Nov 1 (Reuters) -- The four members of a crew who took part in a simulated mission to Mars have emerged after 378 days in isolation at the US space agency's Johnson Space Center in Houston, an endeavor designed to help prepare for a possible future excursion by NASA astronauts to Earth's planetary neighbor. "It's been a hell of a year -- analog astronauts living in captivity of our own free will," Ellen Ellis, the medical officer on the Crew Health and Performance Exploration Analog, or CHAPEA, mission, said in remarks at Johnson Space Center after emerging with her three crewmates on Saturday.