Scientists at Georgetown University in Washington DC found that high energy particles in space, which are produced by solar flares, triggered an oxidative stress response in mice. Their cells generated large numbers of free radicals-- destructive molecules that can damage DNA-- which led to cancer. In the report for the research funded by NASA, scientists said the damage they observed was likely to increase the risk of colon cancer in humans.
They also found that the mice aged rapidly, turning their fur prematurely grey.
Dr Kamal Datta, who led the study, said, ''With plans for a mission to Mars, we need to understand more about the nature of radiation in space.'' People on Earth are shielded by its atmosphere, but in space there was nothing to protect astronauts from the particles, the Daily Telegraph quoted him as saying.