] Mars radiation 'serious risk' to astronauts
]
]
] Nasa's Mars Odyssey spacecraft has confirmed suspicions
] that the radiation on Mars could endanger astronauts sent
] to explore the planet.
]
]
] Scientists say the high radiation levels also suggest any
] extraterrestrial life would have little chance of
] surviving unless it were shielded beneath the planet's
] dusty, cold surface.