SpaceX leak puts off Axiom-4 launch again

The launch of the Axiom-4 space mission, piloted by India’s Group Capt Shubhanshu Shukla to the International Space Station (ISS), was postponed again on Wednesday as SpaceX teams required additional time to repair a liquid oxygen (LOx) leak detected in the rocket. No new launch date has been announced yet.

Snag that hit launch

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The Falcon 9 rocket’s liquid oxygen (LOx) leak was detected during a static fire test, where super-cooled oxidiser escaped from the propulsion bay

Since LOx is critical for combustion and highly flammable, SpaceX delayed the launch to repair it to ensure crew safety before liftoff

“SpaceX is standing down from Falcon 9’s launch of Axiom Mission 4 (Ax-4) to the ISS from Launch Complex 39A (LC-39A) at NASA’s Kennedy Space Centre in Florida on Wednesday to allow additional time for teams to repair the LOx leak identified during post-static fire booster inspections. Once complete -- and pending range availability -- we will share a new launch date,” SpaceX said in a statement.

The mission will be commanded by Peggy Whitson, a former NASA astronaut and Axiom Space’s director of human spaceflight, while Shukla will serve as the pilot. The two mission specialists are ESA (European Space Agency) project astronaut Sławosz Uznanski-Wisniewski of Poland and Tibor Kapu of Hungary.

Dr V Narayanan, Chairman, Indian Space Research Organisation (ISRO), who is currently in Florida, provided further details, “As part of launch vehicle preparation to validate the performance of the booster stage of Falcon 9 launch vehicle, a seven-second hot test was carried out on the launch pad. It is understood that an LOx leakage was detected in the propulsion bay during the test. Based on discussions by the ISRO team with experts from Axiom and SpaceX, it has been decided to correct the leak and conduct necessary validation tests before clearing the launch.”

The Falcon 9, a reusable two-stage rocket designed and manufactured by SpaceX, is intended for transporting crew and payloads into Earth’s orbit and beyond. The Axiom-4 mission would have marked the second flight of this particular Falcon 9, which previously flew on a Starlink mission in April this year. Falcon 9 is the world’s first reusable rocket.

A leak in a pressurised system occurs due to cracks, holes, porosity or faulty joints, allowing the escape of liquid or gas. Officials said the leak in the rocket might have originated during its last Starlink mission.

The issue was detected during a static fire test, a standard engine check conducted while the rocket remained secured to the launch pad, revealing LOx escaping from the propulsion compartment.

An official highlighted the risks, saying, “Leakage could ignite in the presence of an ignition source, potentially leading to catastrophic loss of the vehicle and crew. Excessive leakage could also cause launch delays and significantly increase programme costs.”

LOx serves as an oxidiser, enabling combustion even in the vacuum of space and generating the thrust necessary for space travel.

During a pre-launch press conference, William Gerstenmaier, SpaceX vice-president of build and flight reliability, said, “We had previously seen a leak on this booster during its entry on its last mission and discovered that it had either not been fully repaired during refurbishment or not detected. We are installing a purge that will essentially mitigate the leak, ensuring we are fully ready to proceed with the launch.”

Some engine-related issues had already been addressed, but further repairs were deemed critical. An ISRO official said, “The issues must be rectified before launch, as human lives are at stake. After discussions, it was decided to temporarily put the launch on hold. Once repairs are completed, another validation test will be conducted before proceeding with the launch.”

Dana Weigel, manager of NASA’s International Space Station Programme, earlier said the Axiom-4 mission had multiple launch opportunities available until the end of June or mid-July.