with the transfer hatch, carefully monitored the pressure in the cabin. A bang is heard - there is the separation of the modules. But what is this? The pressure in the cabin begins rapidly to fall. ... Decompression! After unfastening from his couch, Dobrovolskiy goes to inspect the hatch. It is airtight, but the pressure continues to fall. They can hear the whistle of air venting to space. Because of noise from the transmitters and receivers, they cannot trace the source of the whistle. Volkov and Patsayev unfasten their shoulder straps and switch off the radio apparatus. The source of the whistle is above the centre couch - where a vent valve is located. Dobrovolskiy and Patsayev attempt to close the valve, but because they are weakened they fall back to the seat. As he loses consciousness, Dobrovolskiy manages to fasten the waist lock of his entangled straps.
Mishin argued that once the crew had realised that one of the valves had opened prematurely, they should have blocked the flow by placing a thumb over the inlet.3 Some sources have pointed to a bruise on Dobrovolskiy's thumb as evidence that he had indeed attempted to do this. Another source says the bruise was on Patsayev thumb, although this may actually have been a reference to his facial bruise. Mishin never accepted that the crew could not have saved themselves. To the end of his life he insisted that if only they had been better trained then they would have reacted properly, and therefore probably have survived: "How can you describe the deaths of great and brave people - a disaster which caused such pain to their relatives? It is more painful to know that it was avoidable. During separation, the explosive bolts generated a force that was too strong and the ball left its nest, opening the valve prematurely. The cosmonauts could hear the air whistling. Patsayev tried to close it using his thumb, but failed. There was a manually operated shutter with which it was possible fully to protect the cabin, but they either forgot it, or did not know, or missed it in their training.'' In another interview, Mishin again criticised the crew: "During the decompression, the air would have escaped to space at such a high speed that the men had to have heard the whistling - a signal of imminent disaster. It was necessary to unfasten the belts, to stand up and to shut the valve. They could block the valve even using a thumb! . . . But the cosmonauts were disoriented. . . . Perhaps they were lost. . . . Patsayev seems to have realised what was the matter. He unfastened from his couch, but did not have time to stand up.''
While Mishin was trying to blame the crew and to justify the spacecraft's design, representatives of the TsPK thought differently. In contrast to Mishin, Kamanin was confident that the crew fought to save their lives right to the end: "Is it possible to accuse them of not knowing how 'to plug the hole in the ship by finger'? We cannot presume this to be feasible at all, as no one has yet tried to do it. Indeed, outside the ship is the deep cold of the vacuum of space, which causes the instantaneous boiling
3 In making this remark, Mishin gave the impression that he expected that a cosmonaut would hold his finger in place to stem the air leak right through the re-entry process, until the capsule was in the atmosphere. However, the real value in interrupting the leak in this manner would have been to buy the time required to close the manual shutter on the valve. Yet there was no tank to replenish the lost air.
of the blood. I think even in normal conditions it would be hard to hold a finger in open space for a period as brief as several seconds. In addition, the crew had first to locate the source of the decompression and then, 'after plugging the hole by thumb', to retain the hermetic seal of the cabin for 15-17 minutes during which they would be subjected to the increasing deceleration loads of the descent.''4
Commenting on Mishin's claim that a man could have blocked the valve using a finger, Dr. Yevgeniy Vorobyev pointed out that in such a rapid decompression the state of consciousness would have been diminished after 20 seconds. ''To unbuckle, locate the hole under the cover and block this in 20 seconds would be unrealistic. It would have been necessary to train to do so. We tested the possibility of closing the valve manually, in the case of a splashdown. Even in a calm situation, this operation took 35-40 seconds. Thus, they had no chance of surviving.''
General Shatalov openly condemned Mishin for his ongoing efforts to blame the crew. Cosmonaut Leonov tested manually closing the valve of the Soyuz simulator in the TsPK, taking 52 seconds, which was four times longer than the time available to the Soyuz 11 crew.
