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DOS Salyut-4


By Marcia S. Smith*

1971-1975/ 1976-1980


Soyuz 17 and 18 with Salyut 4

Still in orbit at the time of this writing, Salyut 4 has already hosted two manned missions which totaled 93 days: Soyuz 17 for 30 days, and Soyuz 18 for 63. In turn these missions broke the Soviet space endurance record and brought them closer the American record of 84 days on Skylab 4. Salyut 4 also has accommodated one unmanned mission, Soyuz 20.

Salyut 4 Station Design Details

.—Salyut 4 was launched on December 26, 1974 into a 270 x 219 km orbit, inclined at 51.6°. This was soon raised to a 350 km circular orbit, higher than previous Salyut's, and done apparently to conserve fuel. There were again modifications to the space station, for example easier access was provided to certain mechanical areas of the ship for repair and replacement of parts.

The length of the space station was announced as 23 meters with the same volume (100 cubic meters) and weight (over 25 metric tons).

The solar panels were described as individually rotatable and having a total area of 60 square meters producing 4 kilowatts of power. The panels turn automatically on signals from solar gauges indicating what position the Sun is occupying at any given moment. There also was a third bank of solar batteries added.

The space station has an MMMS, micrometeorite monitoring system, with 4 square meters of panels serving as sensors. At first particles were measured acoustically, but now a capacitator type is used which registers both the impact and penetrating power of each particle. Two thin metal plates, which are insulated by a layer of teflon, close together when struck by a particle and a pulse is sent to the control center. The skin of the station (which reflects 3/4 of the light rays hitting it) serves as a shield from these particles. If a meteorite hits the ship with a velocity greater than 4 km per second, the particle explodes on contact and a second layer of skin picks up the debris.

The Russians also described their thermal control system. The walls of Salyut are made of "screen-vacuum" heat insulation which precludes heat exchange between the station and space, and are made of many layers of synthetic film sprayed with aluminum (they claim a piece of dry ice placed between layers of this material would not melt for hours even in direct sunlight). To heat the station, an intricate system of radiators is used which both collects solar heat and throws off surplus thermal energy. Three or more backup systems are available.

Salyut's interior was again described, broken down into three separate areas: assembly, transfer and work. The assembly area is un pressurized and contains the fuel tanks and orbital and orientation engines. The transfer area is the cylindrical part of the ship, two meters in diameter and three meters long, where two of the seven work posts are located at windows for navigation and scientific observations. The "Raketa" vacuum cleaner is kept here also. In this area there is a long sleeve of rubberized fabric which extends into the ferry craft to feed it fresh air. The walls in this part of the ship, as well as in the work area, are painted in soft greens, yellows and blues.

The work compartment is the main part of the space station and consists of two cylinders connected by a conical bridge. The smaller cylinder is 2.9 meters in diameter and 3.8 meters long with the solar panels attached to the outside. The large cylinder is 4.15 meters in diameter and 4.1 meters long and has a cone which broadens downward where scientific instruments and equipment are kept at a work station. To the left and right of the cone are refrigerators for storage. The conical bridge is 1.2 meters long.

The Russians gave the following description of Salyut 4 from front (near the transfer tunnel) to back.

The main control panel, housing navigational instruments, clocks, radio communication monitors and controls, the Globus navigational indicator to show what part of the Earth is being passed over, and two keyboard command signaling devices, faces the transfer tunnel and has two work stations. To the left of the main panel are life support controls with regeneration cylinders for purifying the air on both sides of the panels. At the right of this is another work station for control of scientific instruments. Another work station for medical research is located in the conical bridge section.

Behind the main command post, in the center, is a table for eating. To the left, looking from the transfer tunnel, and behind the panels, is a small cupboard for plates, knives, forks, etc. There are two heaters with tubes for soup and coffee. These are heated to 70° C and then the device turns itself off automatically. Hot and cold water are fed directly to the table.

Beyond the table on the side panels are grids covering the cooling-drying assembly which sucks in air, cools it, and feeds it back. Fans are provided for circulation of the air.

Farther back is the medical area where a swivel chair is located for experiments on vestibular reaction, as well as a closet for medical instruments. At the right is exercise equipment, and above them on the right is a tape recorder for music. At the end of this cylinder is the sanitary-hygiene area which is separate from the rest of the rooms and has forced ventilation. .

The Soviet press release did not mention the largest piece of equipment on board Salyut 4, the space telescope. From other sources its location in the center of the large cylinder is known.

