A persistent air leak in the Russian segment increased on Friday, prompting NASA to order personnel on board the International Space Station to seek shelter in their docked ship and get ready for a potential evacuation, according to several publications.
Order For Shelter
The SpaceX Crew Dragon “Freedom” capsule, which has been docked at the ISS since delivering the Crew-12 mission in February, was instructed to provide shelter to five of the seven crew members on board. As a precaution, the four Crew-12 astronauts—NASA astronauts Jessica Meir and Jack Hathaway, French astronaut Sophie Adenot of the European Space Agency, and Roscosmos cosmonaut Andrei Fedyaev—as well as NASA astronaut Chris Williams, put on their spacesuits. Williams stayed on the station following the early departure of Crew-11 in January, having been there since mid-2025.
Sergey Kud-Sverchkov and Sergei Mikaev, two Russian cosmonauts, stayed behind to fix the damaged module with mechanical patches and sealants.
Six Years In The Making Of A Leak
Microscopic structural fissures in the PrK transfer tunnel of the Zvezda service module on the Russian portion of the station are the source of the air leak, which was initially discovered in September 2019. A Progress cargo docking port is connected to the remainder of the module via the tunnel. Roscosmos has spent years trying to fix the cracks, but engineers haven’t been able to do so.
The leak reappeared in May when cosmonauts discovered a pressure drop while unloading a Progress cargo ship, after it had seemed to stabilize after repairs in the middle of 2025. The loss was estimated to be about one pound of air every day at the time. Reports state that it has since increased to about two pounds each day, mirroring a similar doubling noted in early 2024 that NASA’s ISS program manager described as manageable but alarming.
Conflict And Increased Danger
According to a 2024 inspector general report, NASA has internally categorized the leak at the highest level on its risk matrix, giving it a “5” for both chance and effect. The two organizations have long argued over how serious the situation is: Roscosmos argues that a “catastrophic failure” of the PrK module is implausible, while NASA has issued a warning. During a 2024 review, Bob Cabana, chair of the ISS Advisory Committee, stated, “The U.S. believes that it’s not safe, but we can’t prove to the Russians’ satisfaction that that’s the case, and the Russians believe that continued operations are safe, but they can’t prove to our satisfaction that they are.”