sciencehabit writes "Imagine life on a spaceship headed to Mars. You and your five crewmates work, exercise, and eat together every day under the glow of fluorescent lights. As the months pass, the sun gets dimmer and communication with Earth gets slower. What does this do to your body? According to an Earth-based experiment in which six volunteers stayed in a windowless 'spaceship' for nearly a year and a half, the monotony, tight living space, and lack of natural light will probably make you sleep more and work less. Space, for all intents and purposes, turns you into a couch potato."