While Curiosity leads the hunt for signs of Martian life, John Matson speculates on the likelihood that earthly microbes could survive on Mars in the latest edition of Scientific American. They perhaps could be carried there by current or future space missions. NASA estimate that about 278,000 spores were carried there on the Curiosity rover alone, which is clean for a spaceship.
Engineers test how clean is Curiosity heat shield. NASA
At a recent conference held in California about habitability on Mars, Andrew Schuerger of the University of Florida indicated that three of the most hostile features of the Martian environment—low pressure, low temperature, and a carbon dioxide atmosphere without oxygen—would not prevent some Earth organisms surviving. The researchers have reported these findings in the journal Astrobiology. UV radiation due to relative lack of atmospheric ozone and the extreme dryness of the Martian environment were two other hostile factors not covered by these studies however. “Even if the UV radiation doesn’t sterilize or kill off microbes on the outside of the vehicle or on the wheels, even if the microbes are dispersed, the extreme desiccating conditions of Gale Crater argue strongly against their survival”, added Schuerger.