Recovering from Soyuz-1 tragedy
The actual preparation for the dual mission of Soyuz vehicles No. 5 and No. 6 began within weeks of the tragic death of Vladimir Komarov. It went without saying that the next pair of Soyuz ships had to be reverted back to automated mode to perform a dual test mission, which, hopefully, would be enough to rehabilitate the problem-plagued spacecraft and qualify it for another piloted mission after the accident.
Parachute containers and their hatches were the focus of the re-design in the wake of the Soyuz-1 tragedy.
Learning lessons from Soyuz-1
Racing multiple projects on parallel tracks, Vasily Mishin, Head of the TsKBEM design bureau, turned his attention back to the Earth-orbiting Soyuz 7K-OK spacecraft immediately after the last attempt to launch the L1 circumlunar spacecraft in September of 1967.
Vehicle No. 5, which was grounded at the last minute right after the launch of the troubled Soyuz-1 mission, had to be returned from the Tyuratam launch site back to TsKBEM's plant in Podlipki for refurbishment and conversion into an automated ship. In the meantime, the follow-on Vehicle No. 6 was still in assembly at the time of the Soyuz-1 accident.
On April 28, 1967, Mishin apparently chaired a meeting of TsKBEM's management, which among other things considered accelerating work on Vehicles No. 6, No. 7 and No. 8. As of May 7, Mishin apparently planned to complete the assembly of Vehicles No. 5 and No. 6 in June, so they could be ready for launch the following August. At the end of the same month, on May 31, Mishin still planned shipping vehicles No. 5 and No. 6 to the launch site between June 20 and June 26, 1967.
One of the hurdles facing the engineers was the 45K star tracker, which had misbehaved badly during the previous mission and needed urgent upgrades. During a meeting with his associates on May 25, Mishin noted a proposal from his deputy Boris Chertok to upgrade the 45K tracker with a special blind which would prevent the sunlight from reaching its sensors. The communication system employed during the parachute descent also had to be upgraded in the wake of the Soyuz-1 accident. Also, Mishin's associate Eduard Korzhenevsky reported that all the new blueprints, including those for the parachute container, which was being redesigned after the Soyuz-1 catastrophe, would be ready by June 1. A prototype of the new container had already been built, but some changes would still be required. (774)
During the Chief Designers Council convened on May 29, 1967, to review the "lessons learned" from the Soyuz-1 accident, where Korzhenevsky and Chertok proposed necessary upgrades to the future 7K-OK vehicles. Feodor Tkachev, who was in charge of the parachute system, a.k.a. OSP, reported that during five drop tests from the aircraft, the parachutes had opened as planned, despite internal pressure inside the descent module hovering between 0.46 and 0.64 atmospheres. (At the time, investigators speculated that high pressure inside the module could have squeezed the depressurized parachute container, thus preventing normal parachute release during the Soyuz-1 landing.) At the same time, Tkachev reported that during pressurization of the descent module, the parachute container had deformed by approximately 14 millimeters, seemingly supporting the "squeezing" hypothesis! The aircraft drop tests did not test the OSP system under most extreme descent angles and side velocities, Tkachev said. Finally, during the actual flight tests, the OSP had never been adequately tested, because of depressurization of Vehicle No. 3. Mishin's deputy Konstantin Bushuev agreed that the existing method for testing the landing system testing was inadequate. (774)
On June 1, Chertok presented Mishin with a list of hardware aboard the 7K-OK which would have to be upgraded to meet the recommendations of the State Commission.
As of June 20, Korzhenevsky told Mishin that the new design for the landing system and updated documentation for the installation of the modified parachute system for the 7K-OK and 7K-L1 spacecraft would be ready in five days. At the same time, Mishin's notes still mentioned plans for an earlier separation of the main heatshield on the descent module during future landings and the enlargement of the parachute container. These notes indicate that the re-design in the aftermath of the Soyuz-1 accident was still ongoing.
On July 5, Mishin mentioned Vehicle No. 6 undergoing assembly, with the instrument module just completed, despite one issue still open and the descent module scheduled to be ready on July 7. At the same time, Vehicle No. 5 was expected to arrive to the Control and Checkout Station, KIS, for final testing in four days. Mishin noted that the troublesome 45K star tracker for the spacecraft was still missing but was promised by July 8.
In preparation for a meeting with Dmitry Ustinov on August 17, Mishin penciled the launches of the two ships for the period between Oct. 15 and Oct. 20, 1967. It appears from Mishin's notes that the shipment of Vehicle No. 6 to the launch site in Tyuratam was now planned for August 20, with Vehicle No. 5 following on September 10. Key milestones for upcoming missions of the 7K-OK project looked as follows:
From Mishin's diaries, it is clear that when he arrived at Tyuratam for the preceding campaign of the 7K-L1 No. 4L spacecraft on Sept. 14, 1967, Vehicle 7K-OK No. 6 was undergoing integration of the descent module and the instrument compartment. Vehicle No. 5 was also at the launch site and the processing personnel was working with its habitation module.
