Future human missions to Mars will be accompanied by the Radiation Assessment Detector (RAD). RAD will be one of 10 instruments used on the Mars Curiosity rover set for touchdown on the red planet in 2012. Its goal is to monitor naturally occurring radiation that can be unhealthful if absorbed by living organisms. Unlike Mars, Earth's magnetic field and atmosphere provide shielding against the deadly effects of cosmic rays and solar particles. RAD will help scientist assess whether Curiosity's landing region on Mars has had conditions favorable for life and for preserving evidence about life.