• 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)

    How to prepare for Mars? NASA consults Navy sub force

    GROTON, Conn. (AP) — As NASA contemplates a manned voyage to Mars and the effects missions deeper into space could have on astronauts, it’s tapping research from another outfit with experience sending people to the deep: the U.S. Navy submarine force.