The highly anticipated Axiom-4 (Ax-4) mission to the International Space Station (ISS), which was set to mark a historic milestone for India, Poland, and Hungary, has been postponed following the detection of a liquid oxygen (LOx) leak in SpaceX's Falcon 9 rocket during post-static fire booster inspections. SpaceX announced the delay on June 11, 2025, stating that additional time is required to repair the leak and conduct necessary validation tests before the launch can proceed. The company emphasized that a new launch date will be shared once repairs are completed and range availability is confirmed.

The LOx leak was discovered after a routine seven-second hot test of the Falcon 9 booster, a standard procedure to validate the rocket's performance ahead of launch. This specific booster had previously flown a Starlink mission and was undergoing refurbishment when the leak, initially undetected, became apparent during the recent test. SpaceX's Vice President of Build and Flight Reliability, William Gerstenmaier, acknowledged that the leak had also been present during the booster's previous mission and was not fully repaired during refurbishment.

As a result, SpaceX and its partners, including the Indian Space Research Organisation (ISRO) and Axiom Space, decided to address the issue thoroughly before proceeding, prioritising crew safety and mission success.

The Ax-4 mission holds particular significance as it is set to carry Group Captain Shubhanshu Shukla, who will become the first Indian Gaganyaatri (astronaut) to visit the ISS and only the second Indian in space since 1984. The crew also includes Sławosz Uznański from Poland, Tibor Kapu from Hungary, and veteran astronaut Peggy Whitson, who will command the mission. This flight represents the first government-sponsored human spaceflight mission for India, Poland, and Hungary in over four decades, and the first time these nations will send astronauts to the ISS. The mission is a testament to growing international collaboration in space and aims to advance the national space programs of the participating countries.

Beyond its symbolic importance, Ax-4 is designed as a 14-day mission focused on scientific research and international cooperation. The crew will conduct approximately 60 scientific studies and activities representing 31 countries, making it the most research-intensive Axiom Space mission to date. These studies will span human research, Earth observation, and life, biological, and material sciences, showcasing the research capabilities of the crew's home nations and contributing to global knowledge in microgravity science.

ISRO Chairman V. Narayanan, who is overseeing the mission in the United States, confirmed that the decision to postpone was made after discussions with experts from Axiom Space and SpaceX. He reiterated that the leak must be corrected and the booster revalidated before the mission can be cleared for launch, underlining the commitment to safety and technical rigor.

Despite the delay, the Ax-4 mission remains a beacon of opportunity and inspiration, particularly for India. Group Captain Shubhanshu Shukla expressed his pride in representing his country and his hope that his journey will inspire a new generation of Indian youth to pursue careers in science and space exploration. The mission's postponement, while disappointing, reflects the complexities and challenges of spaceflight and the unwavering dedication of all partners to ensuring a safe and successful mission.

The Ax-4 mission's postponement due to a liquid oxygen leak in the Falcon 9 rocket underscores the technical challenges inherent in human spaceflight. However, the mission's eventual launch will mark a historic return to space for India, Poland, and Hungary, fostering international collaboration and advancing scientific research on the ISS.

Agencies