Long duration orbital station of the third generation Salyut-7
The next station of the third generation was Long Duration Orbital Station LDOS No. 52 (Salyut7). The station in many respects repeated station LDOS No. 5. Nevertheless a number of technical modifications was implemented on it. In particular, the capability of mounting additional solar arrays in flight was envisaged that essentially increased the power supply capacity of the station. To increase efficiency of the target use of the station special research module 37KE with a complex of science hardware for astrophysical research and Earth observation was developed. It was equipped with a set of X-ray telescopes, an ultraviolet telescope, sight OD5, other systems to carry out the science and application research program and experiments, the up-to-date control system based on the Salyut-5B computer and gyrodynes to provide the reactive mode (without fuel consumption) of the station attitude control. However, further because of the delays during its manufacture the decision was accepted to reorient it to the next generation station Mir. Upon entering the Mir station in April 1987 this module was called Kvant.
On April 19, 1982 the Salyut-7 long duration orbital station was injected into orbit. From April 19, 1982 to June 25, 1986 four prime crews and five visiting crews worked on the station. The first expedition – cosmonauts A.N. Berezovoi and V.V. Lebedev who were launched by the Soyuz T-5 vehicle – worked in orbit for 211 days, namely from May 13 to December 10, 1982. During this expedition the following experiment was performed: mini-satellites were launched from the airlock of the station. On May 17 and October 17, 1982 two radio amateur satellites Iskra separated from the station.
The Salyut-7 Orbital Station with the Soyuz T-5 vehicle docked
The second expedition – cosmonauts V.A. Lyakhov and A.P. Aleksandrov who were launched by the Soyuz T-9 vehicle – worked on the Salyut-7 LDOS for about 150 days, from June 27 to November 23, 1983, having performed, in particular, such a unique operation as mounting of additional solar arrays and supporting activities with TLV (Kosmos1443), being part of the complex.
The Salyut-7 Orbital Station with the Soyuz T-6 docked vehicle, reequipped in flight with additional solar arrays
The third expedition – cosmonauts L.D. Kizim, V.A. Soloviev and O.Yu. At’kov who were launched by the Soyuz T-10 MTV – worked from February 8 to October 2, 1984. The cosmonauts stayed in orbit almost 237 days!
During this expedition one of the most serious repair and refurbishment work was performed in space. One of the fuel pipelines on the station lost the pressure integrity perhaps because of its breakdown by meteorite. During six EVAs the cosmonauts managed to isolate the failed pipeline and connect a new one to the propulsion system. For connection of an additional pipeline the filling couplers were used. This work was preceded by the ground test and the crew training for many months. A special press for tight cross-clamping of the pipeline and special valves which were set on the filling couplers were developed. All this was done for the first time in world practice.
During the expedition (on July 17–29, 1984) when the visiting crew consisting of V.A. Dzhanibekov, S.E. Savitskaya, I.P. Volk worked, the woman extravehicular activity was performed for the first time in the world. S.E. Savitskaya conducted a number of experiments on the external surface of the Salyut-7 LDOS; they were on cutting, welding and soldering of metal plates, as well as spraying of protective coatings on them in space using a new universal manual tool developed at the Paton Institute of electric welding in Kiev.
On February 11, 1985 the station communication was lost in the unmanned flight phase because of the failure of the command control systems and the MCC operator error, as a result of which the recharging mode of the buffer batteries was violated because of the impossibility of the ground interference with the automatic equipment operation, the system was de-energized and the station completely failed. There was a serious situation. The complete loss of the station became real. Specialists of NPO Energia began to study the following issue; if it is possible to dock with completely uncontrollable station. To solve this problem it was necessary to know the angular rate of the station rotation. This required the following: to involve the ground facilities of different departments/agencies including the antimissile defence aids.
To provide docking to “non-cooperated object” the thorough test of the forthcoming operations and intensive training of the future crew were carried out. Such an operation had no analogs in the history of manned cosmonautics. Experts estimated probability of successful docking as 0.7–0.8. And despite this fact the decision on providing the docking was made: it was necessary to keep the station.
