Space Stations: Salyut, Mir & the International Space Station

History of Space Exploration

Chapter 8 · Space Stations: Salyut, Mir & the International Space Station

After the Moon landings and alongside the Shuttle (Chapters 5 to 7), a second line of development was the space station, a place to live in orbit for weeks, then months, then years. This chapter follows it from the first station, Salyut 1 in 1971, through Mir, to the International Space Station. The sources are three reference articles. They give dates and sizes clearly, and they give few costs, so the chapter says where money is missing.

Salyut 1 (1971)

Salyut 1 (DOS-1) launched on 19 April 1971 and is described as "the world's first space station." The source says the Soviets shifted focus to orbital stations after Apollo 11's landing, seeking to outpace the American Skylab programme. I did not find what Skylab was at this point in the source, so the chapter does not explain it.

The Soyuz 11 Tragedy The Soyuz 11 crew, Georgy Dobrovolsky, Viktor Patsayev and Vladislav Volkov, docked and spent 23 days aboard conducting experiments. The source says "a pressure relief valve had malfunctioned during reentry leading to a loss of cabin atmosphere." The crew, lacking pressure suits, asphyxiated, and became "the only humans to die above the Kármán line." The disaster prompted a mandatory redesign: all further Soyuz missions would require pressure suits during launch, docking and re-entry.

What I Cannot Add The source does not say how the fault was found, when the crew died in the sequence of re-entry, or how the crew reacted. It also does not define the Kármán line. I report the phrase as written and do not give a height for it.

The Programme

The Salyut programme produced seven stations in total. Salyut 1's mission ended in October 1971, and later stations such as Salyut 6 and Salyut 7 achieved greater success.
The final module, Zvezda (DOS-8), became "the core of the Russian Orbital Segment" of the International Space Station.
The Soviet military operated parallel Almaz stations (Salyut 2, 3 and 5), and Salyut 1 was adapted from Almaz designs but repurposed for civilian science.

Mir (1986 to 2001)

Mir launched on 20 February 1986 and was deorbited on 23 March 2001 after "funding was cut off." The source gives 15 years of operation, 12.5 years of them continuously occupied.

Feature	What the source says
Modules	Seven pressurised modules assembled over a decade: the Core Module, Kvant-1, Kvant-2, Kristall, Spektr, a Docking Module and Priroda.
Size	About 130 tonnes, 19 metres long by 31 metres wide.
Orbit	86,331 orbits at an inclination of 51.6 degrees, about 15.7 times a day at altitudes of 354 to 374 km.
Visitors	105 cosmonauts and astronauts from 12 nations.
Record	Valeri Polyakov holds the "longest single human spaceflight," 437 days on the station from 1994 to 1995.
Cost	An estimated "$4.2 billion over its lifetime."

Cooperation and Trouble

The Shuttle-Mir programme involved "eleven Space Shuttle missions" and enabled an extended American presence on the Russian station. The source calls it a major Cold War thaw in space cooperation. The 1997 collision with the Progress M-34 vehicle damaged the Spektr module severely, and fire incidents also occurred.

Collisions and Fires, Not Described The source names the 1997 collision and fires in a sentence each. It does not say who was aboard, what was lost or whether anyone was hurt. Following the Soviet dissolution, Russia struggled financially, and the programme became unsustainable. I did not find how the decision to deorbit was made.

Links Back Chapter 3's Sputnik and Chapter 4's Vostok belong to the Soviet line that produced Salyut and Mir. The source does not connect them, and I do not claim a continuous programme. The Shuttle-Mir cooperation contrasts with the rivalry of Chapters 3 to 6, and the sources do not say why the change happened.

The International Space Station

Five agencies operate the ISS: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan) and CSA (Canada). The source says fifteen countries are involved, making it "the most politically and legally complex space exploration program in history."

Feature	What the source says
First module	The Russian-built Zarya module launched on 20 November 1998.
Continuous occupation	Began on 2 November 2000 when Expedition 1 arrived, and the article says "25 years and 323 days" as of its update.
Scale	109 by 73 metres, a pressurised volume of 1,005 cubic metres (comparable to a Boeing 747), and a total mass of 450,000 kg.
Visitors	"As of August 2025, 290 individuals from 26 countries had visited the station."
Research	Microgravity experiments, materials science, astrobiology, space medicine and Earth observation, with the Alpha Magnetic Spectrometer as a flagship dark-matter experiment.

Threads From Earlier Chapters The Shuttle (Chapter 7) took part in building the station, and the Soviet Zvezda module is its core Russian segment. After Columbia, the source in Chapter 7 says the fleet was to finish the station and retire. So the station is where both lines of development meet. That is my synthesis of separate articles, and no source says it.

The Future

The station remains operational "until the end of 2030," after which de-orbiting is planned with the US Deorbit Vehicle. The source adds that "critique of this plan and the proposal of parking the station at a more stable higher orbit has gathered congressional support."

Cost Is Missing The source says rising costs forced more international participation, and gives no budget figures. So the chapter cannot compare the station's cost with Mir's $4.2 billion or with the Shuttle programme's $211 billion (Chapter 7). Any such comparison would need figures from another source, in matching dollars.

What I Did Not Verify I did not find Skylab, Tiangong or China's stations, the political negotiation of the ISS, what has been learned from the research, the crews' daily lives, or the reasons for the 2030 date. I also did not check the "25 years and 323 days" figure against the launch date, which depends on the day the article was updated.

Hands-On Exercises

Exercise 1

Make a table of Salyut 1, Mir and the ISS with launch date, end or planned end, and one fact each, using only the chapter.

→ Solution

Exercise 2

A student writes "The Soyuz 11 crew died in space." Use the chapter to state exactly what the source says.

→ Solution

Exercise 3

Say why the chapter cannot rank the three stations by cost, and what you would need to do so.

→ Solution

Quick Reference

Salyut 1: 19 April 1971; first station; Soyuz 11 crew (23 days aboard) died on re-entry; pressure suits required afterwards
Mir: 20 February 1986 to 23 March 2001; about 130 tonnes; 105 visitors; Polyakov 437 days; 1997 collision; $4.2 billion
ISS: Zarya 20 November 1998; occupied since 2 November 2000; five agencies, fifteen countries; operations to the end of 2030
Cost: no ISS figure in the sources
Not covered: Skylab, China's stations, the ISS negotiations