Nasa weighs up Mars stress factor

Nasa's view of the approach to the Martian surface (Courtesy of Nasa animation)

Nasa scientists, encouraged by the success of the Mars Pathfinder mission and finding water on the Moon, are stepping up plans to send the first manned mission to the Red Planet.

Teams of aspiring Mars astronauts have spent 60 days in "deep isolation", sealed inside a steel capsule at Nasa's Johnson Space Centre in Houston,Texas, in order to test human endurance for such a flight.

The space agency has made an animated film to promote its aim to send a manned mission to the planet by 2014. It is now trying to raise funding from the American government.

'Biggest space challenge yet'

Unlike robots, astronauts who land on Mars would be at risk from deadly cosmic rays

Scientists said the mission would be the biggest challenge so far in mankind's brief history in space. However, according to a BBC Correspondent, they are worried that it could be beyond human endurance.

Such a mission could last up to four years with astronauts cramped together in stressful conditions.

"It's not going to be an easy trip. It's going to be the biggest engineering challenge we've ever undertaken," said Nasa scientist, John Connelly.

"The trip out is going to be a six-month trip in zero gravity. Once we get to Mars we'll be there for 500 days while the Earth and Mars travel round the Sun and come back into the right position to come back to Earth.

"Then it's another six-month trip back."

Sealed in steel

One of the Mars astronaut guinea-pigs hugs her colleague after emerging from isolation

Teams of four trainee astronauts have already spent 60 days sealed inside the steel capsule at the space centre in Texas. The capsule aims to simulate likely conditions on a Mars trip.

Nasa crews are learning how to grow their own food and recycle waste. However, as well as work duties, they are also learning how to cope with stress and relax.

"For me, I like to listen to music," said Fred Smith, one of the trainee astronauts who spent time inside the test capsule. "But we also have a personal space upstairs where we can go and close the door and kind of isolate ourselves if we need some down time."

Stress on Mir

Pathfinder made a number of important discoveries about Mars

His colleague, Karen Myers, said: "We had support from the site team on the outside. If we needed them at any time we could talk to them and maybe get another opinion about how to handle the situation."

Stress is said to have taken its toll on the Russian space station Mir, with rows and personality clashes among the crews.

The test for Nasa will be to prove that Mars astronauts could spend up to four years in a capsule like the simulator without sacrificing their physical and mental health.