The SpaceX launch of four private astronauts has been delayed again. The Ax-4 mission to the International Space Station (ISS) had been scheduled to launch atop a SpaceX Falcon 9 rocket from Florida's Space Coast on Wednesday morning (June 11), but a propellant leak in the booster nixed that plan.

The Axiom-4 mission launch, the fourth private astronaut mission to the International Space Station, was canceled Tuesday night after SpaceX detected a liquid oxygen leak in its Falcon 9 rocket.

The first of back-to-back rocket launch days used a familiar booster. The Starlink mission took off on June 10, with an astronaut mission to follow.

SpaceX’s first launch of the Falcon 9 took at Cape Canaveral in Florida on June 4, 2010. The inaugural flight marked a significant milestone in commercial spaceflight history as it was the first time that a privately developed rocket of Falcon 9’s size had been successfully launched to orbit.

Another SpaceX Falcon 9 rocket is due to launch over the weekend from Southern California's Vandenberg Space Force Base.

The next rocket launch from Vandenberg Space Force Base in Southern California is due to liftoff Friday, May 16.

SpaceX has delayed the scheduled Wednesday launch of its Ax-4 mission to the International Space Station to allow time for repairs following the discovery of a liquid oxygen leak.

A group of private spacefarers that includes one of NASA's most seasoned astronauts is waiting an extra 24 hours to make a short trip up to the International Space Station. A venture known as Axiom Mission 4 was due to get off the ground on the morning of Tuesday,

SpaceX has postponed the Axiom-4 mission to the ISS carrying Shubhanshu Shukla after detecting an LOx leak in the Falcon 9 rocket. The launch will be rescheduled after repairs and range clearance, says the company.