Japanese billionaire Yusaku Maezawa on Saturday canceled his planned flight around the moon on a SpaceX vehicle because of uncertainty about when it may be possible.

The tycoon in 2018 launched plans for the lunar flyby voyage. He bought seats for eight traveling companions in 2022 for what would be his second space journey after his 12-day trip to the International Space Station (ISS) on a Russian Soyuz spacecraft in 2021.

Maezawa was aiming the moon trip for 2023, a target seen by most space observers as overly optimistic given the progress of SpaceX's Spaceship mega-rocket project.

It would have been the first private flight around the moon.

That project became “unfeasible,” said the mission organizer on Saturday in a statement posted on its website. “Without clear schedule certainty in the near-term, it is with a heavy heart that Maezawa made the unavoidable decision to cancel the project.”

“To all who have supported this project and looked forward to this endeavor, we sincerely appreciate it and apologize for this outcome,” it said.

Maezawa had selected eight people for his “dearMoon” project from 1 million applicants. They included a lead rapper for the K-pop group Big Bang, and Americans DJ Steve Aoki and filmmaker Brendan Hall.

Separately on Saturday, Maezawa said in his message on X: “I can't plan my future in this situation and I feel terrible making the crew members wait longer, hence (I made) the difficult decision to cancel at this point in time.”

“I apologize to those who were excited for this project to happen,” he said.

He said he signed the contract with SpaceX in 2018 assuming the launch would be possible by the end of 2023. “It's a developmental project so it is what it is, but it is still uncertain as to when Starship can launch.”

SpaceX's two test flights of its mega-rocket last year ended in explosions minutes after liftoff. In a third test in March, its spacecraft was lost as it descended back to Earth.

Maezawa and his producer in December 2021 became the first self-paying tourists to visit the space station since 2009.

Maezawa made his fortune in retail fashion, launching Japan's major online fashion mall, Zozotown.