That is why unprecedented work on the station recovery began. On June 6, 1985 a special expedition – cosmonauts V.A. Dzhanibekov and V.P. Savinykh was launched into space by the Soyuz T-13 vehicle. The vehicle with the help of the target designations from Earth and manual control using a laser range finder and ODC approached to the station, docked with it as with “non-cooperated object”. The cosmonauts carried out the repair and refurbishment work and the Salyut-7 LDOS was put back into operation. In the course of this work there were rather dramatic moments. For example, thermal control system (TCS) among other systems did not operate on the station. Water onboard was frozen. The cosmonauts could take only a limited amount of water onboard the station. And until the last moment it was not known if they have enough time to heat the station to take advantage of the available water supplies or they would have to return to Earth with no work performed because of water lack.
After completing operation of the fourth prime crew (cosmonauts V.V. Vasyutin, V.P. Savinykh, A.A. Volkov, a premateur landing on November 21, 1985 because of the crew commander illness) and in connection with the beginning of the Mir station operation on February 20, 1986, work with the Salyut-7 station was terminated from June 25, 1986.It is true that before the event a unique (for the first time in the world) flight of the prime crew-1 of the Mir OS (L.D. Kizim and V.A. Soloviev) to the Salyut-7 long duration orbital station and back was performed. The crew transported a part of the research hardware of 800 kg mass from the Salyut-7 station to the Mir station.
To study the behavior of the MSC structure and equipment during long duration operation it was decided to transfer the Salyut-7 station to high-altitude orbit with a long life (as it was predicted, at least 10 years). But the prediction proved to be inaccurate because of unexpectedly high density of the atmosphere in years of the active Sun, the station began to descend more rapidly than it was proposed. The world public was concerned about the probability of the station fragments falling on densely-populated areas of the planet. Although specialists knew how small this probability was, there was enough anxiety. . On February 7, 1991 the Salyut-7 station together with TLV (Kosmos1686) docked to it ceased to exist in dense layers of the atmosphere over the South America in the Chile area.
General Designer of NPO Energia V.P. Glushko played an important role in organizing the planned increase of the cosmonaut flight duration. He aspired to constant and continuous operation of stations in the manned mode, insisted that the crews consisted not only of men but of women too. And the flights on the Salyut stations and then on Mir are an illustration of such a systematic increase in the duration of orbital flights. Each decision on the subsequent increase in the flight duration was made on the basis of thorough analysis of the previous flight materials by physicians with the development of additional recommendations and procedures accompanied by the creation of the additional medical equipment.
The way passed by cosmonautics in this direction impresses! After a 18-day flight on the Soyuz-9 MTV in June 1970 (then it was a record of duration) cosmonauts A.G. Nikolaev and V.I. Sevastyanov were in a rather grave physical condition within a week.
Based on the results of the Soyuz-9 MTV flight a compete set of preventive medical equipment (a treadmill, a veloergometer, Penguin loading suits, Chibis vacuum facility to exert negative pressure in the lower part of the body and other equipment) was developed with which all orbital stations were outfitted. The developed measures proved to be efficient: though later the crew flight duration later regularly increased, the cosmonauts upon return to ground felt normally. The record flight of crew surgeon Valery Polyakov on the Mir OS is a striking example: he stayed in space about 438 days without noticeable consequences for health.
Experience of long-term man-in-space flights is one of the most important achievements of national cosmonautics. State Scientific Center of the Russian Federation – Institute of BioMedical Problems of the Russian Academy of Sciences played an important role in the increase of the flight duration onboard the orbital stations.
The program of the joint research with the participation of astronauts of foreign countries began on the Salyut-6 station and it was continued at the subsequent MSC. In the beginning the program envisaged flights only together with the Soviet crews of cosmonauts – representatives of the countries of the socialist community (ChSSR, GDR, Poland, Bulgaria, Hungary, Cuba, Vietnam, Mongolia), then the cooperation sphere was enlarged and cosmonauts of India, France, Afghanistan, Syria, Japan, Great Britain, Austria, Slovakia visited the Salyut-7 and Mir orbital stations. In spite of the fact that these flights in many respects were used for political ends, the experience gained when organizing the international cooperation in the joint projects was, of course, important for implementation of the subsequent programs.