There are among more than 200,000 people worldwide who have signed up to take part in the Mars One space programme.

Over the next seven years, the programme will whittle that number down to just four, who will blast off in 2023 on an eight-month voyage to establish the first-ever human colony on the red planet. It would be a ONE WAY TRIP.

Critics say  :The gravity on Mars is a third that of Earth, so living there for more than a year would result in massive muscle atrophy.As a result, those selected to colonise Mars would not be able to come home because the gravity stresses upon returning could cause organ collapse.

However, the lack of gravity could also prompt increased longevity, perhaps up to 50 or 100 years beyond human averages.

To know about MARS ONE , you can read on :

http://www.mars-one.com/mission