Salyut: How We Learned To Make Space Stations

When you think about space stations, which ones come to mind first? You might think Skylab, the International Space Station (ISS), or maybe Russia’s Mir. But before any of those took to the heavens, there was Salyut.

Russia’s Salyut 1 was humankind’s first space station. The ensuing Salyut program lasted fifteen years, from 1971 to 1986, and the lessons learned from this remarkable series of experiments are still in use today in the International Space Station (ISS). The program was so successful at a time when the US manned space program was dormant that one could say that the Russians lost the Moon but won the space race.

Russia’s Own Space Race

Almaz space station
Almaz space station

The Salyut program’s origins stem from a little know space race within Russia in the 1960s. On the one side was the OKB-52 design bureau which worked on putting up a military space station. On the other side was the OKB-1 which sought to do the same but for civilian science purposes.

The military had an early lead with their Almaz space station cores. In an effort to catch up, the civilians combined the Almaz hull with their own systems from their Soyuz spacecraft and added more solar panels. These were designated DOS (Durable Orbital Station) stations.

The civilian Salyut program was created on February 15, 1970. With the cold war in full swing, the military program was masked from the world by pretending to be a part of Salyut. And by April 19, 1971, the first of the Salyuts and the world’s first space station was launched.

Salyut 1 (DOS-1): Firsts And Tragedy

Salyut 1 and Soyuz spacecraft
Salyut 1 and Soyuz spacecraft

In contrast to today’s space stations made up of multiple modules, the first Salyuts were monolithic. They were launched as a single unit, filled with all the supplies they’d need as well as all their experiments. The crew arrived separately and when all supplies were exhausted and the experiments done, the space stations were deorbited.

While the Salyut 1 missions held a lot of firsts, they were not without some difficulties. On April 22, 1971, the first crew went up in Soyuz 10 but were unable to enter the station and had to abort the mission.

The second crew in Soyuz 11 successfully entered the station and remained for 23 days, a new record for duration in space at the time. However, tragedy struck during the crew’s return to Earth when a pressure-equalization valve between the Soyuz spacecraft’s orbital and descent modules opened prematurely while still in space. The three cosmonaut’s died of asphyxiation within seconds. To date, they are the only people to have died in space. (For the quibblers, the Columbia disaster occurred around 60 km, and most consider space to start at 100 km.) A redesign of the Soyuz followed with room for only two cosmonauts, but wearing pressure suits.

Setbacks And Military Missions

As is the norm for space travel, the still infant civilian program continued to suffer setbacks.

DOS-2 would have been Salyut 2 before the second stage of its Proton rocket failed causing it to crash into the Pacific. The designation Salyut 2 was instead given to the first military mission using an Almaz space station. DOS-3 was to become the next civilian Salyut, but errors in its flight control system while out of range of ground control led to unnecessary orbital corrections, using up all of its fuel. As a result, the Salyut 3 designation went to the next military mission with another Almaz station. The final military mission was called Salyut 5.

Salyut 4 (DOS-4): Doing Science

Salyut 4
Salyut 4

The next civilian station, Salyut 4, was essentially a copy of DOS-3. It had three large solar arrays instead of Salyut 1’s two sets of two, generating two kilowatts. Scientific instruments included a solar telescope, shortwave diffraction spectrometer, and two X-ray telescopes. It was also outfitted with equipment for testing and minimizing the effects of zero-gravity on humans.

Two crews spent time on board, the second crew staying for 63 days. A third was planned but experienced a launch abort. An unmanned Soyuz spacecraft also docked to the station for three months to test durability.

Salyut 6 (DOS-5): The Next Generation

Salyut 6 with Soyuz and Progress spacecraft docked
Salyut 6 with Soyuz and Progress spacecraft docked. (fair use image)

Salyut 6 heralded in the next generation of space stations, ones which permitted continuous occupation and could remain in space for long durations, two things which today we think of as normal with the ISS.

