BBC A team of Nasa recruits has begun living in a dome near a barren volcano in Hawaii to simulate what life would be like on Mars.
'The isolation experience, which will last a year starting on Friday, will be the longest of its type attempted.
'Experts estimate that a human mission to the Red Planet could take between one and three years.
'The six-strong team will live in close quarters under the dome, without fresh air, fresh food or privacy.
'They closed themselves away at 15:00 local time on Friday (01:00 GMT Saturday).
'A journey outside the dome - which measures only 36ft (11m) in diameter and is 20ft (6m) tall - will require a spacesuit.
French astrobiologist, a German physicist and four Americans - a pilot,
an architect, a journalist and a soil scientist - make up the Nasa