Photo of the Day

Associated Press
This Nov. 15, 2013 photo released by NASA shows the three-story Human Exploration Research Analog habitat at the Johnson Space Center in Houston. The space agency, which is contemplating a future journey to Mars, is working with a military laboratory at the submarine base in Groton, Conn., to measure how teams handle stress during month-long simulations of space flight. (Bill Stafford/NASA via AP)

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