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Kosmos-496

DOS-7K No. 2

DOS-3 & 4

INSIDER CONTENT

DOS-7K No. 3

Soyuz 7K-T No. 36

Soyuz-12

Soyuz 7K-T No. 34A

Soyuz-13

Soyuz 7K-TM

Soyuz 7K-TM No. 71 (Kosmos-638)

INSIDER CONTENT

Soyuz 7K-T No. 61

INSIDER CONTENT

Almaz OPS-2

Soyuz-14

Soyuz 7K-S

7K-S No. 1L (Kosmos-670)

INSIDER CONTENT

Soyuz 7K-TM No. 72

INSIDER CONTENT

Soyuz-15

Soyuz-16

Salyut-4

Soyuz-17

Soyuz-18-1

Soyuz-18

Soyuz-19

The editor would like to thank Michael Lutomski and his staff at Johnson Space Center, Houston, for corrections.

The Salyut era: First space stations

During the 1970s, the USSR launched a series of progressively sophisticated orbital laboratories serving as habitats for increasingly lenghty crew visits. They were preparing the foundation for permanent presence of humans in the Earth's orbit.

Previous chapter: Soviet lunar program

Key figures in the Soviet space program attending launch in Tyuratam in the mid 1970s (left to right): cosmonauts Georgy Beregovoy and Vladimir Shatalov, Designer General of NPO Energia Valentin Glushko, Minister of General Machine-building Sergey Afanasiev, Director of NPO Energia's ZEM experimental plant Konstantin Vachnadze and General Kerim Kerimov, the Chairman of the State Commission. Photo-collage by Anatoly Zak

During the 1960s, multiple organizations within the Soviet rocket industry studied projects of space stations, primarily with military goals. The most advanced was the Almaz project at the TsKBM design bureau in Reutov, which entered the full-scale development phase, despite considerable technical and political challenges. In 1969, the rival TsKBEM bureau in Podlipki convinced the Kremlin to endorse its own "crash" development of a "civilian" space station based on Almaz. What would become the Salyut space station program aimed to run in parallel with the lunar exploration and to pave the way to the construction of large permanent settlements in the Earth's orbit.

The USSR begins enduring space station program

Faced with the loss of the Moon Race in 1969, Soviet space strategists conceived a detour of the national human space flight effort to a less expensive but what would turn out to be a lasting effort — the development of a long-term habitat in space.

Building the first Salyut

Conceived, designed 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 vigil at the Khrunichev production plant.

Design of the first Salyut space station

The Salyut space station, identified in the industrial documentation as 17K, structurally consisted of a transfer compartment with a diameter of 2.1 meters, followed by the main work section, in turn containing a science instrument compartment, and closed up with an instrument section.

The USSR orbits its first space station

On April 19, 1971, at 04:40 Moscow Time, a three-stage UR-500K (Proton) rocket lifted off from the "Right" pad at Site 81 in Tyuratam and a few minutes later successfully delivered into orbit the first 17K space station (No. 12101). Unknown to the world, the name Zarya (sunrise) had been painted on its body, however the official Soviet media announced it as Salyut-1.

The USSR launches first space station crew

Four days after the Salyut space station entered orbit, the first crew was also on its way. After one aborted launch attempt, the Soyuz-10 transport ship lifted off with three cosmonauts in early hours of April 23, 1971, and reached the station the following day, but then ran into a string of potentially dangerous problems just inches away from its destination.

Soyuz-11 begins a fateful expedition to Salyut

On June 6, 1971, three Soviet cosmonauts, assigned to the flight at the last minute, departed Earth aboard the Soyuz-11 spacecraft for a record-breaking month-long flight aboard the Salyut space station.

Soyuz-11 crew lost at landing

On June 30, 1971, the three members of the Soyuz-11 crew lost their lives just minutes from landing when their Descent Module suddenly depressurized on its way back to Earth from the Salyut orbital laboratory.

Kosmos-496: Fixing Soyuz-11 flaws

On June 26, 1972, the Soviet space program made its first major step on a difficult road to recovery from the Soyuz-11 disaster a year earlier. The upgraded version of the 7K-T vehicle orbited the Earth without crew in the autonomous flight under name Kosmos-496.

