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Boeing International Space Station (ISS)

Boeing · Space Station / Crewed Microgravity Research / Technology Demonstration · International (USA / Russia / Europe / Japan / Canada) · Modern (1992–2009)

Boeing International Space Station (ISS) — Space Station / Crewed Microgravity Research / Technology Demonstration
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The International Space Station (ISS) is a modular orbital platform in low Earth orbit, jointly developed and operated by five space agencies: NASA (United States), Roscosmos (Russia), JAXA (Japan), ESA (European Space Agency), and CSA (Canadian Space Agency). It is the largest crewed space station ever built, and has been continuously occupied by international crews since 2 November 2000 — over 25 years of unbroken human presence in space, the longest sustained human spaceflight in history. As of 2026 the station measures 109 m × 73 m (358 ft × 240 ft), masses 420,000 kg, orbits at 400-420 km altitude with a 90-minute orbital period (15.5 orbits per day), and accommodates 7-13 crew during ISS Expedition operations.

The programme originated as Space Station Freedom, a 1984 NASA / Reagan-administration proposal, and was expanded to include Russian participation in 1993 after the Cold War's end. On-orbit assembly began in 1998. Initial buildup relied on the Space Shuttle together with Russian Proton and Soyuz launches, with later flights flown by a wider mix of international partners. The first module — the Russian-built Zarya — launched in November 1998. It was joined by U.S.-built Unity / Node 1 (December 1998), Russian Zvezda (July 2000), Destiny / U.S. Laboratory (2001), the Quest Joint Airlock (2001), Pirs (Russian, 2001 — retired 2021), Harmony / Node 2 (2007), Columbus (ESA, 2008), Kibo (JAXA, 2008), Tranquility / Node 3 (2010), Cupola (2010), Permanent Multipurpose Module / Leonardo (2011), the Bigelow Expandable Activity Module (2016), and the truss segments and solar arrays. Total assembly took roughly 36 Space Shuttle missions plus many Russian and international launches.

On-orbit research spans human physiology in microgravity (long-duration adaptation, bone and muscle loss, cardiovascular changes), materials science (microgravity crystal growth, advanced manufacturing), Earth observation (atmospheric and climate research, disaster monitoring), space medicine (cancer and pharmaceutical research), and basic physics (cold-atom experiments, dark-matter searches via the AMS-02 instrument). Output to date exceeds 4,000 peer-reviewed publications based on ISS experiments. Roughly 270 individual astronauts and cosmonauts from 23 nations have flown to the station through 2026 — the largest international crewed spaceflight programme in history.

The programme has stayed operational through serial challenges: emergency operations including evacuations, equipment failures and ammonia leaks; political tensions, especially U.S. / Russia friction following the 2014 Crimea invasion and 2022 Ukraine invasion, which have not broken the partnership; and continually contested NASA and international-partner funding. Participants have committed to operations through 2030, with a controlled de-orbit planned for around 2031. Follow-on planning centres on commercial low-Earth-orbit stations — Axiom Space, Vast, Orbital Reef and Starlab — intended to maintain crewed LEO presence post-ISS. The ISS stands as one of the foremost achievements of international scientific cooperation and of space engineering.

For Kids — a shorter, friendlier version

The International Space Station (ISS) is a giant laboratory in space. It orbits about 250 miles above Earth, going around the planet every 90 minutes — so the astronauts inside see a sunrise and sunset every 45 minutes.

The ISS is huge — about the size of a football field. It weighs almost 1 million pounds. Inside, the living and working space is about as big as a 6-bedroom house. The ISS has been continuously occupied by astronauts since November 2000 — over 25 years of nonstop human presence in space.

The ISS was built piece by piece in space. NASA, Russia, Europe, Japan, and Canada all contributed parts. The first piece was launched in 1998. The Space Shuttle and Russian Soyuz rockets carried modules and astronauts into orbit. By 2011, the basic ISS was complete.

Six or seven astronauts usually live on the ISS at any time. They stay 6 months and then return home. While in space, they do science experiments — growing crystals, watching how fluids behave without gravity, studying how the human body changes in space. Over 3,000 experiments have been done on the ISS so far.

The ISS will be retired around 2030. NASA is helping private companies build smaller commercial space stations to replace it. The current plan: deorbit the ISS into the Pacific Ocean in early 2031.

