This 3 june it will be one year since the Mars 500 experience started: one year since six volunteers are locked inside a sealed nest of modules at Moscow's Institute for Biomedical Problems (IBMP).
The isolated crew will stay a total of 520 days, the time it would take to fly to Mars and back, so they are supposed to be inside their fake spaceship until next 5 November.
Mars 500 is the most realistic spaceflight simulation possible without leaving the ground.
This story gives the status on the experiment with words from Romain Charles and Diego Urbina the two European "marsonauts".
More backgroud information can be found on: http://www.esa.int/SPECIALS/Mars500/index.html