NW033 1/144 Salyut 1

History Notes by Barry Davidoff


Thirty years before the International Space Station (ISS), the world’s first space station, Salyut 1, was launched in 1971 by the Soviet Union. Since the Soviets had been beaten in the race to the moon, they now concentrated their efforts on long duration orbital missions.

The basic structural components of Salyut were created by Chelomei’s design bureau as Almaz, which was a military observation platform. In Almaz, two cosmonauts would remain in orbit for about a month taking reconnaissance photos and obtaining electronic intelligence. Almaz’s goal was similar to the American Manned Orbiting Laboratory (MOL), which had been canceled in 1969 due to high cost and that unmanned reconnaissance satellites already were capable of achieving most of the objectives of MOL.

Due to the scheduled launch of Skylab in 1973 following the conclusion of the Apollo program, and that the Soviet Union desired to surpass the United States in at least one aspect of space flight, the Salyut program was commenced on an expedited basis. In February 1970, Dimitri Ustinov, Secretary of the Central Committee for Defense and Space, issued a directive. It ordered the Chelomei design bureau to combine its Almaz station with Korolev’s design bureau’s (now headed by Vasili Mishin) experience in building manned spacecraft to develop the Salyut space station.

Salyut’s design reflects the hasty addition of components taken from the Soyuz program which included:

The speed at which both design bureaus proceeded is demonstrated by the completed station being shipped to the Baikonour Cosmodrome only a year after Ustinov’s directive had been issued. Salyut 1 was launched by a three stage version of the Proton rocket on April 19, 1971 into a 180 kms. x 214 kms. orbit.

Salyut 1 Components

The design of Salyut 1 formed the basis for later Russian space stations. As shown by this New Ware model, cylinders of four different diameters formed the basic shape of Salyut. Seven work stations were positioned in the first three cylinders of Salyut.

The first section was the transfer compartment to which the Soyuz spacecraft docked. It was 2 meters in diameter and 3 meters long. The transfer compartment served as an airlock between Soyuz and the working areas of Salyut. There was a docking port for Soyuz at the far end, and a connecting hatch to the remainder of Salyut at the other. One set of solar panels used to power the station was attached to the transfer compartment, while the other set was attached on the propulsion system at the rear of Salyut. The transfer compartment also housed the Orion 1 telescope used for observing in the ultraviolet spectrum

The second cylinder was the small work compartment. It was 2.9 meters in diameter and 3.8 meters long. The main instrument panel used to control the station’s functions was at the front end of the cylinder, near the hatch to the transfer compartment. There was a small table upon which the cosmonauts ate, which was attached to a tank used to supply water.

The largest cylinder was the large work compartment and it was 4.15 meters in diameter and 4.1 meters long. The large work compartment housed many of the scientific and medical experiments as well as the treadmill. At the far end of the large work compartment was the sanitary and hygienic unit which could be partitioned off from the rest of Salyut. This unit had its own ventilators and water supply. The cosmonauts’ sleeping bags were located on the port and starboard sides, though they sometimes slept in the orbital section of the Soyuz. This cylinder also housed OST-1, which was a two meter solar telescope. Unfortunately, following the launch of Salyut 1, the telescope cover failed to jettison, thus preventing its use.

At the rear of Salyut was the propulsion system that was not accessible to the cosmonauts. This last section was a cylinder 2.2 meters in diameter and 2.17 meters long. The propulsion system was adapted from Soyuz and designated the KTDU-66 engine. It used a mixture of UDMH (unsymmetrical di-methyl hydrazine) and nitric acid. About 1500 kg. of propellants were stored, which was sufficient for a total burn time of 1000 seconds. The engine was recessed within the propulsion system. Two sets of vernier engines were located in the recessed area of the main engine and other vernier engines were mounted on the outside of the propulsion cylinder. The second set of solar panels was attached to the sides of this cylinder. Salyut carried 28 square meters of solar cells in all.

To provide the cosmonauts with a method of orienting themselves, the interior of Salyut was painted in different colors. The forward and rear walls were light gray. The walls in the two work compartments were light yellow on one side and apple green on the other. The floor was painted dark gray. Salyut 1 bears the name ”Zarya” (Dawn) on its sides, which was its original name. Its call signal was changed to Salyut prior to its launch.

Salyut 1 Work Stations

Seven different work stations were divided among the first three cylinders. Full advantage of zero gravity was taken so some of the work stations were mounted on the ceiling, floor and walls in different orientations. The seven work stations were designated as follows:

Station 1 (small work compartment)-controls and instrumentation for the station

Station 2 (small work compartment)- navigation and orientation.

