As leaks in the space station get worse, there is no clear plan to fix them

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

The microscopic structural cracks are located in the small PrK module of the Russian segment of the space station, which is located between an airlock for Progress spacecraft and the Zvezda Module. After the leak rate doubled in two weeks earlier this year, the Russians experimented with keeping the hatch to the PrK module temporarily closed and conducted further investigations. But none of the measures taken in the spring worked.

“Following the leak detection activities in April 2024, Roscosmos decided to close the hatch between Zvezda and Progress is closed when not needed for cargo operations,” a NASA spokesperson told Ars. “Roscosmos continues to restrict operations in the area and takes action as needed to minimize 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 International Space Station stakeholders. And at this time, they do not pose an existential risk to the space station. In the worst-case scenario of structural failure, Russia could permanently close the hatch to the PrK module and use a separate docking port for Progress resupply missions.

However, at NASA's Johnson Space Center in Houston, there appears to be growing concern about the ISS program. The space agency often uses a 5×5 risk matrix to classify the likelihood and consequences of risks to space activities, and the Russian leaks are now rated a “5” for both high probability and severe consequences. Their potential for “catastrophic failure” is being discussed in meetings.

In an emailed response to questions from Ars, NASA public relations officials declined to make program leaders available for an interview. The ISS program is currently led by Dana Weigel, a former flight director. She recently replaced Joel Montalbano, who became deputy director of the agency's Space Operations Mission Directorate at NASA headquarters in Washington.

A source familiar with NASA's efforts to fix the leaks confirmed to Ars that internal concerns about the problem were serious. “We heard that the program office basically had an out-of-control fire on its hands and was working to resolve it,” this person said. “Joel and Dana are keeping it under wraps.”

U.S. officials are likely keeping quiet about their concerns because they do not want to embarrass their Russian partners. Working relations have improved since the firing of the pugnacious head of Russia's space activities, Dmitry Rogozin, two years ago. The current leadership of Roscosmos maintains a friendly relationship with NASA despite high geopolitical tensions between Russia and the United States over the war in Ukraine.

The leaks are a sensitive issue. Because of Russia's war effort, funding for the country's civilian space program will remain flat or even decrease in the coming years. A dedicated core of Russian officials who care deeply about the International Space Station partnership are trying to “make do” with the funds they have to maintain the Soyuz and Progress spacecraft that carry crew and cargo to the space station, as well as the infrastructure on the station. But they are unable to make major new investments, so they have no choice but to patch things together as best they can.

Outdated infrastructure

At the same time, the space station is aging. Zvezda The module was launched on a Russian Proton rocket almost a quarter of a century ago, in July 2000. The cracking problem first appeared in 2019 and has continued to worsen since then. The cause is unknown.

“They have repaired several leaks, but there are more leaks,” the NASA spokesman said. “Roscosmos has not yet identified the root cause of the cracks, which makes it difficult to analyze or predict future crack formation and propagation.”

NASA and Russia have managed to maintain the space station partnership since the Russian invasion of Ukraine in February 2022. The large U.S. segment relies on the Russian segment to provide propulsion, maintain the station's altitude, and avoid debris. Since the invasion, the United States could have taken overt measures to counteract this, such as funding the development of its own propulsion module or increasing the budget for building new commercial space stations to maintain its presence in low Earth orbit.

Instead, senior NASA officials decided to stay the course and work with Russia as long as possible to maintain the fragile partnership and keep the old but venerable International Space Station running. It remains to be seen whether cracks – structural, diplomatic or otherwise – will derail that effort before the station's planned retirement date in 2030.