I mentioned this mission back when it started, and now it is nearing completion (you may need a New Scientist login to view that article). What I’m talking about is Mars 500, an experiment to test the psychological stresses of long-term spaceflight, such as what would be required on a trip to the Red Planet.
the “spacecraft”: a set of interconnected cylindrical modules. The windowless chambers are locked and soundproofed, with air and water piped in. The six volunteers inside eat only what they brought and what they can grow.
They also simulate the communication delays, with messages taking an appropriate amount of time to reach them, so they have to solve problems on their own. It’s neat stuff. I wonder if that French guy’s guitar survived the ‘trip’, though.