On Sept. 25, still in Tyuratam, Mishin noted that at Site 31, Vehicle No. 6 had to be disassembled because of the need to upgrade its parachute container. Two days later, another management meeting dedicated to Vehicles No. 5 and No. 6, discussed various processing issues, including lack of personnel at Division 408, responsible for installation of thermal protection layers on the spacecraft, and a lack of regular transportation between Site 31 and the main residential area of the test range at Site 10.
Abandoning the rendezvous?
The flight scenario for Vehicles No. 5 and No. 6 was very similar to what had been originally devised for the first pair of the 7K-OK spacecraft in 1966. The highlight of the mission would be a rendezvous and docking in space, so crucial for the upcoming lunar exploration effort.
Ironically, due to lack of experience with planning rendezvous missions, the ballistic team neglected to ensure that the critical maneuvering of the two spacecraft would take place within the range of the Soviet ground station network. Instead, the two ships would have to complete the historic docking without any influence from the ground, making it a truly robotic process. Although the ships carried no cosmonauts, engineers gave them the "call" signs Amur and Baikal, after a river and a lake in the Soviet Far East. (466)
As of May 1967, Armen Mnatsakanyan, who led the development of the rendezvous system, planned that the two ships would dock with a relative speed of 0.2 meters per second.
During the October 16, 1967, meeting, the State Commission overseeing the flight set the launch dates for the pair of spacecraft for Oct. 25 and Oct. 27, 1967. According to Boris Chertok, during the meeting, Vasily Mishin, without consulting anybody, suddenly announced that the main goal of the dual flight would be the testing of all upgraded systems, including the new parachutes and of the rendezvous maneuvers, but that the actual automated docking would not be a part of the mission! Instead, the physical docking would be left to the follow-on pair of spacecraft with cosmonauts onboard, Mishin declared to the delight of Marshall Rudenko, General Kamanin and the cosmonauts. (The Air Force brass long insisted on manual maneuvering of the spacecraft, likely feeling, not without reason, that robotic systems could make the cosmonaut profession redundant. During the recess between the commission's meetings, Mnatsakanyan urged Chertok to fight this bizarre decision, but Chertok convinced him that it would not be wise and, possibly, not even necessary.
Chertok felt that if both ships performed well early in flight, he, as the technical head of the project, would have enough authority at mission control to convince others to go ahead with the "unplanned" docking. The ground control team would only need to prepare a special command sequence at two ground stations, which would power up the Igla rendezvous system on both spacecraft and then activate the rendezvous mode. If the docking failsed, the engineers could claim that they had no plans to do it, but if the ships did dock, who could blame the winners? Chertok shared his plan with General Pavel Agadzhanov, a top official at mission control, and his colleague Yakov Tregub, who both pledged full support and, in turn, relayed assignments to flight control and ballistic teams to prepare for live analysis of flight data and for the activation of the rendezvous mode.
Learning lessons from previous Soyuz missions, the planners streched the initial flight program to provide plenty of time for the no-hurry analysis of all systems on the active spacecraft before launching its target vehicle and committing to a rendezvous mission. The active spacecraft was now scheduled to fly solo for almost three days, before the mission control team at NIP-16 ground station in Yevpatoria on the Crimean Peninsula would give the State Commission in Tyuratam its advisory on the status of onboard systems. If the ship's orbit corrections would guarantee its pass over Tyuratam during Orbit 49, the second vehicle, code-named Baikal, would be launched into the same orbital plane.
Just minutes after the Baikal would enter orbit at the end of the third day or the beginning of the fourth day of the mission for the first spacecraft, ground control would have to determine the actual orbital parameters of the fresh vehicle. Immediately thereafter, a group of top ground control officials, known as GOGU, would have to decide whether to initiate the rendezvous process or to conduct additional orbit corrections. Flight controllers would also have to constantly monitor the propellant consumption and the adequate charging of the power batteries on the spacecraft. (466)
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Armen Mnatsakanyan led the development of the Igla rendezvous system for the Soyuz spacecraft.
Boris Raushenbakh was the brain behind the autoamted rendezvous system. Credit: RKK Energia
Igor Shmygelevsky developed theorethical foundations of the the so-called parallel rendezvous, which was employed during the maneuvers of the Kosmos-186. Credit: (201)
Anatoly Shiryaev worked on the rendezvous methods for Soyuz spacecraft. Credit: (201)
Evgeny Bashkin from Department 312 at TsKBEM was responsible for troublesome attitude control system of the Soyuz spacecraft. Credit: RKK Energia
Eduard Korzhenevsky supervised the redesign of the 7K-OK spacecraft in the wake of the Soyuz-1 accident. Credit: RKK Energia
Viktor Legostaev oversaw the development of the flight control system for the Soyuz 7K-OK spacecraft.