Free SSB resources for those interested in Mars
The following authorative and excellent books are free to read online from the NAS:
Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface
http://www.nap.edu/catalog/10360.html
Safe Passage: Astronaut Care for Exploration Missions
http://www.nap.edu/catalog/10218.html
The Quarantine and Certification of Martian Samples
http://www.nap.edu/catalog/10138.html