Station 3 (large work compartment)- scientific experiments and a viewing port.

Station 4 (conical frustrum between the large and small work compartments)- medical experiments.

Station 5 (transfer compartment)- astronomy including the Orion 1 ultraviolet telescope and the Anna 3 gamma ray telescope.

Station 6 (small work compartment)- navigation and orientation.

Station 7 (small work compartment)- earth reconnaissance using a variety of cameras.

Soyuz 10 Flight

As Salyut 1 was being developed, the Soyuz spacecraft was being modified for its new mission as a ferry to orbiting space stations. Three cosmonauts without spacesuits could be carried aboard. Originally developed for going to the moon, significant modifications were made for the flights of Soyuz 10 and Soyuz 11. Since the Soyuz space craft would be attached to Salyut most of the time, the life support system was simplified and the amount of oxygen and supplies decreased. This version carried two solar panels as wings. The fuel capacity of Soyuz was reduced from 755 kg. to 500 kg. The toroidal compartment at the rear of the Soyuz propulsion module also was eliminated.

A new docking mechanism was designed for the Soyuz 10 flight that allowed for the internal transfer of the crew to Salyut. On Soyuz 4 and 5 in January 1969, the docking mechanisms could not be moved out of the way between the two Soyuz orbital modules so two cosmonauts had to do a space walk to transfer from one space craft to the other. In the new docking mechanism the docking probe and cone could be swung away so the Soyuz crew could enter the transfer compartment of Salyut 1 directly. These modifications would have fateful consequences during the next two missions.

On April 23, 1971 Soyuz 10 carrying three cosmonauts lifted off from the Baikonour to begin their stay aboard Salyut 1. The crew was commanded by Vladimir Shatalov and had Alexsi Yeliseyev as the flight engineer and Nikolai Rukavishnikov as the test engineer. Shatalov and Yeliseyev were making their third trips into space and Rukavishnikov was making his first flight. There already were significant problems aboard Salyut. The cover of the scientific compartment had failed to jettison so the OST –1 solar telescope and several other experiments could not function. Six of the eight ventilation systems had failed as well.

During rendezvous with Salyut the ionic orientation system aboard Soyuz failed due to contamination so much of the approach had to be performed manually. After almost a day in orbit, Soyuz 10 soft docked with the space station. The spacecraft, however, was unable to achieve a final hard docking with Salyut. After remaining linked together for four orbits, Soyuz 10 separated and began maneuvers to perform the first landing of a Soviet manned space craft at night. The crew made an emergency landing two days after being launched. Incredibly, the Soviets announcement made at the time stated that all mission objectives had been achieved and that the crew never intended to enter the space station.

The cause of the failure to hard dock was kept secret for many years. After the fall of the Soviet Union it was revealed that the shock-absorbing claws of the Soyuz 10 docking system had not been designed to be sufficiently strong. During docking the automatic Reaction Control System on Soyuz fired to make a significant change in the spacecraft’s attitude creating greater stress. As a result, the claw failed forcing a premature termination of the flight.

The Fateful Flight of Soyuz 11

Following the failure of Soyuz 10, the Soviets quickly planned a second attempt to occupy Salyut. Originally, the crew was to be commanded by Alexsei Leonov, who was the first man to walk in space as part of the Voskhod 2 mission in March 1965. Leonov would later be the Russian commander of the Apollo Soyuz Test Project mission in July 1975. The other two members were to be Valeri Kubasov and Pyotr Kolodin. Unfortunately, a week before the flight, doctors found a swelling in Kubasov’s right lung which they thought was tuberculosis.

At first, mission planners considered replacing only Kubasov with his respective back-up, Vladislav Volkov. Just four days before launch, it was decided to replace the entire crew rather than Kubasov alone. Therefore, at almost the last minute, the crew of Soyuz 11 was determined to be Georgi Dobrovolosky, (commander), Vladislav Volkov (test engineer) and Victor Patsayev (flight engineer). Volkov had flown previously aboard Soyuz 7, while the other two were making their first flight. The decision to change crews would be profound.

