It would take astronauts many months to get to the Red Planet
A Big Brother-style experiment to test whether humans could travel to Mars and back has begun in Moscow.
Six volunteers from Russia, France and Germany have been locked into a capsule to simulate the conditions of a manned flight to the planet lasting two years.
Those who survive more than 100 days experiencing the same isolation and claustrophobia as astronauts will earn a $20,000 (£14,000) reward.
If any of the six men get homesick, they will be allowed to come out early.
Inside the mock spacecraft, the volunteer astronauts will also have the same daily work routine and the same communication problems with mission control that real astronauts face.
Sergei Ryazansky, Russian cosmonaut
Oleg Artemyez, Russian cosmonaut
Alexei Baranov, Russian doctor
Alexei Shpakov, Russian sports physiotherapist
Cyrille Fournier, French pilot
Oliver Knickel, German engineer
That means, for example, the time delay of 20 minutes that a spacecraft near to Mars would encounter sending an astronaut's voice back to Earth.
"The experiment won't be fun but it is an honour," Sergei Ryazansky, the Russian commander of the mock spacecraft, admitted to the BBC.
Although any of the volunteers could leave if they could stand it no longer, every effort would be made to persuade them to stay for the full 105 days, he added.
"How do I feel? I am very motivated. There is a kind of relief. We have been working for a long time and finally were are getting to the start point," said Cyrille Fournier just hours before entering the capsule.
The BBC's Richard Galpin gets a sneak preview of the capsule
"The challenge is to live with the same people for a long period but it is a positive challenge. I think we are going to learn a lot about each other," his fellow volunteer, Oliver Knickel, added.
The experiment is a joint project between the Institute for Medical-Biological Problems of the Russian Academy of Sciences, and the European Space Agency.
"This is a preliminary, short experiment while the main 520-day research is scheduled to begin at the end of 2009 or the beginning of 2010," said Pavel Morgunov, a spokesman for the Moscow institute.
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