THE FIRST GENERATION SPACE STATIONS—SALYUT 1-5

FIRST GENERATION DESIGN

The first generation of Soviet space stations spanned the years 1971 through 1976 and encompassed the successful launch of three stations, while two others were failures. The design of the station changed somewhat during this period, both externally in terms of the placement of the solar panels, and internally to allow for different experiments. Each had a single docking port.

As each space station in this series was launched, more details became available about its design. In the case of space station dimensions, the information seemed contradictory since apparently in some cases external attachments such as radio antennas were included in the dimensions and in other cases they were not. It is assumed here that the basic station dimensions, including those of Soyuz ferry craft (which is 7.5 meters long) docked at one end, did not change and were: length—21 meters (23 meters if antennas are included); maximum diameter—4,15 meters; interior volume—100 cubic meters; weight—25 metric tons. Without Soyuz, the stations weighed 18.6 to 18.9 metric tons, and were 13.5 meters long. The most significant change to Salyut externally was the change from four solar panels on Salyut 1, to three larger, individually rotatable solar panels on Salyut 3 and 4. Figure 27 shows these different configurations in comparison with the second-generation space station Salyut 6.

MILITARY VERSUS CIVIL STATION DISTINCTION

During this time, Western experts generally thought that the Soviets had two space station programs: one optimized for civilian space experiments, the other for military.

The distinction was drawn when Salyut 3 was launched in 1974. This station was placed in a lower orbit then Salyut 1, the crews sent to the station were all military, rather than mixed civil/military as had been the case on Salyut 1, and when the crew entered the station, they switched to military telemetry. When the next space station, Salyut 4, was launched it was placed in a Salyut 1-type orbit and the crew was again mixed military/civil, and remained on the civilian telemetry channels. Salyut 5 paralleled the Salyut 3 mission profile. In addition, both Salyut 3 and 5 ejected capsules after the departure of the crew which were recovered, as is the practice with military reconnaissance satellites. With hind-sight, the conclusion was reached that had they been successful, Salyut 2 would have been the first military space station and Kosmos 557 would have been civilian, thus giving an alternating civil-military-civil-military pattern to launches.

The Soviets never admitted to such a dual program, insisting that all were for continuing the scientific exploration of space. Western observers, however, count Salyut 1, Kosmos 557, and Salyut 4 as civilian space stations, and Salyut 2, 3, and 5 as military stations performing a reconnaissance function.

SALYUT 1 DESIGN

On April 19, 1971, the Soviets launched the world's first space station, Salyut 1 (see figure 29). The station initially was described by the Soviets as 20 meters long with a maximum diameter of 4 meters, and weighing 25 metric tons with Soyuz attached.

The station had several compartments, which were subsequently designated the assembly, transfer and work areas. The transfer tunnel from the ferry craft to the station was 3 meters long and 2 meters in diameter. The main habitable portion of the station, or work compartment, was divided into three sections: A small cylinder 3.8 meters long and 2.9 meters in diameter; a large cylinder 4.1 meters long and 4.15 meters in diameter; and a cone connecting the two which was 1.2 meters long. The unpressurized assembly module completed the station and was 2.17 meters long and 2.2 meters in diameter.

Pictures of Salyut 1 showed eight chairs, seven at work stations, and 20 portholes, some unobstructed by instruments to give a good view of the Earth and outer space.

Externally, Salyut 1 had two double sets of stationary solar panels, placed at opposite ends, extending like wings from the smaller diameter compartments. Heat regulation system radiators, orientation and control devices, and some scientific instruments were also mounted externally.

SALYUT 3 DESIGN

After the Salyut 2 and Kosmos 557 failures discussed below, the Soviets finally succeeded in launching Salyut 3 on June 25, 1974. Salyut 3 is generally considered to have been the first operational military space station. The Soviets announced that Salyut 3 was 21 meters long with the same 100 cubic meter interior volume as Salyut 1. Changes to the station included miniaturized circuitry in the control loops; more efficient power and life support systems, including better thermal control; solar panels which were capable of rotating 180 degrees (unlike the stationary ones on Salyut 1) so the station itself did not have to constantly face the Sun, with three larger panels instead of the four on Salyut 1; and a general redesign of the interior. In addition, the docking port was located at the aft end of the station. (24)

The 4-meter diameter working compartment was described as being subdivided into control, working, and living sections, with a corridor to the left side of the ship, from front to back, connecting the various sections to each other. The floors and ceilings were painted different colors (dark for the floors, light for the ceiling) to make the cosmonauts feel more at home, and the floor was covered with a Velcro-type material to assist with walking.

