Falcon 9 leaks keep Axiom private astronaut mission on the ground

Weather and propulsion system problems conspire to keep astronauts away from the ISS

The Axiom-4 private astronaut mission to the International Space Station (ISS) has been held up by a liquid oxygen leak in the Falcon 9's first stage.

The leak was touched on during a pre-launch briefing on June 9, although there was no indication that it would present a constraint to launch. William Gerstenmaier, Vice President for Build and Flight Reliability at SpaceX, noted that the leak had been observed during the static fire, but expected troubleshooting to be complete before launch and said "we're installing a purge that will essentially mitigate the leak if it still continues, if we see it on launch day.

"So we'll be ready to go fly."

After later standing down from launch due to weather constraints, the decision was taken that, nope – the rocket was not ready to go fly, and repairs were needed.

While it is the first flight of this particular Crew Dragon spacecraft, it is the second for the booster, which was previously used to launch a Starlink mission. During the briefing, Gerstenmaier said a leak had been observed during the booster's entry on its last mission. However...

"We discovered that we'd not fully repaired the booster during refurbishment, or we didn't actually find a leak and didn't get it corrected."

A space industry insider told The Register that work on the engine feedline was needed, and that the next launch date was tentatively NET June 13. SpaceX and Axiom Space have not shared a new official launch date; SpaceX said it would depend on when work was completed and range availability.

The mission crew is commanded by former NASA astronaut Peggy Whitson, director of human space flight at Axiom Space. It includes ISRO (Indian Space Research Organisation) astronaut Shubhanshu Shukla, who will serve as pilot, and a pair of mission specialists: ESA (European Space Agency) project astronaut Sławosz Uznański-Wiśniewski of Poland and Tibor Kapu of Hungary.

The crew will spend approximately two weeks at the ISS and perform about 60 science experiments and demonstrations.

The mission is due to launch from Launch Complex 39A at Kennedy Space Center, and the first stage is expected to land on Landing Zone 1 at Cape Canaveral Space Force Station in Florida.

Managers have a little room for maneuver regarding launch dates, with more opportunities in June and July. Later than that, however, risks conflicting with the requirements for the Crew 11 mission this summer, which Gerstenmaier said would be using the same first-stage booster. ®