As leaks on the space station worsen, there’s no clear plan to deal with them

NASA and the Russian space agency, Roscosmos, still have not solved a long-running and worsening problem with leaks on the International Space Station.

The microscopic structural cracks are located inside the small PrK module on the Russian segment of the space station, which lies between a Progress spacecraft airlock and the Zvezda module. After the leak rate doubled early this year during a two-week period, the Russians experimented with keeping the hatch leading to the PrK module closed intermittently and performed other investigations. But none of these measures taken during the spring worked.

"Following leak troubleshooting activities in April of 2024, Roscosmos has elected to keep the hatch between Zvezda and Progress closed when it is not needed for cargo operations," a NASA spokesperson told Ars. "Roscosmos continues to limit operations in the area and, when required for use, implements measures to minimize the risk to the International Space Station."

What are the real risks?

NASA officials have downplayed the severity of the leak risks publicly and in meetings with external stakeholders of the International Space Station. And they presently do not pose an existential risk to the space station. In a worst-case scenario of a structural failure, Russia could permanently close the hatch leading to the PrK module and rely on a separate docking port for Progress supply missions.

However, there appears to be rising concern in the ISS program at NASA's Johnson Space Center in Houston. The space agency often uses a 5x5 "risk matrix" to classify the likelihood and consequence of risks to spaceflight activities, and the Russian leaks are now classified as a "5" both in terms of high likelihood and high consequence. Their potential for "catastrophic failure" is discussed in meetings.

In responding to questions from Ars by email, NASA public relations officials declined to make program leaders available for an interview. The ISS program is currently managed by Dana Weigel, a former flight director. She recently replaced Joel Montalbano, who became deputy associate administrator for the agency’s Space Operations Mission Directorate at NASA Headquarters in Washington.

One source familiar with NASA's efforts to address the leaks confirmed to Ars that the internal concerns about the issue are serious. "We heard that basically the program office had a runaway fire on their hands and were working to solve it," this person said. "Joel and Dana are keeping a lid on this."