A billionaire spacewalker returned to Earth with his crew on Sunday, ending a five-day trip that lifted them higher than anyone has travelled since Nasa’s moonwalkers.

SpaceX’s capsule splashed down in the Gulf of Mexico near Florida's Dry Tortugas, carrying tech entrepreneur Jared Isaacman, two SpaceX engineers and a former Air Force Thunderbird pilot.

They pulled off the first private spacewalk while orbiting nearly 740 kilometres above Earth, higher than the International Space Station and Hubble Space Telescope.

Their spacecraft hit a peak altitude of 1,408 kilometres following Tuesday’s liftoff.

Isaacman became only the 264th person to perform a spacewalk, since the former Soviet Union scored the first in 1965, and SpaceX’s Sarah Gillis the 265th.

Until now, all spacewalks were done by professional astronauts.

During Thursday's commercial spacewalk, the Dragon capsule’s hatch was open barely a half-hour.

Isaacman emerged only up to his waist to briefly test SpaceX’s brand new spacesuit followed by Gillis, who was knee high as she flexed her arms and legs for several minutes.

Gillis, a classically trained violinist, also held a performance in orbit earlier in the week.

The spacewalk lasted less than two hours, considerably shorter than those at the International Space Station.

Most of that time was needed to depressurise the entire capsule and then restore the cabin air.

Even SpaceX's Anna Menon and Scott “Kidd” Poteet, who remained strapped in, wore spacesuits.

SpaceX considers the brief exercise a starting point to test spacesuit technology for future, longer missions to Mars.

This was Isaacman’s second chartered flight with SpaceX, with two more still ahead under his personally financed space exploration programme named Polaris after the North Star.

He paid an undisclosed sum for his first spaceflight in 2021, taking along contest winners and a pediatric cancer survivor while raising more than US$250 million for a children's hospital.

For the just completed so-called Polaris Dawn mission, the founder and CEO of the Shift4 credit card-processing company shared the cost with SpaceX.

Isaacman won’t divulge how much he spent. (AP)