On Friday, NASA ordered the four astronauts and cosmonauts of the Crew-12 mission aboard the International Space Station (ISS) to move to the docked Crew Dragon spacecraft, put on their spacesuits, and prepare for a possible evacuation. This happened just as Roscosmos began a more extensive repair of an air leak in the Russian Zvezda service module. The leak itself had worsened earlier in the week — on Monday it doubled from about half a kilogram to nearly a kilogram of air per day. Among the four crew members is French astronaut Sophie Adenot of the European Space Agency.
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What exactly happened
The order came on Friday. The four — two Americans, Adenot, and a Russian cosmonaut from the Crew-12 mission — moved to the SpaceX spacecraft and took up an "elevated safety position" so they could react quickly if conditions on the station worsened. NASA stressed that this was a measure taken "out of an abundance of caution" and that it considered a worsening scenario unlikely. The crew was to remain within reach of the capsule until Russian technicians completed the repair. The leak itself increased sharply as early as Monday, when the Zvezda module began losing twice the amount of air compared to previous months.
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The crack that has worried NASA for years
The leak is not new. It originates from the narrow PrK transfer tunnel, which connects the Zvezda module to one of the docking ports, and both Russia and NASA have been monitoring cracks in it since 2019. In 2024, NASA elevated the issue to the highest level in its internal risk registry, and the phrase "catastrophic failure" was even used in meetings. Since then, Roscosmos has been mitigating the leak by keeping the hatch to the leaking tunnel closed most of the time, essentially isolating it from the rest of the station. After the leak appeared to stabilize in early 2026, it returned in early May — and worsened sharply this week.
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Why Washington and Moscow don't agree
At the heart of the problem is the fact that the two agencies have been unable for years to agree either on the cause of the cracks or on how serious the risk is. NASA is concerned about the structural integrity of the tunnel and acknowledges a scenario of sudden failure; the Russian side does not consider a catastrophic rupture of the module to be realistic and focuses instead on the ongoing detection and sealing of cracks. "The PrK transfer tunnel has suffered from cracks and leaks for some time, and Roscosmos has so far mitigated them as best it could," said NASA spokesperson Bethany Stevens, adding that both agencies are cooperating on the issue.
SpacePolicyOnline ↗
What "evacuation" means in practice
Moving to the Crew Dragon does not mean the crew is leaving the station. The spacecraft is permanently docked to the ISS and serves as a lifeboat — in an emergency, it can undock and land on Earth within a few hours. Friday's order was thus a safeguard, not a departure: the astronauts were ready, but remained on the station. NASA had already
indefinitely postponed a private astronaut mission that was supposed to fly to the station because of the same leak — so the leak is also affecting commercial flights, not just the permanent crew.
SpaceNews ↗
A station at the end of its life
The episode fits into a larger story: the ISS is aging, and its most notorious weak point is precisely the cracks in the Russian PrK tunnel. The station is due to be decommissioned after 2030 and deliberately deorbited into the atmosphere — NASA has commissioned a special vehicle from SpaceX for this purpose. This approaching end adds another dimension to the dispute over the Russian module: repairs to the aging structure are becoming increasingly difficult, and the question of how much longer Zvezda can safely hold up is growing more urgent.
ZME Science ↗
What hotinfo is following
- Whether Roscosmos announces the outcome of Friday's repair and when the crew ends its standby in the Crew Dragon spacecraft.
- Whether the leak comes back under control, or NASA proceeds with returning the crew to Earth.
- How the long-running NASA–Roscosmos dispute over the cause of the cracks will affect plans to extend or end the ISS.
- The fate of postponed commercial missions tied to the Russian segment of the station.