DOS-7K No. 2: A failed Salyut

On July 29, 1972, the USSR attempted to launch a second copy of the Salyut space station, however, its UR-500K (Proton) rocket failed to reach orbit, so the mission was never publicly announced.

Salyut space station gets first major upgrade (INSIDER CONTENT)

Based on the very mixed experience in launching and operating the first two Salyut space stations in 1971 and 1972, Soviet engineers at the TsKBEM design bureau built a second pair of orbital labs internally known as DOS-7K No. 3 and No. 4. Despite their designations, they differed significantly from their two predecessors.

DOS-7K No. 3: Skylab's challenger

On May 11, 1973, the USSR launched its fourth space station and the first major upgrade of the original Salyut design, just days ahead of the American Skylab. The 19-ton Soviet lab reached orbit as planned, but an immediate crisis put Soviet engineering and mission control teams to a severe test... Today, it is often only an asterisk in history books, but in 1973, the launch of DOS-3 produced a political earthquake across the Soviet space program and even got the KGB involved.

Kosmos-573: Re-confirming Soyuz fixes

On June 15, 1973, a heavily modified version of the Soyuz 7K-T spacecraft went into orbit without crew or much publicity on its second mission to ensure that all the lessons from the fatal Soyuz-11 accident in 1971 had been learned. In addition, the test flight sought to resolve problems encountered during the ill-fated launch of a Salyut space station a month earlier.

Soyuz-12: USSR resumes crew missions after deadly accident

In September 1973, the Soyuz-12 spacecraft carried two cosmonauts on a test mission of the new crew vehicle variant modified after the loss of three cosmonauts aboard Soyuz-11 more than two years earlier.

Kosmos-613: Soyuz flies a two-month endurance mission

From Nov. 30, 1973, until Jan. 28, 1974, a Soyuz spacecraft without crew secretly orbited the Earth, testing the limits of its onboard systems and setting a new record for its autonomous mission.

Soyuz-13 flies pioneering astronomy mission

In December 1973, two cosmonauts launched into space aboard a custom-built Soyuz-13 spacecraft, carrying the Orion-2 telescope for astrophysical observations. During the eight-day flight, the overworked crew collected a wealth of ultraviolet data from mysterious and little-known objects in the Universe.

Soyuz 7K-TM variant for the US-Soviet joint mission

A specialized version of the Soyuz spacecraft originally known as 7K-TM was custom-designed for the joint mission with the US Apollo spacecraft in 1975. It was equipped with a new type of a docking port dubbed APAS for Androgynous Peripheral Attach System.

Kosmos-638: First rehearsal of a joint mission with Apollo (INSIDER CONTENT)

On April 3, 1974, the USSR launched an unpiloted test version of a modified Soyuz vehicle, which it hoped to eventually use for an orbital docking with the American Apollo spacecraft. Despite the international nature of the project, the introduction of the new variant was shrouded in usual Soviet secrecy and was barely documented in history books.

Soyuz-14: The USSR launches first military station crew

On July 3, 1974, the Soyuz-14 mission carried what was announced as an expedition to the newly launched Salyut-3 space station. In fact, it was a specialized military team heading to the Almaz OPS-2 orbital observation outpost publicly camouflaged behind the civilian space station program. For the first time, a piloted military orbiter armed with a self-defense gun and an array of reconnaissance equipment operated in space.

The USSR develops new variant of the Soyuz spacecraft — 7KS

Fast-paced upgrades of the Soyuz spacecraft in the early 1970s included work on the most-advanced version of ship at the time, called 7K-S, initially conceived for the military. It never reached operational status but paved the way for the 7K-ST variant (Soyuz-T) which became the workhorse of the Russian piloted space program in the 1980s.

The USSR launches Soyuz 7K-S variant (INSIDER CONTENT)

On Aug. 6, 1974, the USSR secretly launched an experimental version of the Soyuz spacecraft that opened a years-long flight test program that would lead to the Soyuz-T variant. The first mission, which lasted two days, was announced under the cover name Kosmos-670, but its true objectives were not acknowledged until the end of the Soviet period.

