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Shown at the funeral of the
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Shown at the funeral of the Soyuz-11 crew in early August 1971 at Red Square are (left to right) Boris Chertok, Yuriy Semyonov, and Vakhtang Vachnadze. Over the five days from 25 through 30 June 1971, fate had dealt us three blows: on the 25th, the death of Isayev; on the 27th, the failure of N-1 No. 6L; and on the 30th, the death of the Soyuz-11 crew. There was no doubt that throughout July and August our staff would be given a shaking by at least two independent commissions: one for the N-1 and the other for the Soyuz. After a brief hesitation, the Politburo added to Keldysh’s concerns. They made him chair- man of the government commission investigating the causes of the death of the Soyuz-11 crew. They appointed Georgiy Babakin deputy chairman. Members of 396
The Hot Summer of 1971 the commission were Afanasyev, Glushko, Kazakov, Mishuk, Grushin, Shcheulov, Frolov, Burnazyan, Shatalov, and Tsarev (commission secretary). 51 Keldysh convened the first commission meeting on 7 July. Opening the meeting, Keldysh announced that in addition to the members of the commis- sion appointed by the administration, from TsKBEM he had invited Mishin, Bushuyev, Chertok, Tregub, Shabarov, and Feoktistov, and—at the request of the Ministry of Defense—Karas. “We are obliged to submit a report to the Central Committee and Council of Ministers within two weeks,” said Keldysh. He went on to say that that morning he had been invited to the Politburo along with Smirnov and ministers Afanasyev and Dementyev. “After expressing his sorrow over what had happened,” continued Keldysh, “Leonid Ilyich asked that I tell you that under no circumstances has this given rise to any mindset for curtailing operations. We need to figure out as quickly as possible what caused this and continue the program of flights using long- duration space stations. Over the past few days various groups created to assist our commission have performed a great deal of work, and therefore, we shall begin by listening to what these working groups managed to find out.” Mishin was the first to report. He spoke in detail about the modifications and how the Soyuz-11 7K-T vehicle differed from its predecessors. Since November 1966 a total of 19 vehicles had been launched. Of these, 17 were 7K-OK models and two were 7K-Ts. The last one, 7K-T No. 32, differed from the previous one [Soyuz-10] only in terms of its modified docking assembly. Before descent, no in-flight off-nominal situations were recorded on vehicle No. 32. All operations for descent proceeded normally until the moment of separation. According to the data from the Mir recorder, at the moment of separation the pressure began to drop in the Descent Module. Over a period of 130 seconds the pressure dropped from 915 to 100 mil- limeters of mercury. Keldysh interrupted Mishin: “The Commission needs to know by all means about all abnormalities, not only on the vehicle but also on the station. We need to prepare a list of all, I repeat, all glitches without exception. The entire prehistory needs to be clear to us. In particular, explain: why did we begin flights into space in spacesuits and then do away with them so quickly?” 51. These men represented various branches of the Soviet space program including industry (S. A. Afanasyev, V. A. Kazakov, A. I. Burnazyan, and A. I. Tsarev), designers (V. P. Glushko and P. D. Grushin), the Air Force (M. N. Mishuk and S. G. Frolov), the Rocket Forces (V. I. Shcheulov), and cosmonauts (V. A. Shatalov). 397
Rockets and People: The Moon Race Mishin made a show of instructing Tregub and Feoktistov to prepare posters with a list of all glitches by tomorrow morning. He must have been very uncomfortable. First, because the guilty party in the tragedy, the news of which had spread throughout the world, was TsKBEM, and consequently, he, its boss and chief designer. Second, this disaster came on top of the N-1 failure, for which TsKBEM was ultimately also at fault. Each accident had specific responsible parties. The blame for each of them might be different. The fact that everyone collectively didn’t know, didn’t foresee, didn’t under- stand something served as a general excuse. That’s the very learning process that Korolev used to talk about. These arguments come in handy for a lawyer if a case were to go to trial. But this was a trial where each person was his own investigator, prosecutor, judge, and lawyer. Even the aim of the members of the Commission was not to look for the guilty party, but to understand what caused the disaster. Each of them had his own failure. And each understood full well that there were no evildoers or slovenly individuals here. There were flaws or unexplored spots in a large system. They needed to be hunted out. It was difficult for Mishin to answer Keldysh’s question about why we had done away with spacesuits. Korolev had made that decision personally before the launch of Voskhod [in 1964]. It was also impossible to fit three men in spacesuits in the Soyuz Descent Module. When Korolev was alive only Kamanin had come out strongly in favor of spacesuits. But chief planner of piloted vehicles Feoktistov had himself flown without a spacesuit with Komarov and Yegorov. He actively supported Korolev’s initiative. Mishin had nothing directly to do with abandoning spacesuits. No problems had arisen with maintaining pres- sure integrity during a single one of the Vostok, Voskhod, and unpiloted and piloted Soyuz flights. Somehow demands to reinstate flights in spacesuits were of their own accord forgotten. Mishin set forth some scenarios, supporting them with posters that Feoktistov put up. “After landing, the Descent Module was checked out and no damage was found. Depressurization could have occurred due to two causes. The first is the premature actuation of a breathing vent valve. In this case the pressure should fall according to the upper curve. The second possible cause is an improper hatch seal. The curve of the calculated pressure drop when the valve is opened precisely coincides with the recording of the actual pressure drop after separation. In addition to the coincidence of the calculated and actual drop curves, we have evidence from the descent control system (SUS). The recording of the SUS behavior shows the presence of off-nominal disturbance. Judging by the magnitude and character, this disturbance coincides with the calculated value for the egress of air from the opening formed when a breathing valve is opened.” 398
