A Russian astronaut today told mission control that he thinks he has located another leak in the Zvezda module of ISS.

Roscosmos cosmonaut Pyotr Dubrov detected a possible air leak spot in the intermediate chamber of the Zvezda module aboard the International Space Station (ISS), the cosmonaut told the Flight Control Center during a communications session on Monday.

The Russian cosmonaut said he had traced the possible spot of the continued air leak while inspecting the Zvezda module’s intermediate chamber at the weekend. “I began preparing a perimeter for laying a cord today. I detected a suspicious spot and started to examine it,” the cosmonaut said, replying to a question about the work in the intermediate compartment in a live broadcast by NASA.

As the Russian cosmonaut said, he made a photo of the detected spot using a microscope with magnifying lens. He did not make video footage of the works, he said. [emphasis mine]

The highlighted words are significant. Up until now all leaks that the Russians have identified have been in Zvezda’s aft section, the part where the docking port is located. That pattern suggested that the many dockings over the module’s two decade-plus lifespan could have led to stress fractures in that module.

That they might have now found an air leak in intermediate section of the module suggests that the age-caused stress fractures are occurring in a more widespread manner. This is very concerning.

On a positive note, when the astronauts sealed the earlier leaks in the aft module, the loss of air dropped significantly. If the leak stops entirely when they seal this leak, we will have some confidence that the problem is under some control, for the time being.