ISS leaks push Axiom Mission 4 launch to no earlier than June 19

Evaluation of latest repairs to Russian segment ongoing

NASA has pushed back the launch of Axiom Mission 4 to the International Space Station (ISS), citing concerns over persistent leaks aboard the aging orbital outpost. A new No Earlier Than (NET) date is set for June 19.

Concerns over ISS leaks have been mounting for some time. The orbiting laboratory is getting long in the tooth, and the Russian segment is beset by small cracks, resulting in leaks and drops in pressure.

NASA said it worked with Russia's space agency, Roscosmos, "to understand a new pressure signature, after the recent post-repair effort in the aft-most segment of the International Space Station's Zvezda service module."

As of the weekend, NASA said pressure was now "stable" where before it would have dropped. This could indicate the latest repair effort was successful. That said, the stabilization could be caused by air flowing into the transfer tunnel across the hatch seal from the main part of the ISS.

It isn't clear what form the most recent repairs took. In a chat with The Register, one wag joked that a combination of glue, duct tape, and hope was used. We asked Roscosmos for details of the repairs and will update the article should it respond.

European Space Agency astronaut Andreas Mogensen told The Register in a 2024 interview that, in the worst case, the Zvezda hatch could be permanently sealed without impacting ISS operations too badly. "As long as Russia is willing to forego that docking port."

The Crew Dragon for Axiom Mission 4 is due to dock with a port on the ISS Harmony module, launched in 2007 on the STS-120 mission.

The leak rate featured prominently in a 2024 report from the NASA Office of Inspector General, where the watchdog noted that "NASA and Roscosmos have not reached an agreement on the point at which the leak rate is untenable."

Other observers, including billionaire Elon Musk, have warned of the risks of keeping the ISS going. "Some parts of it are simply getting too old and obviously that risk grows over time," Musk said on his social media platform, X.

"Even though @SpaceX earns billions of dollars from transporting astronauts & cargo to the ISS, I nonetheless would like to go on record recommending that it be de-orbited within 2 years."

The latest change in date for the Axiom Mission 4 launch comes after SpaceX repaired the liquid oxygen leak identified during post-static fire Falcon 9 rocket inspections. The company has since successfully completed a wet dress rehearsal (where the rocket is loaded with fuel but the engines are not ignited). ®