Although both Soyuz 17 and 18 docked with Salyut in the usual manner, with manual control being engaged at 100 meters, the Russians announced that manual control could be activated as early as 200-300 meters from the station (although this might not always be wise since deviations in the course could occur) or the entire operation could be carried out automatically. They suggested the latter method was not always feasible due to an area of “silence” where a crew can respond more quickly than an automatic sensing device.

Soyuz 17 Salyut-4

The launch of Soyuz 17 came at 2153 GMT on January 10, 1975 . Its crew, Lt. Col. Aleksey Gubarev and Flight Engineer Georgiy Grechko, were boosted into an initial low orbit which by the fifth revolution was raised to 354 x 293 km, inclined at 51.6° with a 90.7 minute period. At this point, Salyut was in a 350 km circular orbit so two maneuvers were required to put Soyuz into a docking Position. The actual docking occurred at 0125 GMT January 12 in the usual manner.

The significantly higher orbit of this mission suggested that its tasks were astrophysical in nature, and indeed the Russians announced the following projects for the space crew: research into the physical processes and phenomena in outer space, Earth resources photography, Medico-biological research, and testing of the station's systems and communications were supported by the Molniya satellite and three tracking ships in the Atlantic: the Akademik Sergey Korolev near Sable Island off Canada's east coast, and the Ristna and Nevel in the southern Atlantic.

During the 30 day mission, the cosmonauts followed a cycle of six days of work and one of rest. They typically ate four small meals daily with one-half hour of exercise before breakfast one hour between breakfast and lunch, and one hour between lunch and dinner. No shower was provided, so the cosmonauts washed themselves with moist gauze napkins moistened with lotion. Shaving was accomplished either with a safety razor or an electric one which sucked the whiskers into a container. During the flight, Gubarev lost 2.5 kg of body weight while Grechko lost 4.5 kg. Physicians explained the flight engineers greater loss as a result of extra work performed at the expense of sleep.

At 0608 GMT on February 9, Soyuz 17 undocked from Salyut and at 1103 GMT landed 100 km northeast of Tselinograd. The landing apparently took place in a blinding-snow storm, with wind velocities up to 20 meters per second, a visibility of 500 meters, and a ceiling of 250 meters. Despite the adverse weather, rescue teams were on the scene immediately, and within ten minutes the cosmonauts were on board the helicopter.

Salyut-4 Soyuz-17 Experiments

The announced aggregate weight of the scientific apparatus on this mission was 2.5 tons, and was used for the following experiments:

Medical —A, veloergometer (apparently part of the Polinom-2M apparatus) was used to measure and predict the functioning of the cardiovascular system, tone of the blood vessels, venous circulation, and circulation of blood to the brain. They also checked the effects of decompression on the lower part of the body with a special (Chibbis) decompression suit that was worn not only during exercises, but also for hours at a time while the cosmonauts performed routine daily tasks. Samples of blood and exhaled air were taken for analysis on Earth, as well as microbes from various parts of the ship. The Russians also checked vestibular reaction by use of a swivel chair, and used a "Plotnust" device for ultrasonic measuring of changes in the composition of bone tissue. There also was an electric muscle stimulator, Tonus, which could send pulses to any specific set of muscles to exercise them.

Exercise equipment included the treadmill used on other flights (which was reportedly 90 cm long and 40 cm wide), and a. new addition, a bicycle. Tills was described as a comfortable chair with pedals, turned alternately by the feet and hands, connected to a generator which stored the electricity that was produced. They followed a regime of three days of regulated exercises, and then one day where they could choose whatever they liked.

Other Biological .—Experiments continued with microorganisms and higher plants, as well as with certain biological species. An experiment called "Oazis" involved growing leguminous plants, specifically peas, which sprouted in three weeks. The relationship between this "Oazis" and the Oazis-1 and -2 on earlier flights is unclear. Fruit flies (Drosophila) and the embryos of frogs that developed in space were observed to check their biological development in a weightless environment.

Earth Resources .—Not a major experiment in Soyuz 17, the crew only performed a small amount of Earth photography covering the following areas: the Kurile Islands , the Caspian depression, Central Asia , the southern European portion of the Soviet Union , the Far East and Kazakhstan .

Atmospheric .—The "Emissiya" system was used to study the red line of atomic oxygen in the atmosphere at a height of 250-270 km. Spectrographs in the rear part of the space station scanned the Earth's horizon in areas where the electron system was active. These studies will be valuable both for meteorology and for determining flight dynamics for satellites. Related to those studies, the crew continued research into the characteristics of plasma flow just outside their space station to see how it affected the rate of orbital decay.

