Six volunteer astronauts emerged from a 'trip' to Mars on Friday, waving and grinning widely after spending 520 days in seclusion.
Crowds handed each member of the group a red rose after their capsule opened at the facility in Moscow.
Scientists placed the six male volunteers in isolation in 2010 to simulate a mission to Mars, part of the European Space Agency's experiment to determine challenges facing future space travelers.
The six, who are between ages 27 and 38, lived in a tight space the size of six buses in a row, said Rosita Suenson, the agency's program officer for human spaceflight.
During the period, the crew dressed in blue jumpsuits showered on rare occasions and survived on canned food. Messages from friends and family came with a lag based on the simulated distance to Earth.
While they had a few luxuries a Christmas tree and a Halloween party they spent most of their seclusion gathering data to help future space travel.
The simulated trip replicated all aspects of a real spaceflight to Mars, including orbiting the planet, landing and returning to Earth.
"This was like taking a psychological trip to Mars ... it was the first full-duration of a human mission to Mars," Suenson said.
Though it did not expose the six volunteers from China, Russia and Europe to the weightlessness and radiation of a space mission, it replicated an important aspect of space travel.
"The study is helping to determine key psychological and physiological effects of being in such an enclosed environment for such an extended period of time," the space agency said.
Data from the mission will give experts an idea of how the mind and body would cope with a long spaceflight to the Red Planet, according to Suenson.
On their return Friday, the Mars500 crew addressed the media briefly and urged experts to put their data to good use. They will meet select family members and undergo quarantine for four days.
Extra seclusion will allow them to get reacquainted with their surroundings, including sound and light, Suenson said.
The six had personal items such as books, films and personal laptops during their stay at the facility in Moscow's Institute for Biomedical Problems.