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NPO Energiya cosmonaut Vladimir Aksenov
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NPO Energiya cosmonaut Vladimir Aksenov inscribed this picture of himself while he was in space during his Soyuz-22 flight in 1976. 50. TsUKOS—Tsentralnoye upravleniye kosmicheskikh stredstv (Central Directorate of Space Assets)—was the official name of the Soviet “space forces.” 507
Rockets and People: The Moon Race took place showed that the computer was performing dynamic monitoring of the approach parameters and predicting their changes. The computer prognosis differed from the actual motion. Consequently, the computer decided that the process was abnormal, issued an “emergency” command, and shut down the automatic control system. The computer was not the culprit. It was a human error, this time committed by representatives of a new profession—programmers. The control algorithms required a greater rendezvous velocity than was actually the case. It was mandatory that any changes in the drawings of a rocket, of a space- craft, or in electrical circuits be documented in “change notices.” Depending on the causes and consequences, these notices had to be signed by the authors, managers, lead designers, and—in acute situations—the chief designer, too. Changes in the software, on the other hand, could lead to much more significant consequences than changes in the electrical circuitry or design. For the design and circuitry, there were sets of drawings and technical documenta- tion, which were accounted for in accordance with all the stringency of state standards. The originals were stored in archives, and each change was strictly recorded in accordance with the rules of technical documentation management. Something intangible, unaccounted, incomprehensible—software—broke into this strict order, which had been in place practically since the times of the artillery of Peter I. This prompted some heated conversations between Yeliseyev’s and Legostayev’s services. “We must train the TsUP operators and cosmonauts using documents that are accounted for—drawings, diagrams, descriptions—which exist for all the vehicle’s systems,” Yeliseyev said. “But when it comes to motion control, they tell us that now we need to study algorithms and programs rather than instruments. We are prepared to do this, but show them [to us]. It turns out that in the best-case scenario they are in the developers’ notebooks, and each one of these idea men is storing all the changes in his own memory. That’s fine if the person isn’t off on a business trip or on vacation, and without him no one can remember the ‘patch’.” These were more or less the completely valid grievances that Yeliseyev mentioned to me. It took two years before some order was brought into this system. During the first years of on-board digital computers, the authors of algorithms and programs were themselves the record-keepers and executors of changes intro- duced into the computer memory. There were a lot of arguments, turmoil, and all sorts of incidents associated with this. Software was supposed to be updated, supplemented, and improved based on observations after each flight. Soyuz T-3 and Soyuz T-4 had been launched to Salyut-6, and Soyuz T-5 launched to Salyut-7. The computer on Soyuz T-6 once again decided to give notice that it 508
People in the Control Loop was high time to bring strict order to the data that the whiz-kid programmers were using to try to “train” it. Cosmonauts Vladimir Dzhanibekov, Aleksandr Ivanchenkov, and Frenchman Jean-Loup Chrétien flew on the Soyuz T-6 launched on 24 June 1982. Dozens of correspondents and foreign guests, including the French ambassador and his diplomatic entourage, filled the visi- tors’ gallery at TsUP. There was no need to say anything about our brass. After all, the first Frenchman in the history of cosmonautics was being launched into space on a Soviet spacecraft. I was at TsUP following the course of the approach process on the moni- tors with those directly participating in this crucial historic event. Groups of approach and docking specialists had moved their workstations out of the main control room into a separate room on the second floor so that they wouldn’t disturb others and others wouldn’t disturb them. The crew switched on the automatic approach mode during the 17th orbit after executing the two-burn maneuver prescribed by the ballistics experts for the vehicle to make a safe entry into Igla’s coverage zone. At 2009 hours, the first information appeared on the monitors: “Target availability signal received; range 11.4 kilometers; approach velocity 18 meters per second.” Ten minutes later the on-board digital computer requested crew permission to execute a braking burn. The crew gave permission from its con- sole. After that the computer acted according to the algorithm loaded into its memory, in concert with the information received from Igla. Upon receiving its commands, the Chayka control system turned the spacecraft’s pitch by 90° and fired the engine to reduce the line-of-sight angular rate to zero. Now it executed a reverse turn to put the spacecraft into the initial state and then to swing around to fire a second correcting burn. At 2026 hours, at a range of 1.4 kilometers, they began the second turn in the yaw angle. Meanwhile, the lock-on mode strayed. The Igla antennas were unable to maintain lock-on at wide angles. But the on-board digital computer kept this in mind. Upon receiving the computer’s command, the engine fired at a range of 960 meters. The approach velocity slowed to 3.3 meters per second. The computer did not “forget” to issue the command for a turnaround. In so doing, communication was restored via Igla. “So that’s how we rendezvous now!” someone standing behind us mar- veled, with bad timing. “Remember, in Yevpatoriya we only found out from the films that the SKD had fired 20 times for approach. And now all it takes is two burns.” “Quiet!” blurted out someone at an adjacent monitor, where Igla special- ists were sitting. While turning around, the spacecraft turned its “nose,” i.e., its docking assembly, toward the station. During the turn, at 2028 hours, the telemetry 509
