Mars researchers bid farewell

While the experiment, conducted jointly by Russia, China and the European Space Agency, will not involve weightlessness, it will tackle some of the psychological challenges of a real trip – particularly the stress, claustrophobia and fatigue.

The six-member, all-male crew – three Russians, a Frenchman, an Italian-Colombian and a Chinese – were confident the 520-day mission would be a success.

Diego Urbina, the Italian-Colombian member, said it would mean "accomplishing dreams about the future, doing something no human has done before."

Psychologists said the simulation could be even more demanding than a real flight because the crew will not experience any of the euphoria or dangers of actual space travel.

They have also warned the exercise will push the team to the limits of endurance as they grow increasingly tired of each other.

Based in Russia, the team is in a "spaceship" of interconnected modules and an imitator of Mars's surface for a mock landing.

The team will communicate with the "outside" world by internet – delayed and occasionally disrupted to imitate the effects of space travel.

The canned food is like that supplied to the International Space Station. The six can shower every 10 days – mimicking space conditions and they get two days off a week.