NASA postponed the planned launch of Axiom Mission 4 after discovering a new air leak on the International Space Station (ISS). NASA and Roscosmos have delayed the commercial launch mission to transport four astronauts to the ISS as they analyze the ongoing situation further. The agency acknowledged the launch delay but provided little information about the specifics. Multiple reports indicate the leak represents a significant problem because many ISS components are now 30 years old while still in space.

The station has encountered air leaks before this incident. Since 2019 the ISS has experienced a gradual decrease in cabin pressure. The Russian Zvezda service module’s transfer tunnel stands as the main source of the leak within the ISS. The PrK section creates a connection between the Zvezda module and the docking port which Soyuz capsules and Progress supply vehicles often use. Russian cosmonauts have implemented different repair methods to fix the small cracks in this area over several years. The repair attempts reduced the air loss rate to about two pounds daily but failed to stop it completely. The most efficient solution has been to maintain a sealed hatch to the PrK module and only open it when docking is required.

Roscosmos revealed that its repair efforts on the PrK module met their objective to completely seal the section while NASA confirmed these results by reporting that leakage in the specific module had ceased. This development appeared to represent a substantial advancement at first. However, things quickly became confusing. After repairs sealed the PrK module leak the ISS air pressure kept dropping. The source of the ongoing pressure loss remained unknown despite two sources reporting the station continued to lose pressure.

Experts currently believe that the hatch seals that connect to the PrK module might be causing the problem. The PrK interior may no longer have leaks but the hatch seals could permit air from the rest of the station to infiltrate the PrK. The PrK module maintains stable pressure simultaneously with overall ISS pressure continuing to decrease. NASA has adopted a careful strategy because this problematic issue remains difficult to identify. According to a senior industry source who spoke with Ars Technica NASA leadership feels “worried” about the current situation which may affect the structural integrity of the ISS.

NASA postponed the planned Thursday launch of Axiom Mission 4 due to current circumstances. In a brief statement, the agency said: The delay of Axiom Mission 4 enables NASA and Roscosmos to assess the situation and decide if further troubleshooting measures are required.

There’s another layer of concern: The continuous leaks present evidence of high cycle fatigue in the structure. Metals such as aluminum which form a major component of the ISS structure develop this condition when exposed to repeated stress throughout their lifetime. A metal clothes hanger will break when bent repeatedly back and forth. This same principle applies to spacecraft. Aircraft suffering from fatigue-induced cracking can experience devastating failures as evidenced by the 1988 Aloha Airlines accident when metal fatigue caused the fuselage to tear apart during flight.

NASA evaluates structural cracking on the ISS as its top priority risk within its 5-by-5 internal risk matrix which measures both threat likelihood and severity levels. While the crew currently faces no immediate danger their situation presents concerning future risks.

NASA has yet to offer new information and remains without a scheduled press conference to discuss the matter further. In response to media inquiries, the agency has reiterated a single point: The International Space Station crew continues normal operations safely.

Still, the silence leaves many questions unanswered. The recent leak demonstrates the difficulties of operating and maintaining an aging laboratory like the ISS in space’s extreme conditions. Engineers work in secrecy to uncover the truth while the global audience remains hopeful for clear answers and a lasting resolution.