Building the first Salyut

Conceived, developed and assembled in merely 16 months, Salyut-1 was the product of a three-shift, no-days-off working marathon and the epitome of improvisation. Many design decisions were made right “in the field” during the actual assembly of the station, with leading engineers keeping round-the-clock vigils at the Khrunichev production plant.

Previous chapter: Origin of the Salyut project


Soviet officials review a full-scale mockup of the DOS-7K space station, which was reportedly built in just 12 days.



In 1969, Soviet space engineers set about building a quick-fix DOS-7K space station. Given the upcoming launch of the American Skylab orbital laboratory, which was anticipated as early as the middle of 1972, they had got the work cut out for them.

Unlike NASA, which had the luxury of launching its first space station on a leftover Saturn-5 moon rocket with a liftoff mass of 2,950 tons and a payload to low Earth orbit approaching 90 tons, Soviet engineers had to rely on the much smaller UR-500K (Proton) rocket capable of delivering under 20 tons of cargo.

At the time, the USSR's own lunar leviathan — the N1 — was marred by launch disasters, but still remained in development, giving some hope for a much larger Soviet space station to follow the original DOS-7K laboratory. In July 1970, Head of TsKBEM design bureau Vasily Mishin mulled using a two-stage version of the N1 rocket, identified in his notes as N-II, and apparently aimed at delivering up to 150 tons of payload, for launching a space station with an autonomous flight control system and an associated transport vehicle. In the proposed N-II architecture, the payloads would replace the third stage (Block V) of the original N1. Seemingly competing with Vladimir Chelomei's TKS project, Mishin also considered equipping his transport ship with a reusable reentry capsule based on the Descent Module of the Soyuz spacecraft but featuring a new (internal) layout. Moreover, a high-precision landing system, intended to remedy the unpredictability of parachute descent, had already been conceived for the future transport. Even space stations with artificial gravity were mulled. Nevertheless, Mishin remained a critic of the decision to transfer the space station development to his organization and blamed it for the slowdown of the Soviet lunar exploration program and for further worsening of his relations with Chelomei. (774)

In the interim, the reliance on the UR-500K rocket meant that a much smaller and simpler space station could be built to outrun Skylab into orbit. Engineers at the TsKBEM design bureau also had a considerable lead time, thanks to the available hulls of Almaz space stations which had been manufactured at the Khrunichev plant in Moscow for the Almaz project. Still, most interior components for Salyut were yet to be delivered.

Additionally, TsKBEM designers made some significant changes in the original Almaz architecture. They replaced the return capsule, originally planned to be attached to the front of the pressurized section, with a small airlock carrying a passive docking mechanism. In the meantime, the original docking section at the tail of Almaz was replaced with a propulsion section, largely borrowed from the Soyuz spacecraft. Each of newly added components was fitted with a pair of solar panels also borrowed from Soyuz. And the job of delivering crews to the station was left to the latest revision of the Soyuz spacecraft designated 7K-T. Some of the hardware apparently came from the lunar program. (954)

In December 1969, Yuri Semenov, at the time the leading designer of the L1 circumlunar spacecraft, was asked to take charge of the nascent space station program. In this politically sensitive post, Semenov would be reporting directly to Mishin.

Konstantin Feoktistov, the leading brain behind Vostok and Soyuz, who by then had his own space flight experience, also joined the space station work, as a deputy chief of the project. A number of other Korolev’s former closest associates played key roles in the development of the first Soviet space station. (134)

From its side, Chelomei's branch in Fili appointed Vladimir Pallo to be the leading designer on the DOS-7K project. Perhaps not coincidently, Pallo's older brother, Arvid, worked at OKB-1 and was an old associate of the late Sergei Korolev going back to rocket experiments in the 1930s.

