Astronaut Mars mission risk assessed

Nasa's Curiosity rover has confirmed what everyone has long suspected - that astronauts on a Mars mission would get a big dose of damaging radiation.

The robot counted the number of high-energy space particles striking it on its eight-month journey to the planet.

Based on this data, scientists say a human travelling to and from Mars could well be exposed to a radiation dose that breached current safety limits.

Our correspondent Jonathan Amos discussed the findings with lead researcher Dr Cary Zeitlin from the Southwest Research Institute in Boulder, Colorado, US.