MOSCOW – It seemed more like a bizarre reality TV show than a high-tech international space travel experiment: Six men lived in cramped, windowless compartments for more than 17 months to simulate a mission to Mars.

When they emerged from their claustrophobic capsules Friday in western Moscow, the researchers in blue jumpsuits looked haggard but were all smiles — dreaming of lying in the sun at the beach, taking long strolls and driving fast cars.

Organizers said the 520-day experiment was the longest mock space mission ever, measuring human responses to the confinement, stress and fatigue of a round trip to Mars — minus the weightlessness, of course. They describe it as a vital part of preparations for a future mission to the Red Planet, even though it may be decades away because of huge costs and daunting technological challenges.

The facility at Moscow’s Institute for Medical and Biological Problems, Russia’s premier space medicine center, included living compartments the size of a bus, connected with several other similarly sized modules for experiments and exercise.

There have been other confinement experiments, including Biosphere 2, a giant glass-and-steel facility in Arizona in the 1990s that housed four men and four women in self-sustaining two-year isolation. That project was dogged by controversy and technical problems.

Scientists who organized the mock Mars mission said it differed from the other experiments by relying on the latest achievements in space medicine and human biology.

Emerging from their isolation, the crew of three Russians, one Frenchman, an Italian-Colombian and a Chinese carefully descended a metal ladder to a greeting from officials and journalists Friday.

“The international crew has completed the 520-day experiment,” team leader Alexey Sitev told Russian space officials. “The mission is accomplished. The crew is in good health and is ready for new missions.”

Organizers said each crew member will be paid about $100,000, except for the Chinese researcher, whose compensation hasn’t been revealed by officials from his country.

The crew will spend three days in quarantine before holding a news conference. They spoke to relatives and friends from behind a glass panel to minimize the risk of infection.

Sitev, who led the team into the quarters in June 2010 — just a few weeks after getting married — said he dreams of going to the beach.

“I want to go somewhere to the warm sea as we have missed two summers here,” he said in remarks carried by RIA Novosti news agency shortly before wrapping up the mission. “My thoughts are drifting toward swimming at sea and basking on warm sand.”

His Italian-Colombian crewmate Diego Urbina told RIA Novosti that he would also like to have a vacation in the Caribbean and would spend his earnings on a sports car and a pilot training course.

During the simulation, crew members were under constant surveillance and communicated with their families and space officials via the Internet, which was delayed and occasionally disrupted intentionally to imitate the effects of space travel. They showered only several times per month, pretending to conserve water. Their food was similar to what is on the International Space Station.

Midway through the mission, the crew even conducted a mock landing on a simulated Martian surface.

Scientists say that long confinement without daylight and fresh air put team members under stress as they grew increasingly tired of each other’s company.

Psychological conditions can be even more challenging on a mock mission than a real one because there is none of the euphoria or danger of space travel.

“If anything, the make-believe nature of this exercise’s goal — a simulated Mars walk — would have made it even harder psychologically than a real mission,” said James Oberg, a space consultant and NASA veteran. “So the team’s success is even more impressive, not less so, because it was ‘only a game.’ “

Oberg said he was particularly impressed with the crew’s ability to overcome the language barrier, but added that the absence of women in the experiment was a major flaw.

“Aside from the absence of physiological factors such as weightlessness and cosmic radiation, the most glaring shortcoming of this exercise was the all-male composition of the crew,” he said. “Psychological studies of frontier life and extended expeditions suggest that aside from specific skills they contribute, the presence of women in an isolated group is a positive, ‘civilizing’ effect, not a stress-inducing distracting influence.”