Rockets and People: The Moon Race struck the nerves of everyone sitting in hushed silence at the monitors: “The first block of DUSes is shut down! Backup activated…. Backup block of DUSes is shut down! Chayka digital circuit shut down. Igla shut down!” “Look what comes from nostalgia for Yevpatoriya,” I sighed, stunned by what had happened. Twenty-five degrees were left until the turn was completed. The space- craft’s angular motion continued due to inertia. Flight management at TsUP was in shock for several seconds. But it was as if the crew had just expected this. Without any hesitation, Dzhanibekov switched on the backup analog manual control loop. Just 25 seconds passed after the “accident,” which was displayed simultaneously on board the spacecraft and on the monitors in the TsUP control rooms. Dzhanibekov saw the DOS on the screen of his optical sight and calmly halted the spinning of the spacecraft. According to the radio coverage conditions, right at that time KIK lost communication with the vehicle for 10 minutes. At the most tense moment a special messenger ran in: “They’re asking for Yeliseyev to report to the State Commission!” Yeliseyev gave Legostayev, Branets, and me a questioning look. “Igla was operating normally according to all parameters all the way up until it shut down,” Suslennikov managed to say. I made the following recommendation: “In 3 minutes the vehicle will appear in the coverage zone. We’ll go downstairs to the communications room and make a joint decision there. It’s not right to summon a commander from the field of battle in a critical situation. Pass that on to the chairman of the State Commission.” 51 At 2036 hours, the spacecraft entered the coverage zone. It was just 100 meters away from the station. The crew very calmly reported that everything was fine and requested permission to perform manual docking. Permission was immediately granted. Docking proceeded without a hitch. During the following orbit the crew entered the DOS. There was thunderous applause from the guests in the balcony. Flashbulbs popped as the latest triumph of Soviet cosmonautics and the traditional friendship with the people of France was recorded for history. Our top brass didn’t have time to realize what had actually happened. The French guests smiled happily. While the large throng of brass and distinguished guests congratulated one another and those who had absolutely nothing to do with it, the true experts and culprits huddled around the consoles, not sharing the general jubilation, 51. The chairman of the State Commission was Kerim Kerimov. 510
People in the Control Loop trying to grasp what had happened. Vadim Kravets, who was in charge of the analysis group in Yevpatoriya, congratulated me for the brilliant docking and pointed to Mikhail Chertok, who had retreated into himself. “I thought that I had done a good job learning the signs that are quick tip-offs to off-nominal situations in the behavior of Chayka. If Mikhail Chertok is silently scratching his beard it means that he understood everything. There were no failures. This is the latest mathematical discrepancy in the program.” Evidently, Branets also knew that pensive scratching of the beard is a sign of enlightenment. Mikhail began to explain to him in a deliberate manner and drew something on his notepad. “Despite the happy ending, the State Commission demands my explana- tions,” said Yeliseyev, who had joined us. “What shall I report?” “Report that there were no failures in the system,” advised Branets. “There was a glitch in terms of tolerances for runtime check. The crew was well trained; it executed manual approach perfectly. We’re looking into the details on our test stand, and we’ll report in the morning.” There was no need for prolonged investigations of the “French off-nominal situation.” After conducting an investigation according to the service hierarchy, Branets reported, “The program algorithm for the runtime check had values for angular rates for each of the three axes loaded into it. Rendezvous required two correction burns. In so doing, the vehicle is turned at angles that are optimal for propellant consumption. After issuing the command to fire the attitude- control engines for a turn, the computer monitors the vehicle’s angular rotation rate relative to its center of mass. The angular rate depends on the operating time of the attitude-control engines and the moments of inertia relative to the corresponding axis. The computer knows the engine’s operating time, and the ratio of the angular rate to the inertial moment is loaded into the algorithm.” In this case, the angular rates during the turns exceeded the tolerance. The computer interpreted this as a failure of the angular rate sensors and switched from the first set to the second. But the second set also showed rates that did not correspond to the design values. Then, according to the runtime check algorithm, the digital (i.e., computerized) control loop was shut down. This happened at a range of 800 meters. Soyuz-T vehicles have a backup analog manual control loop. At the ini- tiative of Dzhanibekov and our manual control specialists, the crew had pre- liminary training for approach using this loop at a range up to 1,500 meters. Therefore, as soon as the computerized loop “failed,” Dzhanibekov switched on the backup, took over control—and docking took place at the calculated time. As far as root causes were concerned, the computer was not to blame. The culprit was a telephone connection between the planners and our dynamics 511
