Have you ever been on a long-haul flight? How did you pass the time? Perhaps you watched an in-flight movie or read a book.

Well it would have to be a very long book to keep you amused for 520 days. That's how long six men are going to be sealed away from humanity in a warehouse in the suburbs of Moscow from tomorrow.

No, this isn't another weird reality TV show, but an experiment from the European Space Agency and Russia's Institute of Biomedical Problems to test the psychological impact of a manned mission to Mars.

The six astronauts will live in conditions approximating a real space mission. A 550-cubic-metre mock-up within the warehouse includes aninterplanetary spaceship, a Mars lander and a Martian landscape.

The group of six - which includes one Chinese astronaut, Wang Yue - will work, relax and sleep in eight-hour shifts, take two days off a week and shower once every ten days.

The test site includes a Martian landscape simulation

All communication with mission control will be subject to a twenty-minute delay to reproduce the effects of distance.

After 250 days, the astronauts will divide into two groups. Three will move to the Martian surfacesimulator for a month while the rest will remain 'in orbit'. Then the six will be reunited for a 240-day return journey to... well, the outside world.

Throughout, the organisers of the project will use cameras to monitor everything that happens 'on board'. They will gather new informationabout personal stress levels, emotional well-being and group dynamics.

Dr Maggie Aderin-Pocock, a scientist with the satellite manufacturer EADS Astrium, believes that the experiment will be extremely valuable. However, she points out that without the glory of being the first humans to visit the Red Planet, it could be hard for these pioneers to maintain motivation.

"It's far less likely this would be a problem if you really were going to Mars", she says. "But the danger is that because you know you're really in a hangar in Moscow, you start thinking: 'I can't be bothered'."