Earth Radiation .—The Earth's radiation was studied with an infrared telescope/spectrometer (ITS-K). The telescope has a 300 mm diameter mirror, and the slit of the spectrometer is precisely in the telescope's focus. Here the radiation entering the device hits a fluorite prism. The apparatus receives wavelengths from 1-2 to 7 microns and has a 10 x 20 minute field of view, and the spectrometer has a resolving power of 600 lines per millimeter.

Although the Earth's surface, the Moon and the galactic planes were all studied by the infrared device, its main target was the Earth's atmosphere. Spectra of solar radiation which had passed through the atmosphere were recorded at sunrise and sunset. To do this, the slits of the spectrometer were placed parallel to the Earth's horizon. The information is needed for determining the temperature of the atmosphere as well as distribution of water vapor and rare gases such as ozone. The atmosphere can only be explored to about 35 km with aircraft, and although sounding rockets can travel higher, they leave vapor trails which do not permit close examination of some aspects of the atmosphere's characteristics.

In order for the readings to be accurate, the apparatus must be kept extremely cold. Until this mission, a conventional cold generator with compressors was used. But a great deal of energy was required for this method, so this time the Russians provided an ice coat of solid nitrogen which maintained the proper temperature quite successfully.

Astrophysical. —Two X-ray telescopes were used to study radiation from various areas of the universe. A "Filin" set of spectrometers was mounted on the outside of the station to detect the radiation by sensors, and was linked in parallel with a set of two optical telescopes (70 cm long with a 6 cm diameter and 1 degree field of view) to identify exactly what object was emitting the radiation. They used two modes of observation: one with the axis of the telescope permanently fixed on one area of the sky, and the other where the ship's commander oriented the ship and the flight engineer positioned the telescopes, as had been done with Orion-2. The Russians announced that for the first time an autonomous system of stellar orientation was used to train the telescope, but provided no further details. The second X-ray telescope RT-4, was not described until the Soyuz 18 mission.

During their extensive operation of this system, the crew studied the Crab Nebula, supernova explosion remnants in both the Vela and Puppis constellation, the Ori (sic) star (probably Rigel), white dwarfs, neutron stars and black holes, as well as the background radiation of the galaxy along its meridian.

Solar Photography .—A. telescope made in Crimea was used for studies of the dynamics of the Sun in the ultraviolet. The orbital solar telescope (OST) was equipped with a KDS (for Krymskiy Difraktsionnyy Spektrometer—Crimean Diffraction Spectrometer) and it studied specific areas of the Sun, not the entire disc at one time. Although the Russians announced that the telescope had operated for two weeks before the crew came aboard, they also reported that the pointing system had malfunctioned causing the Sun to blind the main mirror. (The apparatus had two mirrors, the main one 25 cm in diameter with a 2.5 meter focal length, and a rotating mirror.) To correct this and make the telescope operational for the remainder of the flight, experts at the Crimean Astrophysical Observatory decided to reposition the rotating mirror so that the Sun's rays would be reflected into the main mirror. To accomplish this, the cosmonauts had to position the ship so that the telescope's axis was pointing directly at the center of the Sun. This was no easy task, for the crew had to measure the time it took for the rotating mirror to move from one support to another in its normal mode of operation, so they could calculate where it had to be stopped to assist the main mirror. The only way to do this was by listening to the mirror's movements, which the crew did with a stethoscope from their medical kit. Not only did this make the device operational, but once again proved man's usefulness in space.

Although the main mirror was in a conical niche to protect it from micrometeorites, the cosmonauts had to resurface it by spraying a new reflective layer onto it. The Russians were delighted that the process worked well, for it was a deciding factor in their astrophysical plans for future space stations. If the surface could not be recoated, there would be no use in sending up other telescopes for long duration exploration.

The Sun was quiet during the Soyuz 17 mission, but good photographs were taken of dim flocculi (light patches on the Sun barely discernible from Earth) which exhibited bright features. These areas were simultaneously photographed on Earth for comparison purposes.

Navigation. —Two navigation systems for autonomous control of the station were mentioned, and their relationship to each other is vague. Reports stated that daily tests were made of the Kaskad (Cascade) autonomous navigation system, consisting of an onboard computer that makes navigation measurements and determines orbital parameters. The Russians hope it will reduce fuel consumption for orienting the ship. The "Delta" system was described in much the same way, although it seems as though this system was a functioning part of Salyut, not an experimental version like Kaskad.

Communications. —A new method of communication was experimented with that utilized a teletype system called "Stroka." This time the crew only tested the system, so it was used primarily for personal communications from family and friends, press reports on the mission, and basic information on orbital parameters. The system apparently works the same way newspaper teletypes do, with the message coming out on a strip of paper. This has the advantages that a permanent record is provided of communications from Earth, and it relieves the crew of the need to be present when the message arrives. They can read it whenever they have time.

