See SpaceX’s Polaris Dawn mission: The daring 5-day spaceflight that’s revolutionized the commercial space industry

They launched into space aboard a Crew Dragon spaceship on September 10.

That sent them through the Van Allen belts, a pair of donut-shaped regions of extreme radiation around Earth.

They wore “smart” contact lenses to measure the pressure in their eyes.

On September 12, it was time for the mission’s main event: a daring and risky spacewalk, the first-ever private spacewalk.

To prepare, the crew conducted a 48-hour “pre-breathe” before opening the spaceship’s hatch and exposing the ship and everyone aboard to the vacuum of space. Without the “pre-breathe” the crew would be at risk of a dangerous effect called “the bends.”

Finally, it was time to open the Dragon’s hatch and climb the railing into space. Isaacman and Gillis left the spacecraft to perform tests on their spacesuits.

Isaacman and Gillis each took turns standing in space and testing their suits’ mobility. You can watch the whole spacewalk on SpaceX’s broadcast, below.

“Stepping out and seeing kind of the cusp of the world is absolutely incredible,” Gillis told The Washington Post a few hours later.

Polaris Dawn was a mission of historic firsts. Lifelong violinist Gillis became the first person to play a violin solo in space.

Then it was time to strap in for the return journey home.

“We are mission complete,” Isaacman radioed from the capsule as it bobbed in the water. Shortly after, a SpaceX ship recovered the capsule, and the crew emerged after their successful five-day mission.