Well, they're off: six trained astronauts on a 520 day mission to... Moscow.
ESA's simulated Mars mission is now underway, as the volunteers today shut themselves into the Mars500 isolation project.
The six guinea-pigs - Diego Urbina and Romain Charles from Europe, Sukhrob Kamolov, Alexey Sitev, Alexandr Smoleevskiy and Mikhail Sinelnikov from Russia and Wang Yue from China - will live a life as close as possible to that which would be experienced by true Martian astronauts.
They've been through all the standard selection procedures. "I was not aware that such a quantity of medical tests could be performed on a human being. I was happy to know that I didn't have any obscure disease that could only be diagnosed with a giant €3 million machine!," says Urbina.
The astronauts' mission is to 'fly to Mars' over the next 250 days, 'land and explore' for 40 days and then 'return to Earth' in 230 days.
Bet they wish those inverted commas weren't there.
The hatch will remain closed until November next year, and the crew will have to manage using only the stored food and equipment. One hopes they won't be reduced to eating each other.
Only electricity, water and some air will be fed into the compartments from outside.
"Staying almost 18 months inside the metallic containers will be hard, even when properly trained and briefed by astronauts and submariners," says ESA. "The crew will no doubt have ups and downs during their long mission and these psychological changes are a key part of the experiment."
The 'astronauts' will work eight hours a day, with the weekends free, and have taken plenty of films, books, games, musical instruments and entertainment with them.
They can exercise up to two hours a day, but will shower only once a week, lending new meaning to the words 'alien atmosphere'.
Outside help will be given only in extreme situations, says ESA.
Throughout their mission, Urbina and Charles will send diary updates and videos to ESA’s Mars500 site.