Like a human working in a radiation environment, NASA's
Curiosity rover carries its own version of a dosimeter to
measure radiation from outer space and the sun. This graphic
shows the flux of radiation detected by Curiosity's Radiation
Assessment Detector (RAD) on Mars over three and a half hours on
Aug. 6 PDT (Aug. 7 UTC). The data show that the radiation levels
measured on Mars during this period of quiet solar activity are
reduced from the average radiation detected in space during
Curiosity's cruise to Mars. This is explained by the rover being
on the planet versus out in space, where it would have more
exposure to radiation from all directions. Red arrows point to
spikes in the radiation dose rate from heavy ion particles,
which would be the most dangerous to astronauts. During the
course of the mission, scientists will study the variation of
the radiation levels as a function of solar activity to
understand and model the effects of the Martian atmosphere on
radiation dose rates. Scientists and engineer