WION Decodes | ISS has been leaking for nearly 7 years – Why haven’t we fixed it?

The International Space Station has been quietly leaking air into space for nearly seven years. What started as a minor issue in 2019 has now turned into a significantly concerning issue on the orbiting lab. Despite multiple repair attempts, patches, and continuous monitoring, the leak has never been permanently fixed. The problem has gained renewed focus when new leaks were detected in the same region. But the question remains, why is the leak still not fixed despite causing trouble for nearly a decade now?

On Friday (Jun 5), astronauts were briefly placed on alert and instructed to follow “safe haven” procedures, moving into the docked SpaceX Crew Dragon spacecraft to prepare for a potential emergency evacuation if conditions worsened. While the situation was stabilised and no evacuation was ultimately required, the incident underscored a troubling reality: this is not a resolved issue, but an ongoing one.

The leak originates from the Russian Zvezda module, specifically in a transfer tunnel used for docking spacecraft. Over time, engineers have identified not one but multiple microscopic cracks in the station’s structure that expand and shift under stress. The ISS is not dealing with a single failure, but an evolving one.

Why is ISS experiencing leaks?

In the unforgiving space environment for materials, the lab experiences extreme temperature changes, from roughly -150 degrees Celcius in shadow to over 120 degrees Celsius in sunlight. Constant pressurisation cycle and decades of use also result in metal fatigue. In addition, small imperfections in welds or structure can slowly grow into cracks, and those cracks can turn into leaks. Being more than 25 years in orbit, way beyond its intended design life, the ISS is showing its age.

Why is repairing leaks on ISS so complex?

Repairing damage on a space lab is far more complex than repairing any other structure when on land. On Earth, engineers could disassemble parts, replace components, or apply precise fixes under controlled conditions. In orbit, none of that is possible. Astronauts must work in microgravity, where liquids like sealants behave unpredictably. Repairs are often carried out from inside the station using epoxy-like materials, which can temporarily plug leaks but cannot restore structural integrity. External repairs require spacewalks, which are risky, expensive, and limited in scope.

Complicating matters further is the uncertainty around the exact cause. Even after years of investigation, engineers have not reached a definitive conclusion. It is not known whether it is a manufacturing defect, stress from repeated docking, or simply long-term degradation. Without a clear root cause, any fix becomes a form of trial and error rather than a permanent solution.

Not just a technical issue

The issue is not merely a technical issue, but also a political one. The leak is located in the Russian segment of the ISS, which would require coordination between NASA and Roscosmos. Differences in assessment and approach can slow decision-making. Meanwhile, the station is expected to be retired around 2030, which raises a question of whether it is even worth investing in a complex and high-risk permanent fix.

As a result, space agencies have resorted to adopting a strategy of risk management. The leaking section can be isolated by closing hatches, and astronauts are trained to respond quickly in case of worsening conditions. The station continues to function safely, even with a small, controlled loss of air.

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