The living quarters, in the front portion just forward of the control compartment, had four windows; a special sofa for medical experiments; one fixed position and one swinging bed (coming oui from the bulkhead to conserve space); hot and cold water sources; stable for eating; storage space for clothes, linen, and entertainment gear (which included a tape recorder for music, a chess set, and small library); and a shower and toilet.

SALYUT 4 DESIGN

Launched on December 26, 1974, Salyut 4 was announced as being 23 meters in length, with the same volume and weight as the other Salyuts. It is considered by Western experts as a civil space station (see figure 30).

Further information on the solar panels was released: They were individually rotatable, with a total area of 60 square meters producing 4 kilowatts of power. The panels turned automatically on signals from solar gauges indicating what position the Sun was in at any moment. A third bank of solar batteries was also added.

The Soviets also announced that the station had a micrometeorite monitoring system (MMMS) with 4 square meters of panels serving as sensors. Further details of the thermal control system were also described. The Salyut walls were made of "screen-vacuum" heat insulation which precluded heat exchange between the station and space, and were made of many layers of synthetic film sprayed with aluminum. To heat the station, an intricate system of radiators was used which both collected solar heat and radiated surplus thermal energy. Three or more backup systems were available.

The interior of the station was described in much greater detail. The unpressurized assembly area was said to contain the fuel tanks and orbital and orientation engines. The transfer area contained two of the seven work stations (for navigation and scientific observations) plus the "Raketa" vacuum cleaner and a long sleeve of rubberized fabric which extended into the ferry craft to provide fresh air. The work compartment was described as consisting of two cylinders connected by a conical bridge. The smaller one was 2.9 meters in diameter and 3.8 meters long with the solar panels attached to the outside. The large cylinder was 4.15 meters in diameter and 4.1 meters long with a cone-like structure containing scientific instruments and equipment (for example, a telescope). To the left and right of the cone were refrigerators for storage. The conical bridge was 1.2 meters long. Walls were painted in soft greens, yellows, and blues.

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

The main control panel (housing navigation instruments, clocks, radio communications monitors and controls, the Globus navigational indicator, and two keyboard command signalling devices) faced the transfer tunnel. To the left of the main panel were the life support controls with regeneration cylinders for purifying the air on both sides of the panel. On the right was a scientific work station, and a medical research work station was located in the conical bridge section.

Behind the main command post, in the center, was the eating table, with direct feeds for hot and cold water. To the left, looking from the transfer tunnel, and behind the panels was a small cupboard for plates and other utensils. Beyond the table on the side panels were grids covering the cooling-drying assembly, with fans to circulate the air.

Farther back was the medical area with a swivel chair for vestibular studies, and a closet for medical instruments. At the right was the exercise equipment and above that, a shelf for the tape recorder. At the end of the cylinder was the sanitary-hygiene area, which was separated from the rest of the room and had forced ventilation. There was no shower on this station.

SALYUT 5 DESIGN

Launched on June 22, 1976, Salyut 5 is considered a military Salyut and of similar design to Salyut 3, i.e., the docking port was at the rear. The Soviets released a few more details about the space station. For example, on this station, the entire instrument compartment was covered with blue fabric with a soft interlayer to protect the sharp corners of the instruments. According to the Soviets, this change was made on the recommendation of the crews that had occupied previous stations.

Otherwise, the station was essentially the same as previous stations, although the cosmonauts did test a new attitude control device. The Soviets also announced that there was an onboard computer to direct the operation of instruments without human interaction.

References:

A. SOVIET SPACE PROGRAMS: 1976-80, (WITH SUPPLEMENTARY DATA THROUGH 1983) MANNED SPACE PROGRAMS AND SPACE LIFE SCIENCES PREPARED AT THE REQUEST OF HON. BOB PACKWOOD, Chairman, COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION UNITED STATES SENATE, Part 2, OCTOBER 1984, Printed for the use of the Committee on Commerce, Science, and Transportation, U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON, D. C., 1984

22. Soldat und Technik, No. 8, Aug. 1981, op. cit.

23. Aviation Week and Space Technology, Oct. 13, 1980, p. 13. In 1982, the Soyuz T-6 crew had an especially hard, and early, docking, because the computer failed, and on Soyuz T-8 in 1983, the mission had to be aborted because of a failure in rendezvousing with Salyut 7, due to the failure of the antenna mast to deploy.

24. Soviet Launches of More Military Salyuts Expected. Aviation Week and Space Technology Dec. 4, 1978, p. 17. See also: Clark, Phillip S. The Design of Salyut Orbital Stations. Spaceflight, v. 23, Oct. 1981, p 257-8.