NASA has delayed the launch of four crew members on a privately funded mission to the International Space Station until further notice due to an air leak in one of the orbiting lab’s Russian modules.
The flight, organized by Houston-based company Axiom Space, was already postponed earlier this week after SpaceX engineers discovered a fuel leak on the Falcon 9 rocket that was to carry the foursome into low-Earth orbit.
The mission was scheduled to lift off Wednesday morning from NASA’s Kennedy Space Center in Florida. A new targeted launch date has not yet been announced.
NASA said there is an ongoing investigation into the air leak in the Russian-built Zvezda service module. The agency said it is working with Russia’s space agency, Roscosmos, to “understand a new pressure signature” after recent repair work was completed in a rear section of the module.
“Cosmonauts aboard the space station recently performed inspections of the pressurized module’s interior surfaces, sealed some additional areas of interest, and measured the current leak rate,” NASA officials said in a statement. “Following this effort, the segment now is holding pressure.”
The agency said the delay will give both NASA and Roscosmos a chance to determine if any additional fixes are required.
Meanwhile, SpaceX said it needs time to repair a liquid oxygen leak that was detected during an inspection of the Falcon 9 booster. Liquid oxygen is one of the propellants used to fuel the rocket’s engines.
“Once complete — and pending Range availability — we will share a new launch date,” SpaceX said on X about the repair work.
When it does get underway, the mission is expected to last about two weeks at the International Space Station.
The flight, known as Ax-4, will be led by retired NASA astronaut Peggy Whitson, who has already logged a record 675 days in space — more than any other American astronaut. Joining her will be pilot Shubhanshu Shukla, an astronaut with the Indian Space Research Organization; mission specialist Sławosz Uznański-Wiśniewski, a Polish scientist with the European Space Agency; and mission specialist Tibor Kapu, a mechanical engineer from Hungary.

Shukla, Uznański-Wiśniewski and Kapu will make history by becoming the first people from their countries to live and work on the International Space Station.
During their two-week stay at the orbiting lab, the Ax-4 crew members will conduct a host of scientific experiments, according to NASA, including studies of muscle regeneration, how sprouts and edible microalgae grow in microgravity and how tiny aquatic organisms survive at the ISS.
The upcoming flight will be Axiom Space’s fourth crewed mission to the International Space Station. The company’s first private expedition to the ISS was in 2022 with an all-civilian crew.
The price tag for the Ax-4 mission has not been publicly disclosed, but space tourists reportedly paid around $55 million per seat on previous Axiom Space expeditions.