The USSR tests Soyuz for joint mission with the US (INSIDER CONTENT)

The original test flight program of the Soyuz 7K-TM variant, developed for the Apollo-Soyuz docking mission, envisioned one unpiloted launch and two dress rehearsal missions with cosmonauts onboard. However, numerous technical problems and equipment delays hampering the first test flight in April 1974 prompted Soviet officials to add another pilotless launch in August of the same year. It lifted off without much fanfare under the cover name Kosmos-672 on Aug. 12, 1974.

The Soviet military crew fails to reach its orbital post

On Aug. 26, 1974, the USSR launched the second expedition to the Almaz OPS-2 military space station, operating in Earth's orbit under the cover name Salyut-3. However, commander Gennady Sarafanov and flight engineer Lev Demin failed to dock their Soyuz-15 spacecraft to the outpost, narrowly avoiding a high-speed collision. The crew then urgently headed home after just two days in orbit.

Salyut-4: Finally a breakthrough

On Dec. 26, 1974, the USSR launched its sixth attempt to establish habitable base in orbit, taking into the account four years of very difficult experience in launching and operating such complex vehicles. This time, the space station, publicly announced as Salyut-4, worked well, setting the stage for a very busy year in space.

First expedition on Salyut-4

On Jan. 11, 1975, just three weeks after the launch of the Salyut-4 space station, the USSR orbited its first crew slated to occupy the outpost for nearly a month. During their expedition, members of the Soyuz-17 crew overcome a series of technical challenges to conduct pioneering research in orbit.

Cosmonauts escape a close call at launch

On April 5, 1975, the second crew heading to Salyut-4 went through a near-death experience when their rocket failed just short of orbital velocity, triggering dangerous fall back to Earth and a risky recovery operation in the mountainous terrain near the hostile border with China.

Second expedition to Salyut-4

The two-month trip of the Soyuz-18 crew to a space station in 1975, which broke a Soviet flight-duration record, is also widely credited with setting standards and procedures for progressively longer stays of Soviet cosmonauts aboard Earth-orbiting outposts for years to come.

Apollo-Soyuz project, ASTP

In July 1975, the Soyuz-19 spacecraft with two cosmonauts onboard and the US Apollo vehicle with three NASA astronauts conducted a successful rendevous in the orbit around the Earth, becoming a symbol of a short-lived detente period in the Cold War.

The USSR repeats the Soyuz 7K-S flight test

On Sept. 29, 1975, the second experimental version of the Soyuz spacecraft, later known as Soyuz T, secretly entered orbit without a crew. The mission was announced under the cover name Kosmos-772, but its details remain largely unknown until this day.

Soviet and Russian space station launches:

Soviet launches related to space station projects and solo Soyuz flights in 1971-1985:

Next chapter: Mir space station

This page is compiled and maintained by Anatoly Zak

Last update: September 29, 2025

All rights reserved

An early Soviet concept of a space station formulated at TsNIIMash research institute.

Soyuz launch to the Salyut-1 space station. Credit: RKK Energia

A possible view of the first Salyut space station in orbit. Credit: RKK Energia

After the loss of the first crew of the Salyut space station during landing, pressure suits (right) were introduced for launch, landing and docking operations. Standard Pinguin suits (left) were worn during work inside the station. The equipment shown was used during the Interkosmos program in the late 1970s. Copyright © 2001 Anatoly Zak

The DOS-7K No. 2 space station.

Scale model of the second-generation Salyut space station, which included independently guided solar arrays. Copyright © 2001 Anatoly Zak

The US Apollo and the Soviet Soyuz spacecraft docked for eternity in the Smithsonian Air and Space Museum in Washington, D.C. Copyright © 2002 Anatoly Zak

A 3rd generation Salyut space station, differed from its predecessors by a second docking port and a capability to be refueled in orbit from Progress cargo ships. Copyright © 2001 Anatoly Zak

A scale model of the 3rd generation Salyut space station docked with two transport spacecraft -- the Progress cargo ship and the Soyuz manned spacecraft. Apparently, no photos of such configuration exist. Copyright © 2001 Anatoly Zak

The Orlan spacesuit, which had been used onboard the Mir space station. Copyright © 2001 Anatoly Zak

To negate influence of weightlessness after long-duration flights, the Salyut crewmembers were wearing Chibis suits at the end of their missions. The Chibis suits create low-pressure in the lower parts of the body, driving more blood toward legs as caused by gravity on Earth. Copyright © 2001 Anatoly Zak