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👨‍🚀 Human Spaceflight

Space Station

Also known as: Orbital Station, Space Stations, Orbital Habitat

📘 Definition
A space station is a large spacecraft in low Earth orbit designed for long-duration habitation by rotating crews. Unlike crew capsules that visit orbit briefly, stations remain in orbit for years or decades, with crews exchanging via visiting vehicles. The International Space Station (ISS) — a collaboration of NASA, ESA, JAXA, CSA, and Roscosmos — is the largest structure ever built in space, spanning 109 metres with a pressurised volume of 916 m³ and a mass of 420 tonnes. China's Tiangong station represents the second currently operational space station. Both serve as microgravity research laboratories, technology testbeds, and platforms for EVAs. The ISS is expected to operate until approximately 2030, with commercial space stations planned to succeed it.
420 tonnes
ISS Mass
420 km, 51.6° inclination
ISS Orbit
Since 2 Nov 2000 (ISS)
Continuous Habitation
ISS + Tiangong
Current Stations

Understanding Space Station

History of Space Stations

StationNation(s)YearsKey Achievement
Salyut 1–7Soviet Union1971–1991First space stations; long-duration crew records
SkylabUnited States1973–1979First US station; solar observatory
MirSoviet Union/Russia1986–2001First permanently crewed station (3,644 days)
ISSInternational (5 agencies)1998–presentLargest structure in space; 25+ years continuous crew
TiangongChina2021–presentChina's permanent orbital laboratory

The ISS Transition

The ISS is expected to be deorbited around 2030–2031 via a controlled re-entry targeting the South Pacific. NASA's plan is to transition LEO operations to commercial space stations — companies like Axiom Space (modules already attached to ISS), Vast (Haven-1), and Orbital Reef (Blue Origin/Sierra Space) are developing successor stations. This marks a shift from government-owned infrastructure to commercially operated destinations where NASA is one of many customers.

Why Space Stations Matter

Space stations enable science impossible on Earth: growing protein crystals in microgravity for drug development, studying long-duration spaceflight effects on the human body (critical for Mars missions), testing life support systems, and observing Earth and space. The ISS has hosted over 3,000 scientific investigations from researchers in over 100 countries. Stations also serve as platforms for demonstrating technologies like robotic servicing, 3D printing in space, and EVA techniques for future lunar and Mars surface operations.

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Frequently Asked Questions

As of 2026, two fully operational crewed space stations orbit Earth: the International Space Station (ISS) and China's Tiangong. Several commercial space station modules are in development, with Axiom Space's first module already attached to the ISS.
NASA plans to deorbit the ISS around 2030–2031 using a dedicated SpaceX-built deorbit vehicle. The station will undergo a controlled re-entry targeting the South Pacific Ocean. It will be the largest human-made object ever deliberately deorbited, at approximately 420 tonnes.