Continuous occupation and long durations were made possible mainly by the addition of a second docking port. Previous Salyuts could neither be resupplied nor could their waste be removed, except for that which could be carried in the limited space in the crewed Soyuz spacecraft. A new spacecraft, the unmanned Progress freighter, was created for carrying supplies to the stations. Supplies included air, air regenerators, food, water, clothing, mail, and propellants. Waste was loaded back into the Progress to be burned up on reentry into the atmosphere. Progress vessels are still in use today, making three or four resupply trips to the ISS each year.

You might wonder why you couldn’t use a single docking port for resupply. Why couldn’t you temporarily undock the crew-carrying Soyuz from the station, dock and unload the Progress, and then redock the Soyuz? One reason was made clear a few years later on the Mir space station during terrifying moments when a Progress docking went very wrong. It missed the docking port and instead collided with some solar panels and one of the Mir’s modules, creating an air leak.  Luckily they were able to seal off the leaking module but if things had gone a little differently, they would have had to abandon the station. If they had only one docking port, their escape vehicle, the Soyuz, would have been temporarily undocked to make room for the errant Progress freighter. Not good. With two docking ports, the Soyuz was ready and waiting.

The two docking ports also allowed for visitors and for crew handovers, where a new crew would arrive while the previous was still present. The Salyuts never were occupied continuously, but this was the beginnings of such a possibility.

Launched in September 1977, Salyut 6 was deorbited in July 1982 after five years of use. It accommodated five long-duration crews and eleven short-term ones. It could have been used longer, but managing mold in the living compartments had become too difficult.

Salyut 7 (DOS-6): The Final Voyages

In his Diary of a Cosmonaut: 211 Days in Space, Valentin Lebedev talks about how the experience built up from the five years of crews in Salyut 6 led to many changes to the interior of Salyut 7. To start with, the equipment was completely rearranged for more efficient work, service, and repair. They now had a variety of food to choose from as well as improved medical equipment.

The portholes now came with external shutters to keep them clean of fuel from the engines and to protect them from micrometeorites. Similar shutters are used today on the International Space Station to protect the Cupola module’s large windows from micrometeorites.

On Salyut 6, water was brought up in fifteen-kilogram spherical tanks which had to be hand-carried from the Progress supply ship into the Salyut. At least one crew hacked this system by running hoses from the Progress through the docking port to pump water directly into the Rodnik water storage system. This improvement was built into Salyut 7 and later into Mir.

Perhaps most significantly, Salyut 7 started the move from monolithic space stations to modular ones. To help with the design of Mir, testing was performed with docking and making use of “Heavy Cosmos modules”, which were really Russian TKS spacecraft.

Even as Mir began its life in 1986 Salyut 7 was to remain in use, and the station was raised to a higher storage orbit. But with the collapse of the Soviet Union and its ensuing economic difficulties, funding for the station never materialized and the last Salyut’s orbit gradually decayed until 1991 when it underwent an uncontrolled reentry over South America.


We’ve already mentioned a number of things that carried over from the Salyut program, including external window shutters, the Progress resupply ships, and the whole concept of modular space stations. But even modules still in use today are descendants of the Salyuts. Mir’s Code Module was a DOS-7. The Zvezda Service Module on the ISS is a DOS-8. The ISS’s Zarya module is a descendant of the TKS spacecraft tested with Salyut 7.

What other cold war era Russian tech echos into the present day? The powerful RD-180 rocket engine is a modern version of the closed-cycle engine design used for the Russian N-1 moon rocket. Read all about it in [Kristina Panos’s] article Russian Rocket Tech Comes in from the Cold.

