Mock Mission To Mars

The seven volunteers for the Mars-500 experiment, only six of which actually entered the simulator: Aleksei Sitev, Aleksandr Smoleyevsky, and backup Mikhail Sinelnikov (left to right, front row) and Sukhrob Kamolov, Romain Charles, Diego Urbina, and Wang Yue (left to right back row)

A general view of the "confinement modules" where scientists will conduct the Mars-500 experiment.

A technician works inside one of the aptly named "confinement modules."

Romain Charles of France, 31, says the hardest things will be the disruption of contact "with the family, the girlfriend, the friends with whom the distance is going to be difficult to manage."

The hatch will only reopen when the experiment is over or if one of the participants is forced to pull out.

Sukhrob Kamolov (right) of Russia attends a training session inside one of the modules in Moscow.

Backup Mikhail Sinelnikov undergoes medical checks before the experiment began.

The ultimate goal: the surface of Mars