On June 6, 1971 the new crew of Soyuz 11 was launched into space. After rendezvous and docking a day later the crew began occupying the space station. The prior record for space flight was 18 days set by Soyuz 9 in June 1970. It was intended that the crew would have a much easier time in the more commodious Salyut in a mission lasting approximately 30 days. During the mission, the crew conducted more than 140 experiments. Although the OST-1 solar telescope could not be used since its cover failed to jettison, the crew used the Orion 1 ultraviolet telescope and the Anna 3 gamma ray telescope. The crew performed a vast array of medical experiments which were essential to measure the effects of long duration missions. In keeping with the original intent of its Almaz design, the cosmonauts were scheduled to observe the third launch of the giant N-1 rocket from Baikonour. Due to a postponement, the cosmonauts did not see the N-1’s spectacular explosion 50 seconds after its launch. Instead, the cosmonauts recorded the flights of two ballistic missiles.

During the mission there was some discord among the crew. Although Georgi Dobrovolosky was the commander, Vladislav Volkov clashed with him since Volkov thought his opinion should prevail because he had previously flown in space. During a small fire aboard Salyut 1 caused by a short circuit, Volkov acted hastily ignoring the assistance of the two others.

After 23 days in orbit and setting a new duration record, the crew entered Soyuz 11 to return to earth on the night of June 29. The return flight would be tragic.

Shortly after the crew undocked from Salyut, communications with the Soyuz 11 capsule were cut off as the capsule flew out of range of the tracking stations. Voice contact was never regained. The descent capsule landed near its target in Kazakhstan. When the recovery teams reached the capsule all three cosmonauts were dead from rapid decompression.

The State Commission investigating the accident determined the following sequence of events. Due to the re-design of Soyuz as a ferry, the crew did not wear space suits as a method of saving weight and room. In preparations for undocking, a warning indicator light appeared signaling that the hatch between the descent and orbital modules of the Soyuz had not closed properly. In attempting to solve this problem the descent module may have been over-pressurized. When the descent module separated from the orbital module as part of normal re-entry, the charges fired simultaneously, rather than sequentially, so that a ventilation valve in the descent module abruptly opened. This valve was intended to open only after landing to bring fresh air into the capsule. The crew may have first thought that the capsule’s atmosphere was leaking out through the hatch between the descent and orbital modules that had earlier caused the indicator light to turn on. The crew discovered too late that it was the ventilation valve and Dobrovolsky and Patsayev made an unsuccessful attempt to close it. As result of the valve opening in the vacuum of space, the capsule entirely depressurized in 112 seconds.

The crew of Dobrovolsky, Volkov and Patsayev, was regarded as heroes and the Soviet Union mourned. They were interred in the Kremlin Wall, during a state funeral presided over by Party Secretary Leonid Brezhnev and the Politburo. Thomas Stafford of Apollo 10 flew to Moscow especially for the funeral to represent NASA and the American astronauts.

Continued Difficulties

The loss of the Soyuz 11 crew was not the only major failure to plague the Soviet space program during the last week in June 1971. Three days prior to the loss of the Soyuz 11 crew, the third N-1 moon rocket was destroyed during its launch. The inability of Soyuz 10 to hard dock and the loss of the Soyuz 11 crew, combined with the N-1 failure, according to Asif Siddiqui in Challenge to Apollo marked for the Soviet space program, ”its nadir-an absolute low unthinkable a few years before.” It would be more than two years until the Soviets flew another manned space mission in September 1973 with the launch of Soyuz 12, which carried only two cosmonauts wearing spacesuits.

Before the Soviets would occupy a second space station, the entire Skylab program was successfully conducted. After three successive failures, the second Soviet space station, Salyut 3, was finally orbited on June 24, 1974. DOS 2 had failed to reach orbit, Salyut 2 was severely damaged when its engine misfired and Kosmos 557’s fuel was exhausted during its first orbits due to a faulty orientation sensor. Salyut 3, like Salyut 2, was intended for military purposes and was derived from Chelomei’s original Almaz design. The Soyuz 14 crew of Pavel Popovich and Yuri Artyukhin occupied Salyut 3 for 16 days performing reconnaissance as well as scientific experiments. It has been reported that one of the cameras used aboard Salyut 3 could resolve objects on the ground as small as 30 centimeters.

Legacy of Salyut 1

Although there was a stream of failures surrounding Salyut 1, the design of the space station itself was successful and formed the basis for many other space stations. Salyuts 4, 6 and 7 all used similar designs of two cylindrical work compartments, a transfer section and a propulsion section. The Salyut 1 design was used for the core and Kvant modules of Mir, which orbited the earth for 15 years from 1986-2001. The International Space Station continues the legacy with its Zveda habitation module. It was the second Russian ISS module to be launched and should continue in operation past the year 2020, fifty years following the flight of Salyut 1, the world’s first space station.