Six volunteers will soon lock themselves inside an experimental mock spaceship in Russia for more than a year to see what it is like to be the first astronauts to visit Mars — without actually leaving planet Earth.

Slated to begin this summer, the 520-day experiment is the first full-duration simulated mission to Mars. Called Mars500, the experiment will mimic a mission to the red planet and back as accurately as possible, including rationed supplies and staged emergency situations. The isolation test consists of a mock interplanetary spaceship, a Mars lander and martian landscape.

It is the last and biggest part of the Mars500 experiment, which began in November 2007 and consisted of a 14-day simulation that tested facilities and operational procedures. Phase two took place in March 2009, when six crewmembers were shut in the facility for 105 days.

This latest experiment, which researchers say will help to prepare for future human missions to the Moon and Mars, will be conducted by Russia’s Institute of Biomedical Problems, with extensive participation by the European Space Agency (ESA) as part of its European Program for Life and Physical Sciences.

The four European candidates, representing ESA for the mission, have been training in Russia since Feb. 24. Only two of those candidates will be selected to join the Mars500 crew, which currently includes one Chinese volunteer and three from Russia.

The full simulated Mars mission will take 520 days total — more than 17 months — starting off in a special facility in Moscow next summer. The mission will consist of 250 days for the trip to Mars and 30 days spent exploring Mars’ surface, during which half of the crew will move to the martian surface simulator while the three remaining crew members will stay in the mock spacecraft. The crew will then reunite for the 240-day return journey.

In all, the mission is more than twice as long as full tours aboard the international space station, which typically last about six months.

ESA and Russia’s Federal Space Agency are major partners in the $100 billion international space station along with NASA and the space agencies of Japan and Canada. In all, 16 different countries are involved in the project.

Simonetta Di Pippo, ESA’s director of human spaceflight, said that the Mars500 isolation study is a major milestone in the preparation and research of exploration missions.

“Mars is the ultimate goal of the global human exploration program,” Di Pippo said in a statement. “In addition to developing the necessary space infrastructure for exploration missions, ESA’s Directorate of Human Spaceflight also has an ongoing program of ground-based analogues and international space station research activities to make sure that our astronauts are as prepared as possible in the future for the physical and mental demands of long-duration exploration missions, and to develop countermeasures against any adverse effects of such a mission.”