Rockets and People: The Moon Race specialists. The actual moments of inertia of this specific spacecraft differ from those that our dynamics specialists used to calculate the angular rate values. Instead of having official, accounted-for documents, they received the infor- mation over the telephone. After our circle of control specialists had pored over how much the values of the actual center-of-mass characteristics had deviated from the design values loaded into the runtime check program and received assurances that now everything would be corrected, I then had to brief the general designer on the causes of the incident. To my astonishment, instead of reacting to the incident with the anticipated and completely understandable outrage, Glushko dealt with it very calmly but was meticulously interested in the mathematical operations that the on-board digital computer received in order to predict the angular rates that depended on the duration of the attitude-control engines’ burn. A calm conversation resulted in the following instructions: announce orders that stringently stipulate the requirement to issue, before each launch, an archived calculation, in which the center-of-mass coordinates and moments of inertia will correspond to the actual vehicles and crews, rather than to designs from three years before. “It was quite difficult for us to establish a weight discipline,” Glushko said, “and we even strictly monitor the cosmonauts’ weight. But I didn’t think that you had tasked the computer to monitor the moments of inertia. All the plan- ners must understand what parameters are involved in the field of computer monitoring and bear responsibility for their authenticity.” The Soyuz-T crew proved that it was possible to perform docking using manual control from a range of around 1,000 meters. However, subsequently, the initial conditions did not always favor such a happy ending. Soyuz T-8, car- rying cosmonauts Vladimir Titov, Gennadiy Strekalov, and Aleksandr Serebrov, lifted off on 20 April 1983. After insertion, the traditional all-systems test was performed, including the Igla rendezvous radio system. During this process, it was determined that Igla’s main gyrostabilized pencil-beam antenna was unable to assume the necessary position. All of the experts agreed that the antenna control mechanism had jammed. To avoid aborting the docking, TsUP formed a team that worked through the night and came up with an automatic rendez- vous control procedure based on prediction without using Igla until the range was no more than 1 kilometer and then switching over to manual mode. After the completion of the automatic rendezvous using the scenario the team had developed, the range was 3 kilometers. Exercising discipline, the crew waited 30 minutes for instructions from TsUP. Finally, TsUP made its decision and granted permission for manual approach. Fifteen minutes later, the spacecraft approached to a range of around 200 meters from the station. Precisely at that moment, the vehicle and station entered 512
People in the Control Loop Earth’s shadow. In the darkness the crew managed to avoid collision, “diving” under the station. After emerging from the shadow, the Soyuz T-8 once again was 3 kilometers from the station. Calculations showed that the remaining propellant reserves were insufficient for new attempts at approach. After being briefed, the State Commission made two decisions: to have Soyuz T-8 return to Earth and to form the latest accident investigation commission to determine the causes for the failure of the Igla. Once again I found myself in the thankless role of chairman. Our commission succeeded in reproducing the mechanical jamming of
We supposed that a wayward nut or something of that ilk floating freely in weightlessness under the housing of the drive mechanisms had gotten into the works. In this connection we recalled Mnatsakanyan’s sensational declaration at the collegium of ministers: “Flying with Igla is tantamount to death!” But we didn’t have Kurs yet, and we had to fly. Until we had Kurs, our commission recommended to the ballistics and approach dynamics specialists that, “just in case,” they develop an approach procedure in the event of a complete radio system failure, so that it wouldn’t be necessary to improvise at the last minute. The recommendation was accepted for implementation. The team of Legostayev, Branets, Degtyarenko, Borisenko, Bragazin, and Semyachkin, unique in terms of its concentration of intellectuals, acquired an inventor’s certificate for a rendezvous method to be used in the event of the failure of the radio system that measures relative motion parameters. Special algorithms were introduced into the software of the on-board digital computer. In combination with the crew’s actions, this made it possible to substantially increase the probability of rendezvous with the station in the event of the failure of the on-board radar. “It bodes ill that you came up with this,” someone at the next meeting of our accident investigation commission said to the inventors. “Now in addition to failures of Igla or Kurs, we’ll have to figure out why your procedure failed.” A year and a half later the new technology came in handy to save the Salyut-7 orbital station. The story of the “clinical death” and resuscitation of Salyut-7 serves as a classic example, it would seem, of a small human error in the control loop and, subsequently, the truly heroic actions of people involved in another large control loop to eliminate the catastrophic consequences of this error. On 2 October 1984, a crew made up of Leonid Kizim, Vladimir Solovyev, and Oleg Atkov departed the station. 52 Temporarily, the Salyut-7 station 52. This was the Soyuz T-10 crew. 513
