Lunar and Martian soil could provide radiation shielding for crews on future space missions. Our science editor Dr David Whitehouse reports Radiation in space is bad for the health of astronauts. But no-one is certain of the best ways to protect interplanetary space crews from it. It comes from two main sources – explosions on the Sun called solar flares and from cosmic rays which are actually energetic atomic particles from deep space. The problem is not new. As early as 1952, Dr Wernher von Braun and other space pioneers suggested using lunar soil to protect a manned lunar expedition from space radiation. Scientists will soon start radiation tests using simulated Mars soil based on findings obtained about the Martian surface by the pathfinder lander than touched down last year. Designs for spacecraft to carry men to Mars, a three-year round trip, include a ‘storm shelter.’ This is a heavily shielded part of the spacecraft where the crew can hide from radiation from solar flares.