Space Stations Through History: Salyut to Starlab

Humanity has maintained a continuous presence in low Earth orbit since November 2, 2000, when the first crew boarded the International Space Station. But the story of orbital habitation began three decades earlier, with a series of stations that were as much about geopolitics as science. From Salyut to Starlab, here is the complete history of space stations, and where they are headed next.

The Salyut Era (1971-1986)

The Soviet Union launched Salyut 1 on April 19, 1971, the world's first space station. It was a single module, roughly 20 meters long and 4 meters in diameter, with enough room for a three-person crew. The first crew to successfully board it, Soyuz 11's Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, spent 23 days aboard conducting experiments. Tragically, all three cosmonauts died during reentry when a valve failure depressurized their Soyuz capsule.

The Salyut program continued through seven stations, divided between civilian (DOS) and military (Almaz) variants. Key milestones included:

• Salyut 4 (1974-1977): First station to host crews for extended durations, with missions lasting up to 63 days
• Salyut 6 (1977-1982): Featured two docking ports, enabling crew rotation and resupply by Progress cargo vehicles, a logistics model still used today
• Salyut 7 (1982-1991): Hosted crews for up to 237 days and demonstrated that humans could live and work in space for months at a time

Skylab: America's First Station (1973-1979)

NASA's Skylab launched on May 14, 1973, built from a converted Saturn V third stage. At 77 tonnes, it was far larger than any Salyut station, with about 352 cubic meters (12,417 cubic feet) of pressurized volume. Three crews visited Skylab over 1973-1974, conducting solar observations, Earth science, and biomedical research.

Skylab proved that astronauts could perform productive scientific work in microgravity for months. It also demonstrated the challenges of station maintenance: the first crew deployed a parasol-like replacement sunshade through a small instrument port from inside the station, after its micrometeoroid shield tore off during launch. NASA had planned to reboost Skylab using the Space Shuttle, but delays in the Shuttle program meant the station reentered the atmosphere in 1979, scattering debris across Western Australia.

Mir: The First Modular Station (1986-2001)

The Soviet Union's Mir station represented a generational leap. Launched in 1986, Mir was the first modular space station: a core module with six docking ports that could accept additional specialized modules over time. By 1996, Mir had grown to seven pressurized modules and about 130 tonnes, with dedicated laboratories for materials science, Earth observation, and astrophysics.

Mir set records that stood for years: cosmonaut Valeri Polyakov spent 437 consecutive days aboard in 1994-1995, a record for the longest single spaceflight that still stands. The station hosted 28 long-duration crews and numerous visiting crews from 12 countries, including seven NASA astronauts during the Shuttle-Mir program. Despite a serious fire in 1997 and a collision with a Progress cargo vehicle that depressurized one module, Mir operated for 15 years before being deliberately deorbited in 2001.

The International Space Station (1998-Present)

The ISS is the largest and most expensive structure ever built in space: 420 tonnes, spanning 109 meters tip to tip, with a pressurized volume of 1,005 cubic meters. It represents the combined effort of 15 nations, led by NASA, Roscosmos, ESA, JAXA, and CSA. Assembly began in 1998 with the Russian Zarya module and continued through over 40 assembly flights over more than a decade.

The station has been continuously occupied since 2000 and has hosted 298 people from 26 countries. It serves as a platform for thousands of scientific experiments in microgravity biology, materials science, Earth observation, and fundamental physics. The ISS has also become a proving ground for commercial space activities, with companies like Nanoracks, Axiom Space, and SpaceX conducting commercial research and crew missions.

The ISS is currently funded through 2030, with NASA planning to deorbit the station using a SpaceX-built deorbit vehicle. The transition to commercial successors is already underway.

Tiangong: China's Independent Path (2021-Present)

China's Tiangong space station, completed in 2022, represents the only other operational multi-module station in orbit. At approximately 100 tonnes, it features three modules: the Tianhe core module and the Mengtian and Wentian laboratory modules. Tiangong hosts three-person crews on six-month rotations and conducts a growing portfolio of scientific research. In October 2023 China announced a roadmap to expand Tiangong to six modules, beginning in 2027.

The Commercial Station Era (2025-2035)

With the ISS approaching retirement, a new generation of commercial space stations is emerging:

• Axiom Station: Axiom Space plans to send its first module, the Payload, Power and Thermal Module, to the ISS, from which it could depart as early as 2028 to become a free-flying station
• Starlab (Voyager and partners): A single-launch station designed for both NASA crew and commercial customers; it completed NASA's commercial critical design review in February 2026
• Orbital Reef (Blue Origin/Sierra Space): A mixed-use business park in LEO with modules for research, manufacturing, and tourism
• Vast Haven-1: A single-module commercial station that Vast says is on track to launch in the first quarter of 2027, as a pathfinder for the larger Haven-2

These stations will serve multiple markets: NASA crew rotations, national space agencies without their own stations, pharmaceutical and materials research, media production, and space tourism. The transition from government-owned to commercially-operated stations mirrors the broader shift in the space industry toward public-private partnerships.

Track the evolution of orbital habitation, compare station specifications, and follow commercial station development with SpaceNexus.

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