NASA faces a new issue at the International Space Station (ISS) because a persistent air leak has delayed a planned commercial astronaut mission launch. NASA delayed Axiom Mission 4 because the leak forced the agency to postpone the planned launch of four astronauts to the station.

NASA officially recognized the launch delay but provided limited information about the situation. Sources who know about the situation claim the leak has reached a severe stage. Since the ISS approaches its 30th year in orbit any minor problems are now handled with greater care.

An Old Problem Returns—In a New Way

The ISS has previously encountered problems with air loss. The Russian Zvezda service module has been responsible for a continuous small leak in the space station since 2019. Since its 2000 launch the Russian Zvezda service module now stands as one of the International Space Station’s oldest components. Experts identified the PrK transfer tunnel within the module as the source of the problem. The PrK transfer tunnel functions as a connector between Zvezda and the essential docking port for Russian Soyuz and Progress spacecraft.

Russian cosmonauts have made multiple attempts to repair the PrK throughout the history of the ISS. None of the repair attempts fully fixed the problem. The repair efforts resulted in a reduction of the air loss rate to only several pounds per day. The most effective approach has been to maintain the PrK hatch closed except during docking operations.

A short time ago the problem appeared to be fully fixed. Roscosmos declared that the latest repair work successfully sealed the PrK. NASA confirmed that leak rates inside the module had come to a halt according to their statement.

Despite repairs the ISS continued to experience overall pressure declines. That raised a big question: The station continued to lose air even though the module had been sealed.

The hatch seal leading into the PrK is now suspected by experts as the primary source of the leak. This theory suggests that air is gradually escaping through the seals into the PrK which maintains constant pressure. The module’s sensors do not detect any leaks which corresponds to the fact that air keeps escaping from other parts of the station.

NASA is now closely monitoring the situation. An industry insider informed Ars Technica about NASA leaders expressing worries regarding the situation. NASA postponed the Axiom-4 mission because of developing concerns. NASA announced that delaying Axiom Mission 4 will allow NASA and Roscosmos more time to assess the current situation and determine if extra troubleshooting steps are required.

NASA and Roscosmos have set June 18 as the new tentative launch date. The future schedule for the launch depends entirely on how the leaking situation progresses over the next few days.

There’s another layer to all this: Experts are examining whether the leak represents a more significant problem involving structural fatigue.

Engineers worry about high cycle fatigue since metals such as aluminum can undergo this process after enduring repeated stress throughout their lifespan. Picture bending a paperclip repeatedly until it breaks unexpectedly. Eventually, it snaps without warning. The nature of this failure manifests suddenly and poses significant danger.

The Aloha Airlines Flight 243 disaster in 1988 serves as a famous case of mid-air decompression due to metal fatigue. The aircraft’s fuselage tore apart because metal fatigue weakened its structure. The aircraft’s crew executed a safe landing yet this incident proved how fatigue can accumulate unseen until it results in failure.

NASA currently views structural cracking on the ISS as its primary concern. The risk matrix of NASA positions structural cracking on the ISS as highly probable and extremely severe. The severity of the ISS structural cracking issue has forced agency engineers to maintain an elevated state of alert.

NASA currently offers no further information beyond their standard statement. The agency has resisted organizing a press conference or issuing detailed information despite sustained inquiries from reporters including Ars Technica. The only official word remains: The astronauts aboard the International Space Station continue their routine operations without issues.

And they are. Life aboard the ISS continues. While the station appears stable, its systems are leaking air which causes concern about their ability to remain operational.