61 thoughts on “Salyut: How We Learned To Make Space Stations

  1. Many were one visit stations, and at least one(Almaz) had a 23mm Nudelman aircraft canon only fired after the station was evacuated at the end of mission and a manned reconnaissance telescope system similar to the unlaunched US MOL.
    With Salut 1 though they boosted the orbit, something we never bothered to do with the brilliant and very large Skylab with the troubled STS not getting into service in time. So sad that the US turned those last three paid for and ready to launch Saturn Vs into gravestones to our former ability to send humans beyond LEO, at a minimum they could have been three more Skylab modules.

    1. There was a flight qualified second Skylab, but it now sits in the Smithsonian Air and Space Museum with holes hacked through it for the observation walkways. Worse are the training simulators, one is likely still sitting outside where it was moved after restoration work was stopped. When the tarp went bad the museum where it’s located wouldn’t allow volunteers to do anything with it, not even just supplying and installing new tarps to protect it.

  2. I love the Soviet space program. Their spacecraft have this continuous string of design running through them, like a brand. Look at a Soviet probe or station or launch system and you instantly recognize where it comes from. It reminds me of playing a real-time strategy game, where each faction has their own visual motifs and theme. For the Soviets that theme was solid.

    Salyut-3 has the distinction of being the only known armed spacecraft, although there were certainly more during the cold war. It had a 14.5mm automatic cannon bolted to the hull. No turret; the whole 20-ton station had to fire its attitude thrusters to bring the little gun to bear on a target. And with an expected effective range of only 2 miles, you really had to wait until you saw the whites of their eyes. 2 miles would be fantastic on the ground, but space obviously has a thing about distance. Cosmonauts also occasionally carried 9mm handguns or the TP-82 to fight off bears in Siberia after they de-orbited, which is about as Russian as it is possible to be.

    1. I wish the shuttle had a continuous improvement program like Soyuz.

      It is also a shame that the Mercury & Gemini spacecraft were abandoned after their primary mission was completed. Both could of used any booster with sufficient power. They might of been any number of missions requiring one one or two crew members to accomplish. It just seems like the US always starts with a clean sheet of paper when the basic hardware is both proven and sound. Just make design updates (composites where it makes sense, and of course update the avionics).

      1. Same here I think if they built improved orbiters and added liquid boosters would have became the safe and reliable vehicle it originally was intended to be.
        Apollo also was killed off too soon as I think it could have served well into the 1980s with upgrades.

        1. It wasn’t that they couldn’t have continued to use Apollo from a technical standpoint, it was the cost. At around $1bn per launch (at current rates) it wasn’t sustainable, especially in the political climate of the time.

          1. I think for some kind of common goal for the World and really long term survival… space stations are a noble venture. More realistically I think there can be undersea and more underground developments with plants and pro-biotics along with humans and other animals first and foremost from an investment standpoint and to advance technologies as well as study social issues like found in the biosphere projects and non military trained operations in submarines first.

            I also think the older U.S. gentlemen may have observed this in regards to our original investment in communications, surveillance and reconnaissance operations versus having people in space for longer periods of time. Seems kind of mentally ill to me at this point in time of humanities development other than maybe to study effects of how humans can become healthier in lower gravity environments as well as healthier in that dangerous of an environment in general.

            We really need to have more robotics operations in space and less people other than maybe for recreational at non public investment expense. Seems like a waste of money. Seems we need to clean up all the space junk also and problems on earth more with the billions.

            I personally feel the travel to Mars is like a promotion of assisted suicide and high risk civil activities propaganda agenda that isn’t smart for the U.S. future as we can tell by the performance metrics if anyone looks.

          2. A second order of Apollo hardware would have been cheaper than the first since the tooling was paid for besides there was a lot they could have done to reduce costs such as using the Saturn V-B for crew launch and making the Apollo capsule reusable.
            Instead the administration at the time would rather throw money down the toilet known as the war on drugs.
            Nixon’s cuts also crippled Apollo’s successor the Shuttle to the point we may have actually been better off simply improving the old hardware.

