NASA spokesperson Bethany Stevens disclosed early on June 6 Beijing time that a new leak had been found in the Zvezda service module’s transfer tunnel (PrK compartment), which is managed by Russia on the International Space Station. Russia then launched a larger-scale repair operation on June 5. As a precaution, NASA ordered the four members of the SpaceX Crew-12 mission and astronaut Chris Williams to take shelter in the Dragon spacecraft; the two Russian astronauts used the docked Soyuz MS-28 spacecraft as their backup escape route. Roscosmos reported two leaks in total, one of which was quickly sealed with Germetal-1 two-component sealant. About two hours later, Russia suspended repairs to evaluate more measurement data, and NASA then lifted the evasion procedure.
Behind this incident is a persistent leak problem that has plagued the ISS for years: the first report of “air leak rate exceeding standard” was in 2019. Since then, the leak has continued and has never been permanently fixed. The latest situation shows that the leakage in the relevant module has doubled compared with the previous period. The contradiction lies here too — according to a senior anonymous NASA official, Russian astronauts used a saw to cut through the cabin wall to reach the leak during repairs. NASA disagreed with this approach and triggered the shelter procedure. NASA plans to keep the space station operational until 2030, when commercial space stations will take over. However, Russia has yet to commit to continuing its responsibility for its modules after 2028. This week, NASA also withdrew a plan proposed in March to build a transitional core module funded by the government, returning to a private-sector-led approach.