In “Why Curiosity Needs to Dig Deep for Organic Molecules on Mars” (Wired,
July 13, 2012), planetary science grad student Jeffrey Marlow explains,
First, the bad news: Given the model’s assumptions, organic molecules would last a mere hundreds of millions of years in the shallow subsurface of Mars. As the paper notes, “that will pose a serious challenge for organic detection by [Curiosity] since its primary focus is to look for 3.5 billion-year-old organic biomarkers while only drilling 5 cm into the surface rock.”
There is some hope, however. Radiation may be a problem for organics on Mars, but other destructive forces common on Earth don’t play a role on the Red Planet. Slow rates of erosion, a negligible hydrologic cycle, and the lack of plate tectonics all would help preserve martian organics, so if Curiosity could get below the radiation kill zone, things would be looking up.
See also: NASA inundated by ideas for exploring Mars.
Carbon from Mars not biological, study says