Billionaire Jared Isaacman, who has chartered the first all-civilian orbital spaceflight, has announced three more private missions with SpaceX that will include a spacewalk and culminate in the first manned flight of the next-generation Starship rocket, AFP reported.

The first mission, called Polaris Dawn, will take place no earlier than the fourth quarter of this year and will be led by Isaacman, founder of payment processing company Shift4, according to the statement.

The cost of the flight was not disclosed, but it is expected to be in the hundreds of millions of dollars.

Isaacman is an experienced pilot who led the Inspiration4 mission last year, in which four civilian crews completed a three-day orbital mission aboard the SpaceX Dragon, raising $240 million for St. Jude Children's Research Hospital.

The crew, which includes former US Air Force Colonel Scott "Kidd" Poteet as pilot, and two SpaceX employees — flight specialist Sarah Gillis and flight specialist and medical officer Anna Menon — will attempt the first commercial spacewalk at an altitude of approximately 300 miles.