Future Mars astronauts may be sleepy, bored & crabby

http://www.wired.com/wiredscience/2013/01/sleep-problems-mars-500/ / lethargic problems mental tasks long mission sleep Russian Academy of Science European Chinese space agency experiment six-man six 6 man crew simulated spaceship 520 consecutive days 24 hour sleep cycle schedule 25 hour day cohesion awake asleep psychological depression crew dynamics cohesion harmony biomedical researcher research behavioral health performance NASA Johnson Space Center sleep defect cognitive performance exercise lethargic mood disturbance disorder /