Further ISS leak delays the next commercial Axiom space mission

After the Axiom-4 private space mission to the International Space Station (ISS) was initially postponed due to a fuel leak on the SpaceX rocket, NASA now has a major problem that is further delaying the launch of Ax-4. The ISS is losing air pressure again, even though a leak on the Russian part of the station had just been sealed. The new leak will first be investigated in more detail, meaning that the launch of Axiom-4 will not take place until June 19 at the earliest.

The fourth commercial Axiom space mission, with which an Indian, a Hungarian, and a Pole were to fly to the ISS space station for the first time last Wednesday, was postponed at short notice due to a technical issue. During an inspection, a liquid oxygen leak was discovered on the rocket. This was apparently repaired quickly so that the mission could have been launched just two days later. However, a new ISS leak was then discovered, which caused a further delay.

The search for ISS leaks

Leaks from the space station are nothing new, as oxygen has been escaping from a Russian module of the ISS since 2019. The Russian space agency Roskosmos has had its astronauts make several attempts to seal them. The leaks were located in an airlock, known as PrK for short, which connects the Russian service module called Zvezda with the rest of the station. This module is the oldest part of the ISS and was launched back in 1998. Most recently, the hatch to the PrK was therefore kept as closed as possible to minimize the impact of the leaks on the ISS as a whole.

However, a few days ago, Roskosmos apparently announced that the leaks in the Zvezda module had been completely sealed. However, the air pressure in the entire space station continues to drop, reports Ars Technica, citing two sources. It is speculated that the seals on the hatch to the PrK airlock are not completely closed. This would result in the ISS air pressure leaking into the airlock, giving the impression that PrK is sealed due to stable air pressure – but at the expense of the air pressure of the rest of the station.

Leaks get bigger as the ISS gets older

According to NASA, this is now being checked by changing the air pressure in the airlock and observing it over a certain period of time. Although the problem was discovered more than five years ago, twice as much air has been escaping from the leak in the Russian ISS segment since the beginning of 2024. Apparently, the leaks had become noticeably larger. NASA has assured us that the issue is “manageable” and within the permitted specifications. Nevertheless, work is underway to close it. The crew is therefore not in danger.

However, the ISS will not have any more occupants until NASA has got to the bottom of the reason for the space station's falling air pressure or at least learned more about it. The private Axiom-4 space mission has therefore been postponed until Thursday. The crew is therefore scheduled to take off from Launch Complex 39A at Cape Canaveral Spaceport in Florida on June 19 at the earliest, using a Falcon 9 rocket on board a SpaceX Crew Dragon capsule.

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