Two astronauts - a billionaire and an engineer - completed the world’s first private spacewalk in orbit on Thursday outside a SpaceX capsule, wearing a new line of spacesuits in a risky feat previously exclusive to astronauts from national space programs.

The astronauts on the Polaris Dawn mission went one at a time, each spending about 10 minutes outside the gumdrop-shaped Crew Dragon capsule on a tether, as Elon Musk’s company again succeeded in pushing the boundaries of commercial spaceflight.

Jared Isaacman, a pilot and the founder of electronic payments company Shift4, exited first, followed by SpaceX engineer Sarah Gillis, while crewmates Scott Poteet and Anna Menon watched from inside.

The whole process, unfolding about 450 miles (730 km) above Earth, lasted an hour and 46 minutes. The four astronauts have been orbiting Earth since Tuesday’s launch from Florida.

Isaacman is bankrolling the Polaris mission, as he did his Inspiration4 flight with SpaceX in 2021.

Streamed live on SpaceX’s website, the mission tested trailblazing equipment including slim spacesuits and a process to fully depressurize the Crew Dragon cabin - technology that Musk hopes to advance for ambitious future private missions to Mars.

“Back at home, we all have a lot of work to do. But from here, Earth sure looks like a perfect world,” Isaacman said after emerging from the spacecraft, silhouetted with the half-lit planet glittering below.

It was one of the riskiest missions yet for SpaceX, the only private company that has proven to be capable of routinely sending people to and from Earth’s orbit.

Before the spacewalk began at about 6:52 am ET, the capsule was completely depressurized, with the astronauts relying on their SpaceX-developed spacesuits for oxygen, provided through an umbilical connection to Crew Dragon.

Isaacman, 41, and Gillis, 30, rose from Crew Dragon’s hatch door into space to test various body movements in the suit, voicing feedback to ground control to inform future design iterations.

Their posture appeared stiff as they were able to move their arms at the elbow and shoulder but less so at the waist, back and neck.

The mission tested the spacesuit design and procedures for the capsule, among other things, in a mission meant to test the limits of what private companies can do in orbit.

Ground teams at SpaceX’s Hawthorne, California, headquarters watched as the capsule’s hatch door sealed shut and carried out leak checks as the astronauts returned to their cabin seats.

The first US spacewalk in 1965, aboard a Gemini capsule, used a similar procedure to the one used on Thursday: the capsule was depressurized, the hatch opened, and a spacesuited astronaut ventured outside on a tether.