Japanese billionaire Yusaku Maezawa cancelled his "dearMoon" mission, which the project said was to have been the first private flight around the moon, the mission announced on Saturday.

The team had originally aimed to make the circumlunar flight, with celebrities on board, by the end of last year but that became "unfeasible", the mission said in a statement 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," it said. "To all who have supported this project and looked forward to this endeavor, we sincerely appreciate it and apologize for this outcome."

The statement did not give further details on the cause of the cancellation. (Reuters)