Fun Facts

  • The ISS is about the size of a football field — and weighs nearly 1 million pounds.
  • Astronauts see 16 sunrises and 16 sunsets every day from the ISS.
  • The ISS has been continuously occupied since November 2000 — over 25 years of nonstop humans in space.
  • Six or seven astronauts usually live on the ISS at a time, for 6-month stays.
  • Five space agencies built the ISS: NASA (USA), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada).
  • Over 3,000 science experiments have been done on the ISS.
  • The ISS will be deorbited into the Pacific Ocean around 2031.

Kids’ Questions

How fast does the ISS move?

The ISS travels about 17,500 miles per hour — that's about 23 times faster than a passenger jet. It has to go this fast to stay in orbit. If it slowed down, gravity would pull it back to Earth. The ISS goes all the way around the planet every 90 minutes. From the ISS, astronauts can see almost the whole world every day. They often photograph cities, oceans, and weather systems passing below them.

What happens when an astronaut gets sick on the ISS?

Each ISS crew has trained medical equipment and supplies for handling small problems — colds, cuts, headaches, etc. One crew member is specially trained as the "Crew Medical Officer" to handle bigger emergencies. For serious problems, the astronauts can call doctors on Earth for advice. If something really bad happened, astronauts could return to Earth in a Soyuz or Crew Dragon capsule (which always stays docked to the ISS as a lifeboat) — landing within about 4 hours. Luckily, no astronaut has ever needed emergency evacuation from the ISS so far.

Variants

ISS modules (NASA / U.S.)
U.S. Operating Segment modules: Unity / Node 1 (1998), Destiny / U.S. Lab (2001), Quest Joint Airlock (2001), Harmony / Node 2 (2007), Tranquility / Node 3 (2010), Cupola observation module (2010), Permanent Multipurpose Module / Leonardo (2011, originally Italian-built), and the Bigelow Expandable Activity Module (BEAM, 2016).
ISS modules (Russia / Roscosmos)
Russian Operating Segment modules: Zarya / FGB (1998, U.S.-funded but Russian-built), Zvezda Service Module (2000), Pirs Docking Compartment (2001-2021), Poisk Mini-Research Module 2 (2009), Rassvet Mini-Research Module 1 (2010), Nauka Multipurpose Laboratory Module (2021), and Prichal Nodal Module (2021).
ISS modules (Japan / JAXA / ESA / Canada)
International partner modules: Columbus (ESA, 2008) and Kibo (JAXA Japanese Experiment Module, 2008 — pressurised module, exposed facility, and experiment logistics module). The Canadian Space Agency contributed Canadarm2 (mobile robotic-arm system, 2001) and Dextre (specialised dexterous manipulator, 2008).
Truss / Solar Arrays / Power Systems
Integrated Truss Structure (S0 / P1 / S1 / P3 / S3 / P4 / S4 / P5 / S5 / P6 / S6) forms the backbone connecting modules and supporting solar arrays and radiators. Eight large solar-array wings deliver 75-90 kW of electrical power; ISS Roll-Out Solar Arrays (iROSA) began augmenting and replacing them in 2021.
Visiting Vehicles
Crew transport: Soyuz (Russian, since 2000), Crew Dragon (U.S./SpaceX, since 2020), and Boeing Starliner (initial flight 2024). Cargo transport: Cygnus (U.S./Northrop Grumman), Cargo Dragon (U.S./SpaceX), Progress (Russian), HTV / HTV-X (Japanese), and ATV (European, retired 2014).

Notable Operators

NASA / U.S. Operating Segment
Principal U.S. operator. NASA's ISS Program runs the U.S. Operating Segment modules, U.S. crew transport (Crew Dragon, Boeing Starliner), and U.S. research operations. Programme cost to the U.S. is around $150 billion through 2025 — the largest U.S. spaceflight programme ever.
Roscosmos / Russian Operating Segment
Russian space agency. Operates the Russian modules (Zarya, Zvezda, Nauka, Prichal and others), Soyuz crew transport, and Russian research operations. The Russian segment is critical to station operations — propulsion and reboost capability come principally from its modules.
JAXA / ESA / CSA (international partners)
JAXA operates the Kibo Japanese Experiment Module and HTV / HTV-X cargo transport. ESA operates the Columbus laboratory and contributed the ATV (retired 2014). CSA operates Canadarm2, Dextre, and the Mobile Servicing System (MBS).
ISS expedition crews
Roughly 270 individual astronauts and cosmonauts from 23 nations through 2026 across more than 70 ISS Expeditions. Frank Rubio (NASA) holds the U.S. spaceflight duration record at 371 days (Soyuz MS-22 / -23, 2022-2023). Several Russian cosmonauts have flown 6+ ISS missions. The longest single ISS expedition is around 371 days.

