Safe-haven protocol activated

Mission control instructed five astronauts to enter their docked SpaceX Crew Dragon capsule at 9:04 a.m. ET (1304 GMT) and don their spacesuits. The group included the four members of the Crew-12 mission—NASA astronauts Jessica Meir and Jack Hathaway, European Space Agency astronaut Sophie Adenot, and Roscosmos cosmonaut Andrey Fedyaev—alongside a fifth U.S. astronaut, Christopher Williams.

The emergency "safe-haven" order was lifted roughly two hours later after NASA and Russia’s space agency, Roscosmos, evaluated the leak and determined conditions had stabilised.

Heightened leak rate prompts alarm

The two space agencies have been investigating a persistent leak in the Zvezda service module for months. However, the protocol was triggered after the leak rate recently doubled, jumping from about one pound of air per day to two pounds.

The shelter order was also prompted by a disagreement over troubleshooting methods. While Russian cosmonauts attempted to access and investigate a suspected crack using specific equipment, U.S. officials reportedly disagreed with the approach, leading Houston mission control to issue the precautionary order.

Current station status

The ISS currently hosts seven crew members distributed across two missions. While five took shelter in the Crew Dragon capsule, the remaining two Russian cosmonauts, Sergey Kud-Sverchkov and Sergei Mikayev, were also on board.

Emergency safe-haven procedures are rarely activated on the ISS, typically reserved for severe space debris threats or system anomalies. A full evacuation of the station has never occurred in its 27-year history.