about 400–500mSv/a. JPL reported that MARIE-measured radiation levels were two to three times greater than that at the International Space Station (which is 100–200 mSv/a). The levels at the Martian surface might be closer to the level at the ISS due to atmospheric shielding – ignoring the effect of thermal neutrons induced by GCR. References External links NASA's site on MARIE 2001 Mars Odyssey Spacecraft instruments Missions to Mars Cosmic rays