The mission, known as Polaris Dawn, is designed to carry four crew members to the highest orbital altitude that humans have reached since 1972.

A SpaceX capsule carrying four private citizens blasted off early Tuesday on a five-day mission that is set to include the first spacewalk carried out by an all-civilian crew.

The mission, known as Polaris Dawn, lifted off at 5:24 a.m. ET from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.

The flight is designed to carry the four crew members to the highest orbital altitude that humans have reached since the final Apollo moon mission in 1972: 870 miles above Earth’s surface. That’s more than three times higher than the International Space Station. While in space, the group will test new spacesuits and technologies that could pave the way for future long-duration missions to the moon and eventually Mars.