A spacecraft carrying a crew of four civilians has returned to Earth. They include a tech entrepreneur and an engineer who performed the world's first commercial spacewalk during the mission.

The Crew Dragon capsule of the private US firm SpaceX re-entered Earth's atmosphere on Sunday. It slowly descended using parachutes and splashed down into waters off the coast of Florida.

A ship on standby recovered the capsule, allowing the crew to step out of it. They shook hands with officials and waved toward cameras.

The capsule was launched into space from the Kennedy Space Center in Florida on Tuesday before entering an orbit around Earth.

Two of the crew, including US IT firm founder Jared Isaacman, carried out a private spacewalk on Thursday, wearing a spacesuit developed by SpaceX. It was the first spacewalk by civilians not belonging to any national space agency.

The trip in orbit was part of the Polaris Program, a space exploration initiative designed by Isaacman and others. The program involves sending more crewed flights to space.