The realities of a mission to Mars
Six men who were in total isolation for over 500 days on a simulated mission to Mars have emerged from their capsule in a Moscow warehouse.
For 18 months their routine mirrored life in a real spaceship. The project was aimed at testing how their minds and bodies would cope on a long-haul spaceflight.
The BBC's Jonathan Amos reports on the realities of a mission to Mars.