Frequently Asked Questions

How big is the ISS?

External dimensions are 109 m × 73 m (358 ft × 240 ft) — about the size of an American football field. Total mass is around 420,000 kg (925,000 lb), and pressurised volume is 916 m³ (32,300 cu ft), comparable to a Boeing 747 cabin. The ISS is roughly 4 times larger than the previous-largest space station (Russian Mir, decommissioned 2001) and around 200 times larger than the original Soviet Salyut-1 (1971). It is large enough to be visible from Earth as a bright moving point of light during overhead passes — typically appearing as the brightest 'star' in the night sky.

How long has the ISS been occupied?

Continuously since 2 November 2000, when ISS Expedition 1 (William Shepherd, Yuri Gidzenko, Sergei Krikalev) docked. As of 2026 that is over 25 years of continuous human presence in space — the longest sustained crewed-spaceflight period in history, by a wide margin. The previous record-holder, the Russian Mir station (1986-2001), achieved continuous occupation only between September 1989 and August 1999, with brief gaps.

How does the ISS compare to Mir?

The ISS is far larger and more international than Mir. Mir (1986-2001): Soviet / Russian, 124,000 kg, 33 × 31 m, single-nation operation with international visitors, continuously occupied 1989-1999. ISS (1998-present): five-agency international cooperation, 420,000 kg (3.4× larger), 109 × 73 m (3.3× larger), continuously occupied since November 2000. The ISS has hosted around 270 individual crew from 23 nations, against Mir's ~125 individual crew from ~12 nations.

How is the ISS resupplied?

By cargo spacecraft from multiple partners. SpaceX Cargo Dragon (NASA Commercial Resupply Services, ~30 missions through 2025) performs autonomous rendezvous, is berthed via Canadarm2, and returns to Earth with experiment results. Northrop Grumman Cygnus (NASA Commercial Resupply Services, ~22 missions) is expendable and burns up after de-orbiting. Russian Progress (80+ missions since 2000) is an autonomous Soyuz-derived freighter that performs automated docking at the Russian segment. Japanese HTV / HTV-X (~10 missions through 2024) carries the largest cargo load and uses robotic-arm berth-then-deploy operations. European ATV flew 5 missions from 2008-2015 with autonomous rendezvous and Russian-segment docking before the programme ended.

Who travels to the ISS?

Crew rotation typically includes 7 expedition crew (4 NASA / international + 3 Roscosmos), with brief spikes to 10-13 during handovers. Crew transport since 2000 has used Soyuz (Russian, 70+ flights), Crew Dragon (NASA Commercial Crew, since May 2020, 13+ flights), and Boeing Starliner (limited flights since 2024). All ISS crew train at NASA Johnson Space Center, Yuri Gagarin Cosmonaut Training Center (Russia), JAXA Tsukuba Space Center (Japan), and the European Astronaut Centre (Germany). Around 270 individual astronauts and cosmonauts have flown to the station through 2026, from 23 nations including the U.S., Russia, Japan, Canada, France, Germany, Italy, the UK, the Netherlands, Belgium, Brazil, Israel, the UAE, South Korea, Saudi Arabia, Turkey, Sweden, Spain, Poland, Hungary, Czech Republic, Bulgaria, and others.

What happens after ISS retires?

Several commercial low-Earth-orbit stations are planned to follow. NASA selected three commercial development partners in December 2021: Axiom Space (planning to attach commercial modules to the ISS first, then detach to form an independent station), Orbital Reef (Blue Origin / Sierra Space / Boeing partnership), and Starlab (Voyager Space / Lockheed Martin / Airbus partnership). Russia has signalled plans for a Russian Orbital Service Station (ROSS) to replace its ISS contributions. The ISS programme is committed to operations through 2030, with controlled de-orbit and decommissioning targeted for around 2031. The follow-on stations are intended to maintain continuous LEO crewed-spaceflight capability after the ISS.

Sources

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