          3. I’m guessing the programs with the Paperclip and other POW’s were too dangerous since they were all addicted to DI-X and alcohol for the most part. Before WWII the enforcement of the Mann Act, Harrison Act, Pure Food and Drug and Pure Food, Drug and Cosmetics Act had cleaned up the population for the most part in the U.S. That changed after the NSA of 1947 after the new inbred junkies were brought in, learned our systems (and vulnerabilities) and started using our systems for nefarious operations.

          4. Apparently DI-X wasn’t put into mass production (or so THEY say), but it sounds like some groovy stuff. A decent hit of oxycodone, cocaine, and methamphetamine, all nice and orally active in a pill.

            Still it’s nothing you couldn’t conjure up yourself now after a couple of hours on the streets assembling the component drugs. It was just a mixture of all 3.

            Alcohol, cocaine, opiate and amphetamine addictions can all be treated. And addiction depends very much on the individual and their circumstances to set in. Most people just don’t fancy being addicted to anything. And being a high-up Paperclip, you’d surely have the political and scientific knowledge to know what you were doing. Sure, maybe some developed addictions anyway, but they’re easily kept at bay with maintenance doses, or slowly reducing if that’s what you want.

            Sure there’s a chance the patient will score on the street instead, but how easy is that in 1947 for a bunch of Nazis? If anything, an easily pulled chemical chain around the neck would be a nice easy way of bringing them back into whatever desired behaviour.

            That’s just the mechanics of it, I’ll leave the utter paranoia for someone else to argue with.

            The Mann act dealt with prostitution and any other sort of “immoral” sex, but yep thanks to Harrison, nobody in the USA takes any other drugs than those the doctor gives them. All cleaned up by 1947.

      2. The shuttles were continually improved. Newer shuttles had better technology, and lots of stuff was retrofitted to the older ones. Using lithium alloys to make the external tank much lighter is one off the top of my head. Of course they did. NASA is full of researchers and spaceship designers, they don’t pay them to play Scrabble all day.

        Similarly Apollo technology evolved into Shuttle tech, and later stuff. All technology evolves, NASA are no different, and certainly not stupid.

        As far as Gemini and particularly Mercury, those were outdated designs based on the technology they had at the time, miles behind the progress they’d made even in a few short years in the 1960s. If you’re going to go to all the expense of a rocket, never mind a crew’s lives, isn’t it sensible to send up the newest and best capsules you can make?

    2. >”And with an expected effective range of only 2 miles”

      Why “effective range”? There’s no air resistance in space, so the question of killing someone or something is a question of aim, or luck, or using a shotgun shell.

      1. Accuracy and the farther away the target it the more time it has to get away.
        The path will still curve and become harder to calculate and a target with a good amount of delta V may have enough time to move out of the way of the bullet.

    3. I agree. Continuous small improvements, always building on the previously proven, was a Soviet way. Maybe also Russian today.

      Stark contrast to the US efforts where it seems they always start off with a clean sheet. And repeat many mistakes, because they think they are always smarter in every aspect than the guys/girls before them.

      1. Most of the guys and girls are the same people who designed the previous stuff. They’re smarter cos they learned from the experience of the older stuff. There’s no point in reinventing the wheel, but plenty of progress in space technology as time goes on.

        NASA don’t reinvent wheels, but they take the opportunity to try new things out as they think of them, and learn from the past. It can be argued that the whole point of the space programme is to research a future, better programme. That will do more things, better. Once we’ve got bases on other planets, then the space programme will have moved past the first stage.

