How to put a human on Mars: The radiation threat
22 July 2013 Last updated at 15:48 BST
An Imperial College team discuss the radiation threat a human crew would face en route to Mars and on the planet itself.
They talk about the threat from the Sun and from deep space and what measures the crew could use to reduce the danger.
Video journalist: Neil Bowdler. Animation: George Spencer. Music: Spiro.