ISS Marks 25 Years of Continuous Human Presence — What to Know About the Orbital Outpost

International Space Station celebrates 25 years in orbit

On Nov. 2, 2000, Expedition 1 arrived at the newly assembled International Space Station (ISS), beginning an unbroken human presence in low Earth orbit that reaches its 25-year milestone in 2025. Since that arrival, the ISS has hosted continuous crews conducting microgravity research, Earth observation and international cooperation in space.

Overview

The ISS orbits roughly 260 miles (about 420 kilometers) above Earth and is operated through a partnership of major space agencies: NASA, Roscosmos, the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA) and the Canadian Space Agency (CSA). More than 280 people from 26 countries have visited the complex, including about 170 from the United States, according to NASA.

Size and facilities

The station stretches about 356 feet (108 meters) end-to-end — larger than a six-bedroom house — and includes six crew sleeping quarters, two bathrooms, a gym and the Cupola observation module that offers a wide, 360-degree view of Earth. The ISS can support multiple visiting vehicles, with docking ports that accommodate up to eight spacecraft simultaneously.

How it began

Although the first ISS module launched in 1998, continuous habitation began with the arrival of Expedition 1 on Nov. 2, 2000. That inaugural crew — William Shepherd (USA), Yuri Gidzenko (Russia) and Sergei Krikalev (Russia) — launched Oct. 31, 2000, and stayed aboard for nearly five months before returning to Earth on March 21, 2001.

Current crew and missions

As of the 25th anniversary, seven people live aboard the ISS as part of Expedition 73. Four of them arrived on the joint NASA–SpaceX Crew-11 mission: NASA astronauts Zena Cardman and Mike Fincke, JAXA astronaut Kimiya Yui and Roscosmos cosmonaut Oleg Platonov; that Dragon launched from Kennedy Space Center on Aug. 1. Additional crew members arrived aboard a Soyuz launch from Kazakhstan in April, joining the international complement conducting scientific investigations and station maintenance.

Notable achievements and records

• Longest single NASA stay: Frank Rubio spent 371 consecutive days on the ISS (2022–23), the longest single spaceflight for any NASA astronaut.
• Most cumulative days for an American: Retired astronaut Peggy Whitson has logged 695 total days in space across five missions.
• Spacewalk record for a woman: Suni Williams surpassed previous records in early 2025 with 62 hours and 6 minutes of accumulated extravehicular activity after her ninth career spacewalk.

Future and retirement plans

Despite its success, the ISS is aging and has experienced technical issues including air leaks. International partners are planning how to retire and deorbit the laboratory safely — with current planning discussions aiming for a controlled re-entry around 2030. Meanwhile, private companies are developing commercial successor habitats and research platforms to succeed the ISS era.

Why it matters: The ISS has demonstrated long-duration human spaceflight, enabled thousands of experiments only possible in microgravity, and proven international cooperation in orbit — paving the way for future exploration and commercial space stations.