The Hot Summer of 1971 Grushin interrupted Mishin, trying to understand why this breathing vent was necessary in the first place. “Is the valve closed on the launch pad? It’s closed. Is it closed throughout the entire flight? It’s closed. Is it closed during descent? It’s closed. And you only open it at an altitude of 2 or 3 kilometers above Earth. You open up the hatches anyway right after landing. You’ve outsmarted yourself here somehow.” Unintelligible explanations began as to why this valve was necessary. To be perfectly frank, they were very unconvincing and contradictory. The discus- sion that had started became even more complicated after it was determined that in addition to this [breathing] valve, which is opened automatically by an explosive cartridge, there is also a manual butterfly valve. It was provided in the event of a water touchdown. By turning the handle of this valve, it is possible to block off the opening formed by the ill-fated breathing vent valve so that water doesn’t get into the Descent Module. Mishuk asked how the electrical scenario had been analyzed and why no one was talking about it. I answered that both the telemetry recordings and the autonomous recorder data had been thoroughly examined. There were no indications that a false premature command had been issued to the explosive cartridge opening the valve. An analysis of the Mir recordings showed that pressure integrity was lost at the moment of separation of the Descent Module from the Habitation Compartment. The pressure drop curve corresponded to a hole size equal to the cross section of a single valve. In fact there were two valves: one was a feed valve and the other a suction valve. If a false command had passed, then both valves would have opened right away: electrically, they were in the same circuit. The command to open two valves passed nominally, as it was supposed to at a safe altitude. According to the findings of specialists from the Scientific-Research Institute for the Operation and Repair of Aviation Technology (NIIERAT) (that’s the clever title worn by the Air Force institute that holds a monopoly in the investigation of all aviation disasters), the explosive cartridges were not actuated in a vacuum, but at an altitude corresponding in time to the issuance of a nominal command. 52 But by this time one valve had already opened without the electrical command. “In your opinion, what kind of evil spirit could have opened it at an alti- tude of 150 kilometers?” asked Kazakov. “Let’s not get carried away prematurely with one scenario,” intervened Keldysh; “we need to discuss all of them on equal terms. I propose that we listen to Shabarov and medical science.” 52. NIIERAT—Nauchno-issledovatelskiy institut ekspluatatsii i remonta aviatsionnoy tekhniki. 399
Rockets and People: The Moon Race Shabarov reported on the results of the analysis of the data from the Mir recorder, which for us performed tasks similar to a “black box.” In aviation disasters recovery crews hunt for the “black box” among the charred remains of the airplane, and we removed it safe and sound from a Descent Module that had executed a normal landing. “The separation process lasted just 0.06 seconds,” reported Shabarov. “At 0147 hours 26.5 seconds, a pressure of 915 millimeters of mercury was recorded in the Descent Module. One hundred fifteen seconds later it had dropped to 50 millimeters and continued to fall. During entry into the dense layers of the atmosphere the operation of the SUS was recorded. G-loads reached 3.3 units and then decreased. But the pressure in the Descent Module began to slowly increase: there was an inflow of air from the external atmosphere through the open breathing vent. Here on the chart is the command to open the valve. We see that the intensity of the inflow has increased. This corresponded to the opening of the second vent on command. Analysis of the Mir recordings confirmed the scenario of the opening of one of the two vents at the moment the vehicle modules separated. The temperature on the Descent Module’s structural ring, not far from the hatch rim, reached 122.5°C [252.5°F]. But this was due to the general heating upon entry into the atmosphere.” “Before we go any further, let’s hear the results of the medical investiga- tions,” proposed Keldysh. Burnazyan made the report. “During the last days of the flight the physical condition of the cosmonauts was good. They had been taking invigorants. They did three hours of general physical conditioning exercises every day. Dobrovolskiy had a resting pulse rate of 78 to 85. His blood pressure was normal. Volkov was more emotional. His pulse was high, in general; before separation of the vehicle modules his pulse reached 120. Patsayev’s pulse was from 92 to 106. Based on the experience of other cosmonauts, pulse rates reached as high as 120 during peak periods, and Tereshkova’s even went up to 160. During