In 2010, six men were locked inside a simulated spacecraft on earth for 520 days. It was part of an experiment to see how humans would cope if cooped up together for the duration of a potential trip to Mars. The crew were monitored throughout and were treated as if they were on a real mission in space, though the spacecraft was actually housed in a warehouse in Moscow. They even performed a simulated space walk on the surface of Mars. The project was set up by Russia, China and the European Space Agency. Alex Last has been speaking to Diego Urbina (@DiegoU) who took part in the mission.

Photo: The six crew members of the Mars-500 mission. (From Left) Russia Alexey Sitev, France's Romain Charles, Russia's Sukhrob Kamolov, Russia's Alexander Smoleevskiy, Diego Urbina from Italy and China's Wang Yue. (Getty Images)