The Polaris Dawn crew tries out their new spacesuits.SpaceXSpaceX's Polaris Dawn mission is about to attempt the first-ever commercial spacewalk.Four people plan to don new spacesuits and open their Crew Dragon spaceship to the vacuum of space.Watch the historic, risky operation live on Thursday.A billionaire-backed SpaceX mission is about to attempt a daring, first-of-its-kind feat.On Thursday, four people currently orbiting Earth in a SpaceX Crew Dragon spaceship plan to don a set of brand-new spacesuits, open their spaceship's hatch to completely expose its interior to the vacuum of space, and attempt the first-ever commercial spacewalk.Their week-long mission, called Polaris Dawn, is fully private with no NASA involvement — but it's no billionaire joyride.