Construction begins


Just before TsKBEM engineers went to celebrate the coming of the new year and the new decade on Dec. 31, 1969, a hastily assembled engineering team submitted the basic outlines of the newly proposed 17K space station and the DOS-7K complex with the Soyuz spacecraft. By the end of Winter 1970, the detailed project of the DOS-7K complex was ready with its formal defense conducted at the meeting of the Chief Designer Council on February 27.

All the attention then shifted to the Khrunichev plant in Fili, which suddenly became the new center for the Soviet human space flight effort. Built with German help at the turn of the 20th century, the Khrunichev production center was at various points a workplace for many legendary figures in Soviet aviation, including Andrei Tupolev, Vladimir Myasishev and Mikhail Mil. However during Khrushchev’s switch of priorities to rockets, the plant was full converted to the production of ballistic missiles developed at Vladimir Chelomei’s design bureau. Still, Khrunichev’s team retained many proud traditions of Soviet aviation, including its high engineering standards and attention-to-detail culture.

But the start of the DOS-7K project, brought a kind of cultural shock to Khrunichev with the “invasion” of Korolev’s boorish rocketeers from TsKBEM who were often looked down upon by proud aviators. For example, at the conclusion of the design work on DOS in March 1970, the Head of the Fili branch Viktor Bugaisky ordered the building of a full-scale mockup of the newly conceived station, which was a natural step for an aviation engineer. However, for rocket specialists from Podlipki, it was apparently a major surprise, at least, according to the recollections of their counterparts at Khrunichev. Mishin's notes appear to agree that it was a new step in the development process. The mockup was apparently built in just a few weeks and was prominently featured in a rare historic footage documenting the DOS-7K project. On March 20, Mishin personally saw the full-size replica of the future station at Khrunichev when he came to the factory to discuss the program's schedule with Minister Afanasiev. (774)

Of course, bad feelings still lingered at the top. The same month, Yuri Semenov paid a visit to Chelomei’s main headquarters in Reutov on the eastern edge of Moscow for a difficult talk. After listening to a bitter complaint from Chelomei about “intercepting his space station project” and with some mediation from Afanasiev, Semenov got the blessing from Chelomei to use four hulls of unfinished Almaz stations for the needs of the DOS-7K project. This hardware was crucial for the quick-and-dirty construction of test prototypes and the actual flight model of what would become Salyut-1. As was customary at the time, a pair of flight-worthy stations was to be built nearly in parallel, with two more to follow.

On March 26, Mishin also called Vladimir Barmin, the head of ground equipment development, to discuss the upgrades at Site 2 in Tyuratam for the upcoming processing of the DOS stations.

Before the flight model of the station could be certified for launch, one of its test versions was tried at the Institute of Medical and Biological Problems of Space flight, IMBP, by vacuum and extreme temperatures to ensure the capabilities of its life-support and thermal-conditioning systems. Another prototype was dedicated to radio-system tests and yet another to propulsion tests and, finally, a wooden mockup was used for fit checks of various internal components.

According to the technical summary presented by Chertok at the outset of the DOS-7K project in early 1970, TsKBEM had to provide 237 pieces of new hardware for 133 different systems, including 29 newly developed instruments. By May 23, 1970, Mishin already identified the production of the internal components as the most critical part of the project. By July 19, Mishin estimated a lag of between 1.5 and 2 months in the production of equipment for DOS-7K at TsKBEM.

By the end of August 1970, work at Khrunichev also started falling behind the super-ambitious schedule, but still, the project quickly approached the assembly stage. On August 31, Mishin noted in his diary an apparent deadline for the launch of Salyut ahead of a Communist Party Congress expected in Spring 1971.

As of September 1970, officials were still targeting the launch of the station as early as January 1971. Interestingly, in October 1970, Mishin noted that a total of 60 million rubles were to be spent on the DOS project by January 1, 1971, compared to 400 million rubles expended on the Almaz project.

