After months sealed in an isolation chamber, participants in a simulated mission to Mars emerged into a muggy Moscow afternoon on Tuesday, completing what international scientists hope is a small step toward a staffed mission to the red planet. The six participants — four Russians, a German soldier and a French airline pilot — spent 105 days locked in a series of hermetically sealed tubes as part of the Mars-500 project at the Institute of Biomedical Problems here. An actual staffed mission, if one occurs, could be decades off, but Russian scientists and officials said the Mars-500 project, which will culminate in a 520-day isolation experiment scheduled to start next year, was an indication of Russia’s revitalized role in space exploration after years of struggling to keep a foothold in orbit. “At this time we are moving from the era of preserving Russia’s place in space to its advancement,” Vitaly A. Davydov, the deputy chief of the Russian Federal Space Agency, said at a news conference. “This is a promising project that will guarantee the orbital deployment of equipment that will fly to the moon and Mars.” The Mars-500 crew conducted about 70 experiments, testing psychological and physical reactions to long-term isolation similar to that expected during interplanetary space travel. A real mission to Mars would last more than 500 cramped, lonely days, most of which would be spent in transit. Adding to the isolation are communication delays with Earth that last up to 20 minutes. The international team of scientists drawn from Europe and the United States involved with Mars-500 is seeking ways to avoid the mental breakdowns or worse that could result from such prolonged monotony in part simply by locking people into the Soviet-era isolation chamber and observing what happens. “From day to day, the work did not stop for a second,” Aleksei V. Baranov, the mission physician, said after the crew was let out. “In those minutes when you could relax, you remembered that you were not at home, that you were far from your loved ones, that every day you were supposed to wake up early and work, work, work,” he said. “This is difficult to be psychologically prepared for: unceasing, monotonous work.” Crew members said that tensions were at times unavoidable, though no major conflicts occurred. Project organizers, meanwhile, declared the mission an overall success, but said detailed results from the experiment would be available only after several weeks of analysis. “The results of this experiment show that the basic principles on which we based this experiment were proven correct,” said Boris V. Morukov, the experiment’s director and a former crew member on the International Space Station.