NASA orders five crew members into SpaceX lifeboat as Russian cosmonauts repair air leaks on International Space Station

On Friday morning, NASA directed four SpaceX Crew-12 astronauts (Jessica Meir, Jack Hathaway, Sophie Adenot, and Andrey Fedyaev) and NASA astronaut Chris Williams into the Crew Dragon Freedom spacecraft around 9 am EST (14:00 UTC) while Russian cosmonauts Sergey Kud-Sverchkov and Sergei Mikayev worked on air leaks in the Zvezda Service Module's transfer tunnel (PrK) on the opposite end of the station, approximately 200 feet away.

The leak affects a transfer tunnel that connects to a docking port for Progress resupply and refueling freighters. Engineers believe microscopic cracks in the module's structure cause the leaks. For more than half a decade, Roscosmos and NASA engineers have tracked the leak rate; after a few months of pressure stability earlier this year, Roscosmos confirmed in May that air leaks had returned.

After about 90 minutes, Roscosmos elected to pause structural repair efforts and perform measurements only, allowing the crew to reopen hatches and reenter the station. Roscosmos identified two potential leak sites during pressurization of the transfer chamber, sealing one with a two-component sealant compound called Germetall-1; the second site, located on the conical section, was in preparation for sealing. Roscosmos stated there is 'no threat to crew safety or onboard systems.'