Soyuz "April 5th Anomaly" Aborted Mission

On April 5,1975 at about 1103 GMT, the Russians launched a spacecraft with the announced purpose of docking with Salyut 4 and continuing scientific experiments. But a third stage separation malfunction of the A-2 booster forced the mission to be aborted and the crew, Col. Vasiliy Lazarev and Oleg Makarov, found themselves landing in cold, snowy Siberia southwest of the town of Gorno-Altaisk , 1,600 kilometers away from the launch site and only 320 kilometers north of the Chinese border. After the failure, the mission was renamed the "April 5th Anomaly" and the Soyuz 18 designation it would have received was given to the next craft in the series.

TASS did not announce the shot until two days later, presumably to give the crew time to be rescued and their health assessed. It is suspected that they spent the night at the landing site before recovery teams could meet them. They reportedly exited the spacecraft shortly after landing and built a fire.

The primary significance of this failure was its relationship to ASTP, to be launched only three months later. Konstantin Bushuyev, Soviet program director for ASTP, assured his American counterpart, Glynn Lunney that the launch vehicle used in this instance was an old version of the one to be used in July, and that none of the systems in common were suspect in the malfunction. This raised a lot of eyebrows in the West for several reasons. First, there had been no suspicion that the A-2 vehicle had two versions, although experts were aware of differences in the Soyuz craft itself. Second, since the Soyuz's docking target, Salyut 4, was in a substantially higher orbit than that to be used for ASTP, it seemed unlikely that a less capable launch vehicle would be used. Third, the A-2 is used for unmanned as well as manned missions. Why the Russians would use the older version on a manned flight rather than using them up on unmanned missions is unclear.

NASA did not appear overly concerned with the failure, however. The Russians were preparing two complete sets of hardware for ASTP, so if one failed another would be ready on the pad. Also, a failure before reaching orbit would not affect the safety of the American crew.

Senator Proxmire, chairman of the Senate subcommittee dealing with NASA's appropriations, did not concur however, and called for a CIA briefing on the capabilities and safety of the Russian space program. Comments on this classified briefing are given in the annex to this chapter.

Soyuz 18Salyut-4

Six weeks after the failure of the Soyuz flight, Soyuz 18 was launched to dock with Salyut 4. At 1458 GMT on May 24, 1975 , Col. Petr Klimuk and Flight Engineer Vitaliy Sevastyanov were boosted into orbit by an A-2 vehicle. By the second revolution their orbital parameters were 247 x 193 km, inclined at 51.6°, with a period of 88.6 minutes. After at least two maneuvers, a normal docking was achieved with Salyut 4 on May 25. The orbit after docking was 356 x 344 km, with a period of 91.3 minutes.

Although the Russians reported that the crew required a "normal" amount of time for adaptation to weightlessness, they noted that this period was ten days, somewhat longer than previous crews needed. In a new medical experiment, experts decided to adopt ten days as an adaptation period in reverse, that is, use the ten days before the end of the mission to begin preparing the cosmonauts for Earth conditions. Remarking that the Soyuz 17 crew found physical exercise inadequate, physicians placed Klimuk and Sevastyanov on a high salt diet and encouraged them to drink a lot of water to increase body fluids. Although both reported feelings of dizziness such as those they had experienced during initial adaptation, after landing on Earth doctors reported the experiment was successful. (13)

The mission carried 90 scientific and experimental installations to work in the following areas: studies of the Sun, planets and stars in various bands of the spectrum; investigation of geological-morphological objects on the Earth's surface; physical processes in the atmosphere and in cosmic space; medical-biological tests; and tests of the station's systems and design.

During the 63 day mission, the joint Apollo/Soyuz launches took place and two communication sessions ensued between the crews of Soyuz 18 and Soyuz 19. The issue of having two Russian manned missions in space at the same time was another topic for Senator Proxmire's CIA briefing.

The crew landed on July 26 at 1418 GMT, 56 km southwest of Arkalyk , Kazakhstan . Although they set a new space duration record for the Soviet Union , they did not surpass the American record of Skylab 4.

Since most of the experiments for Soyuz 18 were continuations of Soyuz 17 projects, there is no need to discuss them in detail here. The Polinom and Chibbis suit medical experiments were continued, onions and peas were grown in the Oazis system, and Drosophila development was studied. Research into the atmosphere was continued with "Emissiya," as was solar photography and other astrophysical observations, and the Stroka communication was utilized again.