the first second after separation, Dobrovolskiy’s pulse rate increased immediately to 114, and Volkov’s to 180. Fifty seconds after separation, Patsayev’s respiration rate was 42 per minute, which is characteristic for acute oxygen deprivation. Dobrovolskiy’s pulse quickly dropped and his breathing stopped at about that time. This was the initial period of death. At the 110-second mark, no pulse and no breathing is recorded in all three of them. We believe that death occurred 120 seconds after separation. They were conscious for no more than 50 to 60 seconds after separation. During that time, evidently, Dobrovolskiy wanted to take some sort of action, judging by the fact that he had thrown off his safety belts. “Seventeen top specialists were called in for the autopsy. Subcutaneous hemorrhaging was found in all three cosmonauts. Air bubbles, like fine sand, 400
The Hot Summer of 1971 had gotten into their vessels. All of them had hemorrhaging in their middle ear and ruptured eardrums. Stomachs and intestines were bloated. Gases—nitrogen, oxygen, and CO 2 —dissolved in the blood—seethed under the acute low pres- sure. The gases dissolved in the blood, after being transformed into bubbles, occluded the vessels. When the pericardium was opened, gas escaped: there had been air plugs in the heart. The vessels in the brain looked like strings of beads. They were also clogged with air plugs. Also indicative of the enormous emotional stress and acute oxygen deprivation is the amount of lactic acid in the blood—it was 10 times higher than normal. “A minute and a half after touchdown, resuscitation attempts began. They continued for more than an hour. It is obvious that given this degree of injury no resuscitation methods could save them. In the history of medicine, and very likely not just medicine, there are no comparable examples known, and nowhere have experiments been conducted, not even on animals, to determine the body’s reaction to such a regime of pressure reduction—from normal atmo- spheric pressure to virtually zero within dozens of seconds. There have been cases of depressurization of flight suits at altitudes in excess of 10 kilometers. In these cases the pilot lost consciousness from lack of oxygen, but when the airplane descended he regained consciousness. In this case, irreversible processes occurred over the course of dozens of seconds.” Burnazyan’s calm report made a harrowing impression. Mentally plac- ing themselves into the Descent Module, everyone tried to imagine how the cosmonauts felt during those first seconds. The excruciating pain throughout their bodies prevented them from thinking and comprehending. Certainly they heard the whistle of escaping air, but their eardrums quickly burst and silence set in. Judging by the speed of the drop in pressure, they were able to actively move and attempt to do something for perhaps the first 15 to 20 seconds. The government commission for the investigation of the causes of death of the Soyuz-11 crew broke into groups according to scenario and areas of expertise. Three days later another plenary session of Keldysh’s commission took place. This time the leaders of the investigative groups had already reported. With regard to Mishin’s comment that the cosmonauts “could have figured out by the sound to plug the opening with their finger,” Yevgeniy Vorobyev officially declared that given that rate of pressure drop they would have lost consciousness in 20 seconds. “To figure out what had happened, unfasten the safety belts, and find the hole beneath the interior paneling within 20 seconds is unrealistic,” Vorobyev said. “They would have had to have been trained to do that beforehand. We tested the ability to close the breathing vent using the manual drive, which is done in the event of a touchdown in water. This operation takes 35 to 40 401
Rockets and People: The Moon Race seconds under calm circumstances. So they had no chance of saving themselves. Clinical death occurred 90 to 100 seconds later simultaneously in all of them. “Meanwhile we affirm that 23 days in space could not have caused their condition to deteriorate. We affirm that subsequently we will give our approval for cosmonauts to stay on the station for 30 days.” “There can be no discussion of how many days until we establish the cause of this incident and completely eliminate the probability of it happening again,” concluded Keldysh, closing the meeting. The root cause of the depressurization of the Descent Module was not immediately apparent, and the fierce arguments continued. Now it was difficult to find the individual who was the first to come out with the scenario that became the leading hypothesis during all subsequent investigations con- ducted per the commission’s decisions. The two compartments—the Descent Module and the Habitation Compartment—were firmly linked together. The surfaces of the Descent Module and Habitation Compartment docking rings were held together with eight pyrobolts. During assembly the installers tightened the compartments together using special torque wrenches. The operation was critical and was monitored not visually, but in a special pressure chamber. The interface must be airtight. According to another requirement, the Habitation Compartment and Descent Module must instantaneously separate along this interface before landing. How was this done without unscrewing the tightening bolts? Very simply. The bolts needed to be pulled apart by an explosion. Each bolt had a powder charge, which was detonated using explosive cartridges triggered by an electrical command from the sequencer. All the pyrobolts were detonated simultane- ously. In a vacuum, a shock wave can only spread through metal. Its impact is so strong that a valve mounted