Although further explanations were given in Chertok's memoirs, colleagues of the Soyuz 11 crew - in particular Yeliseyev, Kubasov, Shatalov and Leonov, together with Viktor Patsayev's wife Vera - contributed the most to a full understanding the tragedy.
Aleksey Yeliseyev's insight into the valves leads to the inevitable conclusion that the tragedy ought never to have occurred!
As noted, each valve had both an automatic and a manual shutter. However, when the designers devised the valve no one considered the possibility that the automatic shutter might open spontaneously. In accordance with instructions, prior to launch both shutters (automatic and manual) on valve No. 1 were required to be closed - in the mode 'closed-closed'. On the other hand, on valve No. 2 the automatic shutter was to be closed and the manual shutter open - in mode 'closed-open'. What does this mean? During the descent, four pyrotechnic charges were to open the automatic shutters on both valves at an altitude of 5 km. However, because the manual shutter on valve No. 1 was closed, air would flow into the cabin only through valve No. 2, whose manual shutter was already open. As noted, the reason for there being a pair of valves was to ensure that in the event of a splashdown in which water leaked into the module through valve No. 2, there was another valve on the opposite side which would allow in air - the research cosmonaut seated near valve No. 2 would close its manual shutter to halt water penetration while the commander opened the manually operated shutter on the valve positioned directly above his couch. However, during the preparation of the ship there was a mysterious change to the procedure! Instead of being 'closed-closed', valve No. 1 was actually set 'closed-open'; and instead of'closed-open', valve No. 2 was set 'closed-closed'. As the valves were identical, the technicians did not pay special attention to this change.
4 Kamanin has interpreted Mishin's remark about a cosmonaut stemming the air leak by holding his thumb over the hole literally, and is criticising the expectation that this could have been sustained as the deceleration loads increased and forced the crewman back into his couch. In fact, if all that was intended was to buy time to close the manual shutter in the valve, then this criticism of the idea does not apply.
Top: Cosmonaut Lazaryev works on the hatch inside the Soyuz simulator, with one of two valves installed in the vicinity. Three bottom photos show the opening of one of the valves (left), the control for the manually operated shutter and the ventilation switches.
Valve No2 Valve No1
Electric lino with two pyrocharges in the ball of automatic shutter
Manual shutter [closed position!
A simplified depiction of the operational structure of the two ventilation valves.
As the explosive bolts were fired to separate the orbital module, the shock caused the automatic shutter on valve No. 1 to open. This valve was positioned very near to two of the bolts, and thus was exposed to the greatest stress by the explosive action. Since the manually operated shutter had been left open, air was able to leak to space. A detailed analysis of the telemetry recorded by the 'black box' established that the automatic control system had fired the attitude control thrusters to counter the force of the air venting at speed through this valve. After inspecting the seal of the hatch, the cosmonauts quickly realised that the automatic shutter had inadvertently opened in one of the valves. Knowing that both shutters on valve No. 1 were supposed to be closed, they directed their attention to valve No. 2, which they believed had been set to 'closed-open' and was 'open-open' as a result of the shock of firing the bolts, but in fact it was still hermetically closed. Patsayev's effort to close the manual shutter of valve No. 2 was foiled by the fact that it had already been closed prior to launch! Realising that valve No. 2 was closed, Patsayev or Dobrovolskiy set about closing the manual shutter of valve No. 1, but managed only to partially do so before losing consciousness.
According to Yeliseyev the cosmonauts forgot, or in panic missed the fact that the order of the valves had been changed! He said: ''If they had just remembered this! If even they did not recall, but they had begun to close both valves just in case, they would have saved themselves.'' The revision to the manually operated shutters was also noticed by Kubasov, who, in addition, noted another important detail: ''At the cosmodrome, according to instructions, the manually operated shutter on one of the two valves is open and on the other is closed. This is specified in both the onboard documentation and the documentation of the manufacturer. But on Soyuz 11, ... according to the onboard documentation the valve that prematurely opened ought to have had its manually operated shutter closed, and in the documentation of the manufacturer it should have been open.'' Thus we see that valve No. 1 had state
Valve No2 Valve No1
A simplified depiction of the operational structure of the two ventilation valves.
