NASA mission control ordered all four Crew-12 astronauts into their SpaceX Crew Dragon spacecraft today and directed them to don their spacesuits as a precautionary measure while Russian cosmonauts attempt to fix a worsening air leak in the Zvezda Service Module.

The four Crew-12 crew members — two US astronauts, a French astronaut, and a Russian cosmonaut — sheltered aboard the docked Crew Dragon as Roscosmos engineers worked to locate and repair the breach. The leak is located in the Service Module Transfer Tunnel — one of the oldest parts of the station, first launched in 1998.

The leak has been a persistent problem since it was first detected in 2019. In late 2025 it appeared to be resolved, but returned in May 2026. The rate accelerated from half a kilogram of air per day to a full kilogram per day on Monday — still manageable for the station's systems (which can be repressurised from nitrogen tanks), but enough to trigger NASA's evacuation protocols. A Russian crew member was attempting to fix the breach as the story developed.

The leak has previously delayed the Axiom Mission 4 launch indefinitely, and the incident highlights the fragile state of the aging ISS, which is scheduled to deorbit by 2030. Commercial successors including Axiom Station and Haven-1 are under development.