Rockets and People: The Moon Race remained in unpiloted mode and peacefully drifted in near-Earth space. The calm mode, which generated no interest in the press, the lack of a crew that might “do” something and require constant attention on the ground—all of this dulled the sense of vigilance of the personnel involved in the large control loop at TsUP. This sort of tranquility in space is deceptive. On 11 February 1985, at the end of the watch of the latest shift at TsUP, telemetry reported that current protection in the on-board complex control system had been tripped, shutting down the first, primary radio transmitter of the long-range radio communication system. It was an unpleasant incident, but far from an emergency. Unit S-190, stuffed with long-range radio com- munication system (DRS) equipment, housed two identical transmitters. It also contained receivers and decoders receiving commands from Earth. Once the radio system automatics had perceived the failure of the primary transmitter, it switched on the second—the backup. The shift that was on duty at TsUP was not surprised after discovering the automatic switch to the backup transmitter. It was well known that the set of radio instruments had exhausted its service life and had the moral right to one failure that would not lead to the failure of the whole system. A cargo transport vehicle had previously delivered the spare set that was on board. The crew of the upcoming expedition was supposed to replace the spent S-190 set with the new one. 53 The shift recorded the unremarkable incident (compared with the scales of other space incidents) in the flight log with the recommendation to call in a specialist on the on-board complex control system (SUBK) from TsKBEM and the DRS specialist from the Scientific-Research Institute of Space Instrumentation Building (NIIKP) in Moscow so that they could analyze the situation together and prepare a report. 54 But meanwhile they decided to work using the second transmitter. Flight control was conducted from TsUP in four shifts. Each one was on duty for 24 hours. I wasn’t able to determine what information the members of that shift, who were hurrying off to get some rest after a sleepless night, passed on to their relief shift members. And that’s really just a detail. All we know is that the director of the new shift did not summon or did not wait until the arrival of the specialists, i.e., the SUBK developers responsible for current 53. The original slated next crew for Salyut-7, the fourth primary expedition, included V. A. Vasyutin, V. P. Savinykh, and A. A. Volkov. Their backups were A. S. Viktorenko, A. P. Aleksandrov, and Ye. V. Saley. 54. SUBK—Sistema upravleniya bortovogo kompleksa; NIIKP—Nauchno-issledovatelskiy
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People in the Control Loop protection and the radio complex developers capable of making a diagnosis and giving a report about the shutdown of the primary transmitter. Subsequent examination determined that in keeping with tradition and the existing procedure, it was the duty of the shift flight director to wait for the specialists (developers of the DRS and SUBK) to show up. After analyzing the telemetry information, having debated with one another, they were supposed to make recommendations as to how to work thereafter, having signed off on the corresponding conclusion in the logbook. Evidently, the shift director decided “we didn’t just fall off the turnip truck.” Without waiting for those responsible for the systems, he gave the command to switch on the first DRS transmitter. And really, why not give the first set one more try? Perhaps an accidental actuation of the automatic protection had occurred. And if there really is a malfunction there, that’s what the current protection is for—it will trip again. You can reason like that at home if you’ve blown a fuse. Even a housewife who has seen smoke coming from the televi- sion or vacuum cleaner will not count on the reliability of the fuses and risk switching it on again. At TsUP they didn’t see whether smoke had appeared on board the DOS. But the actuation of the current protection in itself meant that the strength of the current exceeded the norm by three to five times. The findings regarding this incident, approved by Oleg Shishkin (deputy minister [at MOM] at that time) and signed by me, Ryazanskiy, Vorshev, and two military representatives, said:
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on 02 November 1985 during orbit 16,252, was contained by the current protection of the SUBK system and did not result in a failure in the operation of any of the systems. Up until 1320 hours, 51 seconds, all on-board systems were operating normally according to data from the analysis of telemetry information. 55. These indices denote the following spacecraft: 11F615A8 (Soyuz ferry vehicle, 7K-T), 11F615A12 (Soyuz vehicle for the Apollo-Soyuz Test Project, 7K-TM), 11F615A15 (original Progress cargo vehicle, 7K-TG), and 17K (DOS-class stations). 515