'closed-closed' in the onboard documentation, and the crew did not simply forget or in a blind panic miss the order of the open/closed shutters. They firstly tried to close valve No. 2 because in their documentation its manually operated shutter was specified as being open, but in reality it was closed! As in the case of the Soyuz 1 tragedy, the technicians who prepared the spacecraft had not followed the rules!
Vladimir Shatalov, who was member of the State Commission which investigated the Soyuz 11 tragedy, reported some details of his inspections related to the lack of technical discipline in the installation of the valves:
The most likely cause was a design fault or omission during the installation of the valves during the assembly of the spacecraft. Both valves had to be torqued to the certain level by using a special tool, even though access to the valves was problematic. . . .
During an inspection, it was found that for both valves the screw had not been sufficiently tightened, and the ball was free to jiggle about. When they examined the valves on already flown craft, including my Soyuz 10, it was noticed that the screws were torqued differently. The required force was 50 kg, but some of the descent modules had valves torqued at 30 kg, some at only 20 kg, and one had valves whose screws were barely tightened! There were no spacecraft already flown in space with valves torqued to the proper degree. I could not believe this. Well, it was an accident waiting to happen!
In the book Two Sides of the Moon published in 2004, Aleksey Leonov states he was in the communication centre in Kaliningrad for the undocking. As the crew worked through the checklist, he advised them to close the shutters of both valves, but to remember to reopen one once the parachute had deployed.
"Make a note of it in your logbook,'' I instructed them.
Although this deviated from the flight regulations, I had trained for a long time for the mission they were flying, and in my opinion this was the safest procedure. According to the flight programme the vents were [to start closed] and then open automatically once the parachute had deployed after re-entry. But I believed there was a danger, if this automatic procedure was followed, that the vents might open prematurely at too high an altitude and the spacecraft [would] depressurise.
It seems the crew did not follow my advice. Unfortunately, my intuition proved right. . . .
The loss of the Soyuz 11 cosmonauts was a terrible blow to the morale of the whole corps. Everyone understood that we were in the business of testing spacecraft, and the deaths of these three men undoubtedly saved the lives of later crews, because of the substantial modifications made, but their loss was a tragedy. Not only was I deeply saddened by what had happened, but I was frustrated, too. Had I been allowed to fly in their place I am sure my crew would have survived.
Leonov also wrote that he never told anyone that the crew had failed to follow his recommendation. Many years later, Vera Patsayeva, who worked in the TsNIIMash and had access to the radio exchanges, ''recognised the crew's tragic mistake of not following my advice and made that fact public''. He tried to avoid the children of the lost crew: ''I could not bear to look into their eyes. Even though it was not my fault, I blamed myself for what had happened. It was not until much later that the children learnt how desperately I had tried to avert the tragedy.''5
Leonov also noted that the cardiogram data showed that Volkov, who remained in his couch, died 80 seconds after the decompression, Patsayev after 100 seconds and Dobrovolskiy after 2 minutes. Leonov's claim that if he had been in command then his crew would not have succumbed to such a failure was contradicted by Kubasov in an interview with Novosti kosmonavtiki, who, after analysing what they would have done, had concluded that death was inevitable.
In contrast to Mishin, who insisted that the crew had been at fault, the strongest criticism of the cosmonauts' action ever to be made by any representative of the Air Force was Leonov's claim that they had not accepted his advice to close both valves and reopen one after the parachute had deployed. On the other hand, this advice was contrary to the rules. It would have protected against a valve opening prematurely, but to have required that a valve be opened manually would have placed the crew at risk of asphyxiation in the event of stronger than expected dynamic loads during the reentry rendering them unconscious - it was, after all, to preclude this outcome that the valves were designed to work automatically. But it indicates that Leonov's crew had trained to perform re-entry differently to their backups. Furthermore, in training Leonov seems not to have described this alternative procedure to Dobrovolskiy.
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