The purpose of the main experiment, expected to begin in late 2008, is to simulate a space flight to Mars taking into account all ramifications, including a 250-day "trip" to the Red Planet, a 30-day period on its surface, and a 240-day return flight.
"A crew comprising five men and one woman tested ground modules and systems in order to assess their readiness for more lengthy and realistic experiments in the future, as part of the Mars-500 project," said a spokesperson for the Russian Institute of Biological Problems, which runs the experiment.
The first test, whose participants were all Russians, was conducted on November 15-29 in life-support and medical modules at the institute's research facility.
"During the experiment, the crewmembers lived and worked in two fully isolated modules. They tested newly-designed equipment and tools used for life support, control, and communications," the spokesperson said.
Two Europeans and four Russians have been selected for the main "flight" simulation, which may last from 520 to 700 days.
During their nearly two-year isolation, crewmembers will experience many of the conditions likely to be encountered by astronauts on a real space flight.
They will adhere to a strict daily regime of work, rest and exercise, and exactly follow the diet of crews aboard the International Space Station (ISS).
The Russian scientists will conduct a second preliminary 105-day experiment in the first half of 2008.