in the same structural ring as the explosive bolts could spontaneously open. That’s such a simple scenario. We began performing experiments at our factory and at NIIERAT. Valves were subjected to stability tests under exposure to large impact loads. The Politburo-imposed two-week deadline for the commission’s work passed, but dozens of experiments did not bring the proof that was so indispensable. The valves had not opened due to explosive shock. At Mishuk’s suggestion, several valves that had intentional manufacturing defects were assembled at the factory. From a quality control standpoint, they were obvious scrap parts. But even they wouldn’t yield to explosive shock. Out of frustration, Keldysh, who almost every day reported to Ustinov about the progress of the work and once a week to Brezhnev, proposed that the Descent Module and Habitation Compartment separation process be simulated in the large pressure chamber. It was assumed that during the simultaneous detonation 402
The Hot Summer of 1971 of all the pyrobolts in a vacuum, the shock wave spreading only through metal would be more powerful than at normal atmospheric pressure. “We’ll delay the report a week, but we’ll have a clear conscience: we did everything that we could,” Keldysh said. One of the organizers of this very difficult experiment was Reshetin—at that time chief of the design department that had been responsible for developing the Descent Module. Today, Andrey Reshetin, a doctor of technical sciences, professor, and my colleague in the core department of the Moscow Physical Technical Institute, recalls, “We conducted this complicated experiment in the large pressure chamber at the Cosmonauts Training Center in Star City. The Descent Module and Habitation Compartment mockups were held together with standard pyrobolts. The breathing vents were intentionally installed with manufacturing defects, which supposedly could have taken place during their production. The pyrobolts were detonated simultaneously according to the con- figuration used in flight. The experiment was conducted twice. The valves did not open. The true cause of the opening of the breathing vent during separation of the Soyuz-11 Descent Module and Habitation Compartment remained a secret.” Instead of the two weeks set aside for the commission and everyone par- ticipating on it, a month passed. Over the course of this month they prepared radical proposals guaranteeing the cosmonauts’ safety in the event of Descent Module depressurization. Gay Severin, who was in charge of the Zvezda Factory, made use of his considerable aviation experience and quickly developed the new Sokol (Falcon) spacesuits. The number of crewmembers would have to be reduced from three to two. A life-saving oxygen unit occupied the place of the third cosmonaut. In the event of the Descent Module’s depressurization an automatic control was trig- gered, starting the flow of oxygen from the tanks. This unit would allow the crew to survive for the amount of time required for descent even without spacesuits. To Ilya Lavrov, the most emotional of our life-support systems developers, the cosmonauts’ deaths were a profound personal tragedy. “I’m tearing myself up over the fact that I went along with Feoktistov and Korolev to do away with spacesuits. I wasn’t able to persuade them to install simple oxygen units with masks, which were widely used in aviation. Of course, given such a vacuum, a mask wouldn’t have saved anyone, but it would have prolonged their lives by 2 or 3 minutes. Perhaps, that time would have been enough to close the opened breathing vent using the manual valve.” Lavrov and Boris Penek’s electrical engineers spent six months developing an emergency oxygen system. In addition to all sorts of other measures, they introduced a quick-closing manual drive for the breathing vents. “And as far as the final wording of the causes is concerned,” said Keldysh at the commission’s final meeting, “we will consider that the opening of the 403
Rockets and People: The Moon Race valve was the result of a shock wave spreading over the metal of the structure. This is a probabilistic phenomenon. In order to achieve it under real conditions it would be necessary to conduct dozens or hundreds of experiments. After those measures, which will be implemented at the recommendation of our commission, evidently, it will no longer make sense to continue these costly pyrobolt firings in pressure chambers.” And that was that. However, when we had estimated how much weight it would take for all the projected measures, we wept. In order to maintain the Soyuz spacecraft’s weight limit, the planners persuaded Mishin to take off the solar arrays. The argument was simple: from now on the Soyuz would be just a transport vehicle for delivering a crew to the orbital station and returning it to Earth. Soyuzes were no longer needed for independent long-duration flights. After docking with the DOS, the Soyuz’s chemical batteries would be charged from the DOS power system before returning to Earth. Modification, however, dragged on. It wasn’t until 26 July 1972 that a Soyuz under the name Kosmos-496 executed an unpiloted flight. After a series of failures with orbital stations, one more unpiloted Soyuz was tested on 15 July 1973, under the name
a piloted flight of the new space- craft take place. In the press it was referred to as the transport Soyuz. Vasiliy Lazarev and Oleg Makarov were the first cosmonauts to test out this Soyuz after the death of Georgiy Dobrovolskiy’s crew. They did not fly until September 1973 on Soyuz-12. Soyuzes continued to be operated with a two-man crew until 1981. 53 Over that period of time 18 piloted flights took place.
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