NASA has announced that four astronauts currently aboard the International Space Station (ISS) will return to Earth earlier than planned due to a medical issue involving one crew member. The decision was made as a precautionary step, even though the affected astronaut remains stable.

The astronauts are part of SpaceX’s Crew-11 mission, which launched in August 2025. NASA confirmed on January 8, 2026, that the crew will leave the space station ahead of schedule. This marks the first evacuation of astronauts from the ISS due to a medical reason in the station’s 25-year history.

Officials stressed that there is no emergency situation and that an urgent de-orbit was not required. According to NASA, the early return is meant to allow doctors on Earth to conduct full medical diagnostics that are not possible in the microgravity environment of space.

The four astronauts include NASA’s Mike Fincke and Zena Cardman, Kimiya Yui of the Japan Aerospace Exploration Agency (JAXA), and Oleg Platonov from Russia’s space agency Roscosmos. They travelled to the ISS aboard a Crew Dragon spacecraft launched from Kennedy Space Centre on August 2, 2025.

Originally, the Crew-11 mission was scheduled to last around six months, with the return planned for March 2026. However, NASA officials decided to bring the crew back earlier to reduce potential medical risks.

NASA Administrator Jared Isaacman, speaking during a Thursday press conference, said the return plan fits into upcoming mission schedules. He stated that the crew’s return “aligns with upcoming Crew-12 preparations” and added that it could lead to Crew-12 being launched earlier than expected, possibly moving the launch from mid-February.

NASA’s Chief Health and Medical Officer, Dr. James Polk, explained that the decision was taken due to diagnostic limitations in space. He highlighted the “lingering risk” involved when full medical evaluations cannot be performed on orbit. Dr. Polk said NASA chose to act cautiously, even though the astronaut’s condition remains stable. He also confirmed that neither the medical issue nor the identity of the affected astronaut would be disclosed to protect privacy.

Earlier this week, a planned spacewalk involving astronauts Mike Fincke and Zena Cardman was postponed. NASA clarified that the delay was unrelated to the medical situation or preparations for the crew’s return.

Meet the Astronauts

The four astronauts set to return early from the ISS are:

• Zena Cardman (Commander, NASA) – A first-time space traveller leading the international crew.
• Mike Fincke (NASA) – A veteran astronaut on his fourth mission to the ISS, with extensive experience in long-duration spaceflights.
• Kimiya Yui (JAXA) – A Japanese astronaut flying his second space mission.
• Oleg Platonov (Roscosmos) – A Russian cosmonaut on his debut spaceflight.

Since docking with the ISS in August 2025, Crew-11 has supported continuous station operations, continuing the international collaboration that has kept the space station active since the year 2000.

NASA said the spacecraft is expected to splash down “in the coming days,” depending on weather conditions. After their return, one U.S. astronaut will remain aboard the ISS along with Russian crew members to ensure operational continuity.

NASA emphasised that there is no cause for alarm. Astronauts are trained extensively for such situations, and contingency plans are always in place. Officials are also reviewing options for Crew-12 to ensure there are no major operational gaps.

The event highlights both the progress in space medicine and the ongoing challenges of providing advanced healthcare in microgravity. While basic treatment is possible on orbit, more complex cases still require a return to Earth.