The disagreement between NASA and Roscosmos regarding a air leak in the Russian segment of the International Space Station (ISS) continues. NASA is concerned that the leak could result in a "catastrophic failure" of a Russian module, while Roscosmos holds a different view on the severity of the issue.
The leak, located in a vestibule of the Zvezda service module called PrK, has been present for several years. Crews have managed it by sealing off PrK from the rest of the station when not in use. NASA and Roscosmos engineers disagree on the cause and severity of the leak, despite ongoing investigations.
While Roscosmos believes the cracks causing the leak are due to "high cyclic fatigue" from micro-vibrations, NASA attributes it to a combination of pressure, mechanical stress, residual stress, material properties, and environmental exposure.
A report by NASA's Office of Inspector General (OIG) focused on internal and external welds as a potential source of the leaks, which have not been observed elsewhere on the station. The leak rate has fluctuated, reaching a peak of 1.7 kilograms of air per day earlier this year, but recent repairs have reduced it by a third.
Despite the repairs, the leak remains a concern for both agencies and station crews. Astronaut Michael Barratt, who returned from the Crew-8 mission in October, reported that NASA takes precautions when the hatch to PrK is open, including closing the hatch between the US and Russian segments.
While Roscosmos believes continued operations are safe, NASA holds reservations about the structural integrity of PrK and the potential for a catastrophic failure. Both agencies are working to reach a common understanding of the issue and are seeking input from outside experts.
The ISS Advisory Committee, which comprises representatives from both NASA and Roscosmos, recommends further investigation into the structural integrity of PrK. An independent team has been assembled by NASA to assess the leaks.
The leak highlights the aging nature of the ISS and the need for ongoing maintenance and repairs. While the situation is being monitored closely, both agencies remain committed to ensuring the safety and continued operation of the ISS.