ISS Is Leaking. NASA Thinks That Could Be 'Catastrophic'

With astronauts stranded on the International Space Station for months, you may have forgotten all about the aging space station's persistent air leaks. Well, they're still there and, according to NASA, they are now the ISS' most pressing issue, threatening the safety of the astronauts on board, CNN reports. The US space agency "has expressed concerns about the structural integrity" of the PrK vestibule that connects a docking port to the Russian-controlled Zvezda module "and the possibility of a catastrophic failure," Bob Cabana, chair of NASA's ISS Advisory Committee, said during a meeting this week. But the Russian space agency Roscosmos "does not believe catastrophic disintegration of the PrK is realistic."

Leaks were first discovered in PrK in 2019. In February, NASA gave the issue the highest possible risk level, noting the rate of air escaping each day had doubled from one pound to more than two, per Gizmodo. The rate peaked at 3.7 pounds per day in April, but was reduced "by roughly a third" with repairs, per Space.com. A September report from NASA's Office of Inspector General notes Roscosmos "is confident they will be able to monitor and close the hatch to the Service Module prior to the leak rate reaching an untenable level." "The Russians believe that continued operations are safe—but they can't prove that to our satisfaction," Cabana said, per CNN. "And the US believes that it's not safe, but we can't prove that to the Russian satisfaction."

At the same time, the two space agencies can't agree on the cause of the leaks. NASA blames cracks, too small to be seen, caused by pressure and mechanical stress, residual stress, material properties, and environmental exposure, while Roscosmos blames high cyclic fatigue from micro vibrations, per CNN. The US is now calling for independent experts to evaluate the problem. In the meantime, the leaking segment is sealed off from the rest of ISS when not in use and when it is opened, the hatch separating the US and Russian areas is closed, CNN reports. ISS can continue operating if the leaking segment is closed permanently, but that will mean "one less cargo delivery port," per the OIG report. (More International Space Station stories.)