Posted: Fri, Mar 14, 2003, 8:18 AM ET (1318 GMT)
Data collected by an experiment on NASA's Mars Odyssey spacecraft shows that astronauts on any future mission to the Red Planet would be exposed to significant amounts of radiation, enough to pose a health risk. Observations by the Martian Radiation Environment Experiment (MARIE) instrument on Mars Odyssey show that astronauts on a three-year Mars mission would be exposed to about one sievert of radiation, near the lifetime limits NASA imposes on its astronauts. Those levels of radiation are about 2.5 times higher than what has been recorded on the International Space Station, which is shielded in part by the Earth itself and the planet's magnetic fields. The results were released at a briefing that marked one year of science observations by Mars Odyssey. The briefing also included discussion about mapping of the elemental and mineral composition of the planet's surface.

Related Links:

•  NASA/JPL press release
•  SPACE.com article
•  AP article
•  Florida Today article