On November 17, 1970, Mishin visited the Khrunichev plant to see the first DOS station in final assembly. (774)

After several delays, the flight version of the station was finally completed at Khrunichev plant at the end of 1970 and immediately shipped to TsKBEM in Podlipki for integrated testing. At the time, the launch of the first station and its first crew was planned for March 1971, however, the station was delivered to the launch site in Tyuratam in March 1971, still in need of final processing. Here, in a record-breaking 40 days, engineers worked in three shifts conducting the final checks of the complex spacecraft, targeting the launch by April 20.

For the lack of a proper test stand, the team “tried” the reliability of the station’s stabilization system by manually rocking the almost 19-ton vehicle in its huge mechanical cradle!


Chronology of known activities in the DOS-7K project in 1970:

1970 Jan. 15, 10:00: Chief Designers Council meeting on the DOS-7K project chaired by Konstantin Bushuev and Boris Chertok.

1970 Jan. 16, 8:30: Mishin meets with Yuri Semenov at TsKBEM to discuss the DOS-7K project.

1970 Jan. 28, 15:00: TsKBEM management meeting on the organization of the DOS-7K project.

1970 Feb. 2, 19:30: Minister Afanasiev visits TsKBEM for a review of the DOS-7K project.

1970 Feb. 27, 10:00: Formal defense of the DOS-7K project at the Chief Designer Council.

1970 March 10: Minister Afanasiev chairs a meeting on the DOS-7K project.

1970 March 20, 15:00: A meeting on the DOS-7K project at Khrunichev plant.

1970 April 9, 16:00: A commission on the full-scale mockup of the DOS station meets.

1970 April 16, 12:00: Mishin chairs a TsKBEM meeting reviewing issues of the DO-7K project raised at the previous meeting with Afanasiev and Bugaisky.

1970 April 17, 14:00: Sergei Afanasiev chairs a meeting on the DOS-7K project at Viktor Bugaisky office in Fili. Mishin in attendance.

1970 April 30, 12:00: TsKBEM management reviews candidates for the first two crews of the DOS-7K complex.

1970 May 15, 16:00: Minister Afanasiev chairs a meeting on the DOS-7K project in Fili, with Mishin in attendance.

1970 May 25, 10:00: The TsKBEM management reviews DOS-7K project. including the development of the DOS No. 3 and No. 4 vehicles, as well as DOS-7KS upgrade.

1970 June 25, 13:00: The Collegium of the Ministry of General Machine-building, MOM, reviews the DOS-7K project.

1970 July 24, 16:00: Dmitry Ustinov chairs a meeting on the DOS-7K project with Mishin, Bushuev, Feoktistov and Vachnadze (Director at TsKBEM experimental plant, ZEM) in attendance.

1970 Aug. 31, 11:00: Mishin and the leadership of TsKBEM visit Khrunichev plant for a review of DOS assembly and management of the schedule delays.

1970 Sept. 4, 08:30: Ustinov chairs a meeting on the DOS-7K in Fili.

1970 Sept. 4, 17:00: Ustinov chairs a meeting on the DOS-7K at TsKBEM in Podlipki.

1970 Sept. 9, 18:00: Georgy Tyulin chairs a meeting on the DOS-7K assembly and testing schedule at Khrunichev plant.

1970 Sept. 12, 12:00: Dmitry Ustinov visits TsKBEM for the review of DOS-7K, N1-L3, RT-2 and RT-2P projects.

1970 Oct. 21: Minister Afanasiev chairs a meeting on the DOS project.

1970 Nov. 17: Mishin visits Khrunichev to see the first DOS station in final assembly.


The article by Anatoly Zak; Last update: July 7, 2022

Page editor: Alain Chabot; Last edit: April 19, 2021

All rights reserved


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Engineers work inside full-scale mockup of the DOS-7K.



The first-generation Salyut during the assembly.


The first generation Salyut.


DOS-7K llikely imaged during thermal tests at NIIKhimmash facillity in Zagorsk.





Fairing test separation on the prototype of the DOS-7K station.



DOS-7K during final processing in Tyuratam.