Life on Mars? Not yet, but plans are laid for space travel after cosmic ray discovery

Humans could survive an extended visit to Mars without dying of radiation exposure, a study of the cosmic rays bombarding the Red Planet has found.

Astronauts should in future be able to shield themselves from cosmic radiation without significant increases in the risk of cancer and other radiation-induced diseases, scientists said yesterday.

Scientists are still not sure how much radiation Mars is exposed to from the Sun and other sources of cosmic rays. Unlike Earth, the Red Planet has no magnetosphere to shield it from space radiation. An experiment on board the Odyssey spacecraft orbiting Mars found that astronauts would faceradiation levels about twice those typically found on the International Space Station, which orbits within the Earth's magnetosphere.

Cary Zeitlin, a scientist at Lawrence Berkeley National Laboratory in California, said that astronauts visiting Mars would be exposed to higher risks than those spending a few months on the International Space Station. "A Mars mission would last about three years and it's the duration of the exposure that becomes the issue," Dr Zeitlin said. "We call it heavy ion radiation." Potentially, this radiation could be more damaging to health. However, it should be relatively easy to shield people from it. The Odyssey's instrument, the Martian Radiation Environment Experiment (Marie), is designed to anticipate the radiation doses in the future. One of the problems for a mission to Mars is how to carry enough fuel for life-support systems and to ensure a safe return journey. One idea is to send an unmanned probe that is able to produce oxygen and hydrogen from frozen water using solar energy.

The gases could then be used for a return journey and help to keep astronauts alive. The next space probe to reach Mars is the European Mars Express which is carrying a small, British-built lander called Beagle 2. It is due to begin its descent next week.