What are the astronauts preparing for?

Three Russians, an Italian-Colombian, a Frenchman and a Chinese are making final preparations before spending 520 days inside a mock spaceship.
    The Mars-500 mission at Moscow’s Institute of Biomedical Problems willTEST the psychological and physical effects of long-term isolation on humans. The crew’s commander, engineer Alexei Sytev, looks at the three square meters that will be his personal space. "This phone will work only for 11 days, when we are near the Earth, but it will be switched off later." Sytev is a newlywed. He says leaving his wife is just one of the difficulties he’s preparing for.
    "I think the most difficult thing will be to be separated from the people that I am used to, and leaving behind some of the habits—all our activity will be directed towards a certain goal. I won’t see sunsets, sunrises, won’t feel rain for 18 months. That will be hard."