Astronauts aboard the International Space Station (ISS) have been instructed to take precautionary shelter inside a docked spacecraft after air leaks were detected in the Russian segment of the orbiting laboratory.
The issue was identified in the Zvezda service module’s transfer tunnel, prompting Russian cosmonauts to carry out urgent repair operations to prevent further pressure loss.
As a safety measure, five of the seven cosmonauts working in the Russian segment temporarily moved into the SpaceX Crew Dragon spacecraft, “Freedom,” which is currently docked at the station. The remaining two crew members stayed behind to handle repair efforts.
According to Russian state media reports, one of the two detected leaks has already been sealed, while work continues on the second leak located in the conical section of the transfer chamber. Authorities say the remaining leak does not pose an immediate danger to the crew.
The Russian space agency, Roscosmos, said the leaks were discovered during a routine pressurisation test of the module’s transfer tunnel. It noted that the structure has experienced small cracks for years, which had previously been managed through temporary repairs.
However, a fresh pressure drop recorded last month prompted a more extensive repair operation.
NASA confirmed the situation, explaining that the Zvezda module’s transfer tunnel—known as PrK—has long experienced structural cracks that have been closely monitored in collaboration with Roscosmos.
A NASA spokesperson said both agencies have been working to determine the root cause of the issue while carrying out operational mitigation and periodic repair efforts.
Following the latest leak detection, Roscosmos initiated a more comprehensive repair operation on Friday, June 5.
NASA added that, as a precaution, all NASA crew members aboard the station were placed on a heightened safety posture inside the docked Dragon spacecraft during the ongoing repairs.
Both space agencies say they are continuing joint efforts, alongside international partners, to find a long-term solution to ensure the continued safety and stability of the ISS.