    4. “Salyut-3 has the distinction of being the only known armed spacecraft”
      Not quite…there was also the Polyus, which some describe as the first and only space battlestation…in reality it was a test of a megawatt CO2 laser that was to be in orbit.
      It launched using the Energia rocket (which unlike the Space Shuttle could do missions without the orbiter) on it’s maiden mission, weighed 80t and was 37×4.1m (close to the size of a Falcon first stage)
      As luck (or lack thereof, depending which side of the Iron Curtain you were on) would have it, while Energia itself did it’s job perfectly, the station failed complete it’s injection burn (it had to be placed “upside down” on the rocket, so in order to start the injection burn at all, it had to turn 180°) and reentered, causing it’s destruction.
      That’s just to give you the idea of what would the Cold War turn into had the Soviet Union no collapsed – real Star Wars :P

      As for the bears – that actually never happened, but better safe then sorry.
      There were several instances where the search and rescue teams couldn’t reach or find the landed craft because of adverse weather, so the cosmonaut(s) just !walked! a few miles to the nearest village, where they’d find shelter, food and “call home”.
      It would really suck if the “hero of the Soviet Union” (actual title that many cosmonauts received) survived all the dangers of space travel, only to be eaten by a hungry bear ;-)

      1. Yeah, I wrote up a big paragraph about that, as well as some about the autocannon which TGT mentioned. I cut both for length. This article could have been much longer. The Salyut program was rich with interesting technology and events.

        1. Say what you will about the russian space program, but they had some serious balls to try and hard-dock with a dead spacecraft to attempt a rescue and repair.

          For all they knew, it could have decided to kill them a million different ways.

        1. Actually, movie far from real events, directors as always showed own vision of event plus a lot of fake drama (guy which throw chair in glass in real life was the most calm guy, militaries not planned to shot down station and even had no possibility to do that yet, americans not planned to steal station, wives not hated space and not cry everywhere, nobody drank vodka, emergency situations was absolutely another and fixed in another way, etc.). Cosmonauts was so angry, that deny to use names in movie. So, you can perceive movie just like sci-fi which far based on real events.

          You can watch movie with english subtitles alreday now, not hold it in some list, just to google site sovietmoviesonline (after half movie it will ask subscription, but clear cookies/open directly and watch for free). Also I can recommend else one movie, about first spacewalk: “Time of Pioneers”. It more close to actual events.

  3. As a bit of a trivial, MIR had an orbital sauna, which the crew used for cleaning themselves.
    >”Mir featured a shower, the Bania, located in Kvant-2. It was an improvement on the units installed in previous Salyut stations, but proved difficult to use due to the time required to set up, use, and stow. The shower, which featured a plastic curtain and fan to collect water via an airflow, was later converted into a steam room”

    The sauna used too much energy, so they dismantled it and started using wet wipes instead.

    1. Although the legend goes that the crews liked the sauna so much they refused to take it apart, citing workload as the reason why they didn’t complete this “secondary objective”, so after the first and second crew refused to take it apart, the soviets sent up a third crew with a political officer whose main mission was to dismantle the sauna.

    2. I think a good idea would be a big plastic bag, man-size. Fill it full of warm water, strap some soap to your hand, and scrub away. For safety probably wise to keep your head sticking out the top, zipped around the neck. Then another fill of water for the rinse cycle, and there you go. You could even have a third cycle of warm air for drying, to keep the moisture inside.

      Or you could do something similar on a smaller scale. A hand-sized thing with a water jet, a sponge with a supply of soap piped to it, and suction to remove it. The whole thing is within a sort of cup, that you press on the body. It washes you a few square cm at a time.

      Much wiser than an open, 1G-style shower with a water spray at the top, and bloody ginormous fans at the bottom. Surprised they didn’t put more thought into it. I’m thinking particularly of Skylab here, but I don’t think astro-showers have improved much in the decades since.

  4. Thanks for the writeup. I have always found the Soviet space program fascinating, given that their goal seems to always have been political status and military might, with only a veneer of pure science thrown in. Unlike the US program(s) that had a much more precarious balance to deal with, this focus allowed them to make design choices that in some cases were excellent (e.g. the Progress capsule). (I’m ignoring the Buran STS clone as it belongs in the let’s-see-if-it’s-a-good-idea bucket.)

    On the downside, the Soviet program also had its sinister side, with weaponization of space assets — or at a minimum preparation for it — being an integral part of their efforts.

