NASA and Roscosmos Clash Over ISS Air Leak Concerns and Cause

NASA and Russia’s Roscosmos are at odds over the source and severity of a persistent air leak in the Russian segment of the International Space Station (ISS), an issue NASA fears could result in “catastrophic failure” in part of the Zvezda module. The leak has prompted NASA and Roscosmos to hold a series of meetings to try and understand the issue’s root cause and its potential impact on station operations.

Longstanding Leak in the Zvezda Service Module

The air leak has been traced to a vestibule in the Zvezda service module, known as the PrK, which serves as a docking port for Russia’s Progress cargo spacecraft. First detected in 2019, the leak has since fluctuated, with recent measurements showing its highest rate to date. When not in use, the PrK area is typically sealed off from the rest of the station to limit air loss.

The disagreement centres around the cause of the issue. According to NASA, the leaks likely stem from several combined factors, including pressure fluctuations, mechanical stress, and exposure to environmental conditions. Roscosmos, on the other hand, attributes the problem mainly to “high cyclic fatigue” caused by micro-vibrations within the structure.

Addressing Structural Concerns

NASA’s Office of Inspector General (OIG) recently released a report suggesting the leaks could be linked to internal and external welds in the PrK module. In response, both agencies have focused repair efforts on those areas. While recent repair efforts reduced the leak rate by about a third, the issue continues to be a concern.

NASA officials, including astronaut Michael Barratt, reported that they take extra precautions when accessing the PrK area by closing hatches between the U.S. and Russian segments during these periods. He noted the situation was “not comfortable” but stressed that it was a practical measure to ensure safety.

Disagreement on Severity and Safety Measures

During a recent meeting, the NASA ISS Advisory Committee, chaired by former astronaut Bob Cabana, discussed the split perspective between NASA and Roscosmos on how severe the PrK module’s structural problem could be. While Roscosmos engineers remain confident that ongoing operations in the area are safe, NASA has raised concerns about PrK’s structural integrity and the possibility of a catastrophic failure if the issue is left unaddressed.

Cabana highlighted this tension, noting, “The Russians believe that continued operations are safe, but they can’t prove to our satisfaction that they are. The U.S. believes that it’s not safe, but we can’t prove to the Russians’ satisfaction that that’s the case.” The committee recommended that NASA and Roscosmos bring in independent experts from academia and industry to reach a clearer consensus on the PrK’s structural condition.

Path Forward: A Joint Effort

NASA has assembled an independent team to assess the leak and potential solutions. Cabana expressed optimism that bringing in external expertise could lead to a resolution that satisfies both NASA’s and Roscosmos’s concerns. He also noted that some structural wear and tear on the ISS is expected after years in orbit.

Despite the ongoing leak issue, both agencies remain committed to maintaining station safety and continuing cooperation. The PrK module’s situation underscores the ISS’s ageing infrastructure and the challenges faced by international partners in sustaining the decades-old station.