NASA's Mars Odyssey spacecraft has confirmed suspicions that the radiation on Mars is so intense that it could endanger astronauts sent to explore the Red Planet, scientists said Thursday.

　　The high radiation levels measured by the robotic probe also suggest any extraterrestrial life that might call the planet home would have little chance of surviving unless it were shielded beneath the planet's dusty, cold surface, said Cary Zeitlin of the National Space Biomedical Research Institute in Houston.