Five hundred days locked in a windowless container outside Moscow sounds like some sort of Soviet-era re-education scheme. It would certainly be enough to drive one crazy - which, in a way, is exactly the point.
But while most people would assume it takes a madman to volunteer for such a regime in the first place, the six men who have just completed a year of this isolation experiment - and will remain in their can until November - are hugely qualified for the ordeal. Russia's Institute of Biomedical Problems and the European Space Agency chose an engineer, a space scientist, a military physician, a surgeon, a navy diver and a trainee astronaut to "crew" their Mars 500 simulated 18-month mission to the Red Planet and back.
Could you last 500 days?
Modern spaceflight owes much to the institute, which has been testing the psychological and medical effects of isolation since the 1960s. But as the institute points out, an interplanetary journey with no hope of emergency intervention from Earth poses vastly greater emotional and medical challenges than mere orbital life.
Encouragingly, the Mars 500 crew are apparently still sane and getting along with each other.
An actual Mars mission would demand technology, finance and political will beyond anything available today. But if the time ever does come to venture beyond Earth, at least we'll have some idea of whether or not a human crew could stand to do it.