Rockets and People: The Moon Race 5. Commands from the ground to reactivate the first transmitter, which came after the actuation of its current protection during orbit 16,252, resulted in the development of a failure process. During orbit 16,254, attempts to switch on the clearly malfunctioning transmitter using a command from the ground resulted in a snow- balling short-circuiting process, as a result of which the integrity of the power circuitry of both transmitters was irreversibly damaged and the operation of the decoders was shut down. The failure of the decoders, which were installed in the same framework as the transmitters, deprived the station of the ability to receive any commands from Earth. The station went out of control. We were unable to reproduce the “snowballing process” under laboratory conditions with a short-circuiting current of 120 amperes passing through the transmitter because of the ambigu- ity and randomness of the phenomena. The findings contained the following modest statement: “The failures were confined to the S-190 framework of the DRS system and in the power circuits of the transmitters of instrument BKP of the SUBK system.” The short-circuiting current in excess of 100 amperes rapidly discharged the buffer batteries. The voltage of the on-board network fell to the minimum level, at which point the automatic circuit breakers were tripped, shutting down the electric power consumers one after another. After commands were issued from the ground to reactivate the malfunc- tioning transmitter, the strength of the current in the power circuit exceeded 100 amperes. Most likely the contacts of the radio transmitter power switch “burned out,” the insulation melted, and possibly there was short-circuiting somewhere else “along the way” in the cable network. There was a weak glimmer of hope that despite the loss of orientation, the station, while turning, would still receive enough energy from the Sun to sup- port the thermal mode to the minimum extent necessary. However, this same “snowballing process” also resulted in the malfunctioning of the sequencer, which at least once per day issued a command to connect the solar arrays to the buffer battery charging circuit. The command to charge the batteries did not get through from the ground or from the on-board sequencer. The system orienting the solar arrays on the Sun ceased to operate. The single power supply system—the on-board electric power station—completely broke down. All the electrical systems, including the thermal mode control assemblies, ceased to function. The station began to freeze. According to the calculations of the thermal mode specialists, the temperature inside the station would fall to –20°C [–4°F] in a week. The station became a big, useless, artificial satellite, which only the missile defense system’s space monitoring facilities could track. Salyut-7 fell 516
People in the Control Loop into a state of anabiosis. No ingenious sets of commands sent on board from TsUP were capable of bringing it out of this state. The station could only be saved by a human being, who after entering the station would disconnect the failed S-190 casing; replace it with a spare, which fortunately was on board the station; replace the cables damaged by the current surge with others brought from Earth; connect a warm storage battery that was also brought along; begin warming up the system; and restore orientation, thermal control, and everything else, including the life- support system. This repair team would have a lot of work to do. And it was unusual work. But how would a human being get there if the station was silent and the Igla rendezvous radio system, among others, also remained without power? This was the full-scale manifestation of Pilyugin’s law: “Emergency situations are the strongest impetus for new ideas and the improvement of systems.” This was one more of my versions of this law. Against the background of the Americans’ success, the loss of the Salyut-7 orbital station could become one more power- ful blow against the Soviet Union’s prestige in space. 56 Moreover, there were many costly instruments and materials for science programs on the station. “Save the station no matter what” was the overriding mission that the teams of control specialists set for themselves. Throughout February [1985] we assessed the degree of possible damage incurred in the station’s electrical network and developed measures to reani- mate the systems, which inevitably go out of order when exposed to prolonged freezing. Everything that was needed for the repairs and restoration was immediately put to work. The most important thing was still the question, who would fly to the station to revive it and how would they get there? After brief discussions they settled on the plan that Vladimir Dzhanibekov and Viktor Savinykh should be in the primary crew. Dzhanibekov already had experience in manual approach from great distances and was quite familiar with the station. 57 Engineer Savinykh from NPO Energiya was officially considered a specialist in optical sensors and manual orientation systems 56. Chertok is probably referring to the many successes of the early Space Shuttle program from 1981 to 1985. 57. Vladimir Aleksandrovich Dzhanibekov (1942–) had, by 1985, flown four orbital space missions, more than any other Soviet cosmonaut. These included Soyuz-27 (1978), Soyuz-39 (1981), Soyuz T-6 (1982), and Soyuz T-12 (1984). All of these missions had involved docking with Salyut space stations. 517
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