ISS Celebrates 25 Years of Continuous Human Presence

A quarter-century of life in orbit highlights achievements, challenges, and the future of space habitation.

This weekend marks a historic milestone for the International Space Station (ISS), which has maintained uninterrupted human presence in orbit for 25 years. Since November 2, 2000, nearly 300 individuals — mostly astronauts, but also tourists and creatives — have visited the station. The achievement underscores the station’s role as a hub for international cooperation, scientific research, and technological advancement. With only five years left in its operational timeline, NASA is preparing for a transition to privately operated orbital platforms.

Early Missions and International Collaboration

The first long-term crew, consisting of NASA’s Bill Shepherd and Russia’s Sergei Krikalev and Yuri Gidzenko, launched from Kazakhstan on October 31, 2000. Upon arrival, they transformed the dark, humid station into a livable environment during their five-month stay. Shepherd, now retired, continues to advise on station matters alongside Krikalev, who holds a senior position in Russia’s space agency. Despite strained national relations, cooperation between space agencies remains strong and productive.

Over the years, the ISS has welcomed 290 visitors from 26 countries, with seven currently aboard representing the U.S., Russia, and Japan. The first self-funded tourist, Dennis Tito, flew in 2001, paving the way for future private missions. Russia continued to host paying guests, including a film crew in 2021, while NASA now supports short-term private visits. Recent guests included astronauts from India, Poland, and Hungary, accompanied by Peggy Whitson, the station’s first female commander.

Life, Risks, and Research in Orbit

Living on the ISS has evolved significantly since its early days. Modern amenities include internet phones, a panoramic cupola for Earth views, and experimental greenhouses producing peppers and flowers. Though astronauts still rely on sponge baths and discard used clothing, comforts have improved. Musical performances, such as Chris Hadfield’s rendition of “Space Oddity,” have added a human touch to life in space.

Operations aboard the station are far from routine, with incidents ranging from air leaks to space debris threats. A spacewalker once nearly drowned, and a docking mishap caused the station to spin uncontrollably. Despite these challenges, the ISS has exceeded its original design life, a fact that surprises even its earliest crew members. Scientific research continues, with thousands of experiments conducted, including medical studies and long-duration missions.

NASA’s twins study, involving Scott and Mark Kelly, provided insights into the effects of extended space travel. Scott spent a year in orbit while Mark remained on Earth, allowing for direct physiological comparisons. Mark also contributed to astronomy by installing a cosmic particle detector during a shuttle mission. Further upgrades to the station’s scientific equipment are scheduled for next year.

Transition to Commercial Stations

As the ISS approaches retirement in 2031, NASA has contracted SpaceX to manage its deorbiting. A specialized capsule will guide the station to a controlled reentry over the Pacific Ocean. Before that, Axiom Space will detach its module, which will serve as the foundation for a new commercial station. Other companies are developing their own orbital platforms to continue human activity in space.

NASA aims to avoid a gap between the ISS and its successors, ensuring continuous U.S. presence in low Earth orbit. The transition reflects a broader shift toward privatization and expanded access to space. Future stations are expected to accommodate a wider range of participants, from researchers to tourists. The legacy of the ISS will inform the design and operation of these next-generation habitats.