Jocelyn Dunn spent eight months living on the red, rocky surface of Mars. Last year she shared a 1,000-square-foot habitat with five crewmates, wore a space suit every time she stepped outside, and showered for just six minutes a week. Or at least, she was as close to experiencing Mars as any human (including Matt Damon) can get right now. Dunn, an engineer, was participating in the third mission of HI-SEAS (Hawaii Space Exploration Analog and Simulation), which takes place on the barren slopes of Hawaii's Mauna Loa volcano. The NASA-funded study probes how potential astronauts will react to isolation, confinement, and the extreme environment of life on another planet. Popular Science recently spoke with Dunn—the mission's chief scientist and a real-life Martian (almost).