Five astronauts aboard the International Space Station (ISS) were ordered to shelter in a docked spacecraft and prepare for emergency evacuation on Friday, after a worsening air leak in the Russian segment of the orbital laboratory prompted NASA mission control to activate what it calls "safe-haven" procedures. The alert lasted roughly two hours before being stood down, and no crew members were ever in immediate danger.

At 9:04 am ET, NASA ordered four members of the Crew-12 mission — American astronauts Jessica Meir and Jack Hathaway, European Space Agency astronaut Sophie Adenot of France, and Russian cosmonaut Andrey Fedyaev — along with a fifth astronaut, Christopher Williams, to board the SpaceX Crew Dragon spacecraft "Freedom," which was docked to the station. The Dragon functions as a lifeboat: attached to the ISS but ready to detach and return to Earth at short notice. The five were instructed to don their spacesuits while NASA assessed the situation. Two Russian cosmonauts, station commander Sergey Kud-Sverchkov and flight engineer Sergei Mikayev, remained aboard and were not part of the safe-haven order; their designated escape vehicle is a separately docked Soyuz MS-28 spacecraft.

The leak is located in the transfer tunnel, known as PrK, connecting the main station to the Zvezda service module — a key structural component of the Russian segment at the rear of the ISS. Cracks in this area have persisted on and off for around six years. The situation escalated sharply this week, with air loss doubling from roughly one pound per day to two, according to a senior NASA official. The trigger for Friday's alert was not simply the leak itself, but a disagreement over how to fix it: Russian cosmonauts were planning to use a saw to cut into the area to access the crack, a method NASA disagreed with. Once Roscosmos agreed to pause the repair attempt, NASA reversed the safe-haven order and instructed the crew to return to normal operations aboard the station.

Roscosmos reported that two leaks had been identified, that one had already been sealed, and that neither posed a threat to the crew or the station's onboard systems. NASA spokesperson Bethany Stevens said the agency looked "forward to working with Roscosmos on a collaborative approach to address the leaks," underscoring that the two agencies are still negotiating both the cause and the remedy.

Safe-haven procedures are rare aboard the ISS, though debris-collision warnings and smaller pressure changes have triggered them before. In its 27-year history of continuous human habitation — operated by a US-Russian-led consortium including Canada, Japan, and 11 European countries — the station has never required a full evacuation. Retired Canadian astronaut Chris Hadfield, who commanded the ISS in 2012, offered perspective: some degree of air loss is a constant reality of life in space, he noted, but when the rate crosses certain thresholds, crews must be ready to act. Friday's incident resolved without that ultimate step being necessary.