Soyuz 18 Salyut-4 Other Experiments Included

Earth Resources .—A great deal of attention was given to Earth photography this time, supposedly so they can compare photographs of areas in winter with those taken in summer. Covered in this mission were: the European part of the Soviet Union, the Transcaucasus, northern Kazakhstan, republics of Soviet Central Asia, Primorye territory, Kurile Islands, Rostov and Volgograd oblasti, the Ukraine, Turkmenia, the Pamirs, Sakhalin Island, the eastern part of the Baykal-Amur railway, the Orenberg region, the Volga, maritime areas, mountains, sea currents, and shelves and deposits on beds of rivers at their mouths. All in all, over 8.5 million square kilometers were photographed.

Atmospheric. —Experiments that had been conducted on previous flights into the nature of the space immediately surrounding Salyut were continued and given the name "Spektr." They involved investigations of the physical properties of the cosmic environment, specifically interaction between space vehicles and space. An analyzer on board the station oriented in the direction of flights measures the density, composition and temperature of particles striking the hull of the ship to see how they affect orbital decay.

Astrophysical .—The two X-ray telescopes were used again, and a description of the RT-4 mirror 'X-ray device was given. This telescope was used to study soft X-radiation carrying photons with energy less than one kiloelectronvolt. It had a parabolic mirror with a diameter equal to 200 mm, a photon counter, a system of gas filling, and an electron device for primary processing of information. It looked at known sources of radiation rather than scanning for unknown sources as the Filin spectrometer had done, and had an independent orientation system accurate up to 15 seconds of arc. The crew studied the constellations of Scorpio, Virgo, Cygnus and Lyra, focussing especially on X-l Scorpio and X-l Cygni. The latter is suspected of being the ever-elusive black hole, although its correct classification now is a neutron star. Because of the atmosphere, exact readings on this object are not possible from Earth, and the Russians stated they could now measure its mass, size, luminosity, density and temperature.

Navigation and Tracking .—A new tracking technique was tried out using lasers. The laser pulses were sent from Earth and reflected back by an optical comer reflector installed in the ship. These trials were successful. . .

Concerning navigation, no real clues were given as to the distinction between "Delta" and "Kaskad." It is possible that Delta is the system presently being used, which has a radio altimeter and other instruments to compute orbital parameters, and Kaskad is an innovation for the future using only stars and other celestial objects for guidance.

Systems. —The crew practiced thermal regulation and life support in various modes. They also used a freon installation to study how liquids are affected in orbital flight. The results will be used for creating hydraulic systems for spacecraft.

Soyuz-20: Unmanned Test Flight With Salyut-4

After the end of the Soyuz 18 mission, Salyut 4 remained in orbit, prompting speculation that a third crew might be sent to work on the station. This would have been a new accomplishment, since the lifetimes of Salyut 1 and 3 had been too limited for this, and each had actually hosted only one crew.

On November 17, 1975, the Soviets did indeed launch another Soyuz to Salyut 4, but it was unmanned. During the Soyuz 15 mission, the Soviets had indicated that they were developing a tanker spacecraft to refuel space stations in orbit, so preliminary speculation centered around the possibility that Soyuz 20 was the first such mission. There were many doubts, however, since there was no indication that Salyut was equipped with a docking port on the service module end, an assumed necessity for fuel transfer (as confirmed with the Progress/Salyut 6 flights).

On a post-ASTP mission to Houston, Soviet ASTP technical director Konstantin Bushuyev announced that Soyuz 20 was definitely not a refueling mission, and said that it would conduct rendezvous and docking tests and check out modifications to the Soyuz for that purpose. A few days later, on December 4, the Soviets announced that Soyuz 20 was carrying out parallel biological studies with Kosmos 782, and that it carried turtles, drosophila, cacti, gladioli bulbs, vegetable seeds, corn, and legumes. Soyuz 20 and Kosmos 782 had different microclimates for the specimens aboard, so comparison studies could be made. Kosmos 782 and the biological aspects of the Soyuz 20 mission are further discussed in the next chapter.

On February 15, the Soviets tested the Soyuz propulsion system, and the ship undocked from Salyut 4 the next day after 90 days, 11 hours, and 48 minutes of flight. The Soviets announced that important results had been obtained for perfecting and testing the design and onboard systems of both spacecraft. The length of the flight suggested that Soyuz 20's main objective had been a test of the spacecraft in a powered down condition to determine whether the systems could be successfully reactivated after that period of time. Thus, speculation centered on the prospect for even longer Soviet manned space station missions.



13. "TASS, Moscow , July 29, 197S, 0600 GMT. In a subsequent report (TASS, September 18, 1975) the Russia ns make no reference to this report, and say that the cosmonauts needed only 4 days for adaptation.


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