bmahersciwriter (2955569) writes "Despite rigorous pre-flight cleaning, swabbing of the Curiosity Rover just prior to liftoff revealed some 377 strains of bacteria. 'In the lab, scientists exposed the microbes to desiccation, UV exposure, cold and pH extremes. Nearly 11% of the 377 strains survived more than one of these severe conditions. Thirty-one per cent of the resistant bacteria did not form tough, protective spore coats; the researchers suspect that they used other biochemical means of protection, such as metabolic changes.' While the risk of contaminating the red planet are unknown, knowing the types of strains that may have survived pre-flight cleaning may help rule out biological 'discoveries' if and when NASA carries out its plans to return a soil sample from Mars."