The SpaceX Polaris Dawn mission, a daring multiday orbital expedition that will feature the first-ever spacewalk by private citizens, is targeting liftoff early Tuesday, though weather could play spoilsport.

If they launch, the highlight of the mission will be the first spacewalk composed entirely of non-professional astronauts, who will be wearing sleek, newly developed SpaceX extravehicular activity (EVA) suits outfitted with heads-up displays, helmet cameras, and an advanced joint mobility system.