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."