Amid much pomp and ceremony in Moscow yesterday, six carefully selected would-be astronauts began a 520-day mission to boldly go absolutely nowhere at all.
The multinational sextet, who yesterday had the doors to their small capsule sealed, will spend the next 17 months enclosed in the cylindrical mock-up spaceship, located inside a scientific institute in north Moscow.
The experiment will simulate the conditions of a flight to Mars.
Despite the fact that a real manned journey to the Red Planet is believed to be at least two decades away, the scientists organising the experiment say it will help them to understand how well human beings would cope with such a long journey in isolation.
The crew will have no access to telephones, television or any other modern luxuries, and will be able to communicate with the experiment's control room only by emails, which will have a gradually increasing time delay as the "journey" goes on and the craft "moves" further from Earth.
All food and supplies for the mission have been loaded, and nothing will go in or out for the duration of the experiment.
The six - three from Russia, one each from France and China, and one Italian-Colombian - will see no sunlight and no other people for the entire 520 days.
"Like lots of little boys, I always wanted to be an astronaut," said 31-year-old Romain Charles, a French engineer, before boarding the craft. "I kept this dream alive when I grew up so that I would have the skills if the opportunity ever came up.
"To answer the question of whether man is able to go to Mars is very exciting for me."
"Today is a celebration of science," added Igor Ushakov, director of the Institute of Biomedical Problems, the Russian institute that is leading the project. "We have been preparing for this day for many years."
The project is being run in co-operation with the European Space Agency and other international partners, notably the Chinese Astronaut Research and Training Centre, which is sending one of its trainers aboard the mission.
During the 520 days, the crew will carry out 105 experiments to determine their psychological and physical state and chart the effects of such prolonged isolation on their minds and bodies.
"We all know that this won't be an easy experiment," said Martin Zell of the European Space Agency. "But it's very important for understanding how long-distance human exploration missions into space will work. We have to learn to live in extreme environments with limited resources and communications."
The mock-up spacecraft has four modules - one containing the living quarters, one for storage, one medical module where all the scientific experiments will take place, and one "landing" module.
After the long "journey", three of the crew will emerge on to the "surface of Mars", where they will don heavy spacesuits and spend 30 days conducting experiments. The remaining three crew will stay on board the craft, supposedly orbiting the planet.
The recreation of Mars itself is a small, enclosed space with a sandy floor and a starry ceiling, and it looks rather more Red Dwarf than Red Planet. The living quarters for the crew are very simple.
Each "astronaut" has a bedroom of six square metres, with a bed, a desk, and a very small closet.
The crew's captain is Alexei Sitev, a 38-year-old Russian who has worked at Russia's Star City training cosmonauts. Recently married, he said it was not a huge problem to leave his wife for such a long period of time.
"Of course it's hard to say goodbye to your family, but many travellers who discovered new lands disappeared for long periods. They all came back, their families waited for them, so I don't see any big problems," he said.
The crew are taking plenty of reading material to keep them busy, and photographs of their families to remind them of home. Diego Urbina, the Italian-Colombian, says he hopes to read the complete works of Gabriel Garcia Marquez during the mission, while Sukhrob Kamolov, a former heart surgeon, says he is taking a medical manual in 14 parts.
Mr Urbina says he has also taken some video games, which he looks forward to playing with the other crew members.
"I've bought one of those books you always want to read but never have time for," said Charles, the French participant. "It's on art history. I never know what to think when I look at paintings, so hopefully I'll have time to read it," he joked.
The build-up to the project has not been without controversy. Some reports suggested that while the five European volunteers will all be paid 3 million roubles ($141,000) for their time in the capsule, the Chinese participant Wang Yue, put forward by the country's Space Agency, could well get much less.
When Mr Wang was asked how much he would earn for the experiment, the organisers refused to let him answer, instead assuring the assembled journalists that the crew had signed identical contracts.
The organisers hope that all six will stick out the experiment, but their contracts state that they are free to leave at any time. A spokesman for the European Space Agency said there had been 6000 applications to take part in the project.