Postcards from Mars

We’re approaching the third anniversary of the Spirit and Opportunity Rover landings on Mars, and the rovers, which were expected to function for a few months at best, are still exploring the red planet and sending stunning photographs home. We’ll spend this hour with Jim Bell, the NASA scientist responsible for the rovers’ color imaging systems and author of the book “Postcards from Mars: The First Photographer on the Red Planet” (Dutton, 2006).