    1. “I have always found the Soviet space program fascinating, given that their goal seems to always have been political status and military might, with only a veneer of pure science thrown in.”

      So, quite similar to the U.S. space program then.

      1. “So, quite similar to the U.S. space program then.”

        Only if you suffer from myopia.

        In the Soviet program the military and political considerations drove the programs, with everything else needing to find a niche to catch a ride if they could.

        In the US program military funding was critical for several systems, but NASA drove civilian goals independently with a relatively large budget to back it up. For example, quite a few of the ugly duckling aspects of STS were ultimately caused by the mixed goals between the civilian and military requirements. Had STS been driven by either side independently we might’ve had a more lasting system.

          1. Don’t forget about what started the ball rolling like say with the X-15 Program and Project Lunex and Project Horizon. Mission objectives can be strange… though don’t think NASA is purely civil service. They warehoused some of the murderous deadliest also. CIA/NASA anyone?

          2. Ah, I knew ARPA (now known as DARPA) was in the mix leading for the U.S. and found the Project Orion when looking for the first nuclear power plants info:

            Interesting is the idea was first proposed by Russian explosives expert Nikolai Kibalchich in 1881. Man, rough being an inventor in the revolutionary period there. Confusing all the different factions of socialists too.

    2. Sounds like you only heard the superficial presentation of their program that the west pushed.
      And that stuff is still going on, you see the Chinese making discoveries, then being ignored, then 2 or more years later when the US discovers the same thing they just blatantly bill it as a first in all the news presentations, including on sites dedicated to space/science. But that might also be part of the modern acceptance of having ‘a short memory’ for the sake of clicks and headlines I guess.

  5. On being eaten by bears, J.G Ballard’s chilling story “A Question of Reentry” from the early 60’s has the astronaut landing off target in the South American rainforest and being viewed as a god by the primitive natives. But the final line of the story is “They eat their gods”.

  6. Got mold in your space station? Fog it with chlorine dioxide. Kills the growing mold and the dormant spores. On Earth you just have to let it settle for a few hours then open doors and windows to ventilate. It doesn’t leave anything toxic behind.

    In space it would most likely need all the air run through a filter/capture system to collect any leftover – but the mold would be completely gone. I fogged under a house several years ago, was a lot of mold on the floor joists and boards. After fogging there was no visible mold, still isn’t.

    1. Galane: Do you remember what chlorine dioxide product did you used? Looks like Home Depot even has a product now days.

      I’ve been using industrial strength ozone though was planning to do a more intense fumigation, once I clean more water damage stuff out, with chlorine dioxide since kills spores and eggs also just in case. I don’t think the ozone is as effective at spores and eggs.

    1. Apparently, yes, even more first’s in space and I think even the first thermonuclear power plant in space that was external combustion… I may be wrong as those may have been used on remote ground stations in the USSR and the US was the first with the nuclear power plant systems even though some had to be recovered in the ocean from failed launches.

      I notice that IR and thermal imaging isn’t noted as well as other potential imaging firsts that seem contradictory to other information or maybe the targets were not terrestrial reported.

      I want to say the thermal imaging satellite is how the USSR found out about our (US) secret aircraft from thermal images left in the ground when satellites flew by Area 51.

      1. Still not finding the USSR thermonuclear external combustion power plants. I’m confident they had tracking or weather or communications stations that may have been filled with another gas initially like hydrogen/helium… though ran on air after the gas leaked out so were an air medium type.

        I did find this info where some of the first U.S. reactors were Mercury Rankine Cycle (yuck) and thermoelectric:

  7. Sentence regarding RD-180 is totally wrong! It’s predecessor was designed for Energia launch vehicle decade later by competitive design bureau. Most probably they took into account negative experience of they competitors. Engines manufactured for N-1 were NK-33 reworked to AJ26-58 by Aerojet for Antares rocket. Finally, Antares was re-motored with RD-180 which is much more reliable.

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