Six researchers on a 520-day mock flight to Mars have finally ‘landed’ on the Red Planet.

The all-male crew – three Russians, a Frenchman, a Chinese and an Italian-Columbian – has been inside a windowless capsule at a Moscow research centre in June.

Yesterday two of the ‘astronauts’ performed a simulated spacewalk at the halfway point of their ambitious year-and-a-half isolation experiment.

It aims to test the strains on the body of travelling the solar system. It is the first full-duration simulation of a manned flight to the Red Planet.

The crew plans to complete two more extra-vehicular jaunts before next week, when the project is scheduled to begin its “return trip.”

Martin Zell, Director of ESA-ISS Scientific Program, said, “Our ambition is to have this as controlled as possible, not to have any kinds of glitches, not to have any kinds of sensational things. We just want to do a very smooth mission, a very controlled mission, and to elaborate the means of how to do a real space flight mission in the future.”

Psychologists say the long confinement will place the team members under tremendous stress especially as they grow increasingly sick of each other’s company.

Such conditions can even be more challenging during an artificial operation than a real flight, because the crew doesn’t experience any of the euphoria or dangers of actual space travel.

The idea is to closely mimic the timetable of a manned mission to Mars – 250 days for the actual journey, a month of orbiting and making surface landings, followed by a 240 day return trip back to Earth – shuttling through imaginary cosmos all the way, and totally cut off from their home world.