BENGALURU: The launch of the Axiom-4 mission (Ax-4) has not just been delayed because of poor weather conditions and leak in the liquid oxygen cylinder, but due to many more reasons.
One of them is the detection of the increasing air leak in the Zvezda service module in the International Space Station (ISS) by the NASA team. The experts from ISRO also acknowledged this and said that this is one of the other reasons for the delay that has been happening since May 2025.
The ISRO and NASA teams said that the mission has been indefinitely postponed till things are corrected. ISRO has also stressed upon the need for in-situ repairs or replacements and better testing mechanisms before launching the 14- day long manned mission.
ISRO Chairman V Narayanan said they were closely working to address the issues. “Safety of the astronauts and the mission’s integrity is our top priority,” Narayanan said
The NASA team added that they are working with Roscosmos, Russia’s Space Agency, to understand the air pressure and its current impact because of the gas leak. The NASA team noted that the increasing air leak was noted during their recent inspection ahead of the Ax-4 launch.
The Zvezda module, developed by Russia and is an integral part of the International Space Station (ISS). which provides life support, living quarters, data processing systems, flight control systems, propulsion systems and communication systems to the astronauts in space from the ground control systems. Technical issues in this module will hamper the manned space missions.
The Module was launched in 2000. Though air leak was considered normal, in 2019 the leak was said to be around 0.45 kgs per day which is said to have increased to 1.67 kgs in 2024. However, NASA and Roscosmos differ on the air leak values.
Under the AX-4 mission, the Falcon-9 rocket will launch SpaceX’s Crew Dragon C213 and it will be docked into the ISS by ISRO’s Gaganyatri Group Captain Shubhanshu Shukla. He is one of the four Gaganyatris chosen by ISRO to be a part of the 14-day long Ax-4 mission.
ISRO also pointed out that the launch was first scheduled for May 29, 2025. But then it was postponed to June 8, 2025, because of the concerns in the electrical harness in the Crew Dragon Module, which was important for the transport of the crew. The mission was then again postponed to June 9, 2025, because of the delay in the preparedness of the Falcon-9 vehicle.
“Another reason for the delay was the anomaly in one of the engine actuator which was replaced along with the controller. ISRO has recommended carrying out in-situ repairs or replacement and conduct a low-temperature leak test to validate system performance and integrity, before proceeding with launch clearance,” ISRO team said.
Experts in ISRO said they have also recommended to NASA, Axiom Space and Roscosmos to evaluate the new pressure points that have indicated the air leak in the aft most segment of the ISS Zvezda Russian service module, after the recent repair attempt. Until test reports around are found to be satisfactory, the Ax-4 mission will stand postponed, ISRO experts said.