Should astronauts risk their health for Mars mission?
Scientists have confirmed that astronauts sent on missions to Mars would have an increased risk of developing cancer because of high levels of radiation.
The findings came from a study by Nasa's unmanned Curiosity Rover mission which counted the number of high-energy space particles striking it on its eight-month journey to the planet.
The data suggested humans would experience radiation doses that go beyond what is currently deemed acceptable for a career astronaut.
Dr Kevin Fong, a former Nasa scientist and director of the Centre for Space Medicine at University College London, said a manned mission should not be ruled out but there would be "health penalties".
Rebecca Morelle reports.