The scheduled launch of the Axiom Mission 4 (Ax-4) to the International Space Station (ISS) has been postponed once again, SpaceX announced on X (formerly Twitter). The delay follows the detection of a liquid oxygen (LOx) leak during a post-test inspection of the Falcon 9 rocket’s booster.

"Standing down from tomorrow's Falcon 9 launch of Ax-4 to allow additional time for SpaceX teams to repair the LOx leak," the company posted, adding that a new date would be confirmed once repairs are complete and launch range availability is reassessed.

Indian Air Force officer Group Captain Shubhanshu Shukla is one of the astronauts scheduled to travel to the ISS as part of this mission. His participation marks a major milestone in India’s space journey, as he becomes the first Indian astronaut to head to space since Rakesh Sharma’s historic flight in 1984.

Earlier, SpaceX had reported favourable weather conditions—around 85%—for launch, although teams were keeping an eye on high-altitude winds along the rocket's path.

India’s space agency ISRO also acknowledged the delay. In a post, it explained that a seven-second static fire test of the Falcon 9’s booster stage had been conducted to validate performance, during which the LOx leak was discovered in the propulsion section.

"Based on discussions between ISRO, Axiom, and SpaceX experts, the teams decided to address the leak and conduct further validation tests before proceeding with the launch," ISRO stated, confirming the deferral of the June 11 liftoff originally intended to send the first Indian Gaganyatri to the ISS.

NASA, Axiom Space, and SpaceX also issued a joint statement via the ISS’s official X account, saying the launch attempt on June 11 would not go ahead as planned.

The Ax-4 mission is a collaborative effort involving Axiom Space, NASA, SpaceX, and ISRO. It marks India's re-entry into the realm of crewed space missions after a gap of over 40 years.

This latest delay is the fourth for the Ax-4 mission. A previous postponement was due to adverse weather forecasts, including a 45% likelihood of rain and concerns over strong winds at the launch site.

Once launched, the Ax-4 crew is expected to spend up to two weeks aboard the ISS, conducting a broad range of scientific studies. These experiments, covering fields such as life sciences, materials science, and the effects of microgravity, will be carried out in coordination with researchers from more than 30 nations.