Six people will soon find out what it would be like to live on Mars by enclosing themselves in a Russian-built mock-up of the red planet for 520 days. The group is part of a European and Russian experiment, called Mars500, designed to provide a better understanding of the mental and physical challenges of such a long-duration expedition.

The experiment will start this summer. It follows a 14-day mission in the simulated chamber in 2007, and a 105-day mission last year. The new mission is the final phase of the experiment.

The facility, which mimics the red planet’s landscape, includes a mocked up interplanetary spaceship and Mars lander. For the simulation, the crew will spend 250 days in a spacecraft traveling to Mars, then 30 days exploring it’s surface, during which 3 people will move to the surface simulator and the others will remain in the spacecraft. The remaining 240 days will be spent traveling home.

During the mission, the crew will experience emergency situations like communication failures and food rationing, and will be required to conduct scientific experiments in an isolation chamber. Researchers hope to gather data on the crew’s psychological health–crews have to keep journals and fill out questionnaires throughout the experiment–to better prepare humans for the loneliness of extended exploration missions. The mission will be almost three times longer than the longest mission on the International Space Station (six months), and the participants will spend majority of that time in a small spacecraft journeying to the red planet.