>The magnetic field of Mars is .1% of Earth, and its atmosphere density is 2% that of Earth, so protection from ionizing radiation would require underground hab

>The magnetic field of Mars is .1% of Earth, and its atmosphere density is 2% that of Earth, so protection from ionizing radiation would require underground habitation, the same as on Mercury. Curiosity has gathered data that suggests radiation on the surface of Mars is actually tolerable to humans [1], comparable to low-earth orbit, and presumably not too difficult to deal with for long-term surface habitation. I presume this article is a few years old due to the mention of Spirit and Opportunity but not Curiosity. [1] http://www.marssociety.org/home/press/announcements/curiositydatashowsmarssurfacecosmicrayradiationdoseacceptableforhumanexplorers http://www.marssociety.org/home/press/announcements/curiosit...