Crew 'returns to Earth' from Mars experiment

Six volunteers from Russia and Europe were Tuesday to leave a capsule at a Moscow research facility where they have been locked up for the last three months in a bid to simulate a mission to Mars.

The four Russians and two Europeans were to emerge in front of dozens of scientists and journalists after 105 days cut off from the outside world at the isolation facility at the Russian Institute for Biomedical Problems (IBMP).

The experiment has been aimed at exactly replicating the conditions of a manned mission to Mars, including a simulated landing on the Martian surface and communication delays of up to 20 minutes.

The hatch of the simulator -- which slammed shut on March 31 -- was to swing open at 2:00 pm (1000 GMT) and the participants were then due to talk to the press alongside the project chiefs.

Scientists have been monitoring the psychological and physical effects of the prolonged isolation on the participants and are hoping this will bring a better understanding of the problems of long-term space flight.

The experiment -- a joint venture between the European Space Agency (ESA) and the IBMP -- is only the precursor to an even more daunting project planned to start in early 2010.

This will see a six member crew locked up in the same capsule but this time for 520 days, the estimated time for a return trip to Mars, ESA said in a statement.

The six have for the last three months lived in the 550 cubic metre (19,500 cubic feet) facility which has tiny individual bedrooms a maximum of 3.2 square metres (34 square feet) in area.

Their only chance to leave was if illness or other factors forced one of the volunteers to quit the experiment. All six however have made it to the end with no reports of any major problems.

The ESA and the US space agency NASA have separately sketched dates around three decades from now for a manned flight to Mars.

The Red Planet's distance from Earth varies between 55 million kilometres (34 million miles) and more than 400 million kilometres (250 million miles).