On Wednesday, three men and three women will step inside a thousand-square-foot dome on the north side of the Mauna Loa volcano in Hawaii. For the next eight months, they will be cut off from the outside world. The team will simulate life at a space station on Mars as part of a project called HI-SEAS, sponsored by NASA and led by the University of Hawaii at Manoa. The eight-month project is the second of three missions sponsored by NASA studying human performance on long-duration isolation missions. It's NASA's longest Mars simulation to date. Martha Lenio, 34, of Canada, is the mission's commander and the first woman to lead a Mars simulation. She's the third woman in NASA's history to lead a mission of any kind. National Geographic talked to Lenio as she prepared to enter the dome. What's the goal of the mission? Read interview via Nat Geo.