NASA's Mars rover Curiosity will touch down on August 5 and there is anticipation building that the machine will be able to detect signs of life where previous efforts have failed.
Evidence of ancient life on Mars, if any such evidence exists, might be detectable at shallower depths below the planet's surface than has been thought, a new study says - which would improve the chances that NASA's newest Mars rover, scheduled to touch down on the Red Planet next month, finds it.
The research indicates that simple organic molecules, such as a single molecule of formaldehyde, could exist a mere 2 to 4 inches beneath the Martian surface. While the radiation level at these depths is still intense, simple building blocks of life (and, in the case of young craters, perhaps even complex building blocks) could survive, the researchers said.
The study, which suggests ideal locations and depths to search for organic molecules, could act as a road map for the Curiosity rover, which is due to land on Mars the night of Aug. 5.
Once on the surface, Curiosity, carrying out NASA's Mars Science Laboratory mission, is expected to dig, drill and investigate rocks for signs that Mars is, or ever was, inhabited.
"Right now the challenge is that past Martian landers haven't seen any organic material whatsoever," study lead author Alexander Pavlov, of NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement. "We know that organic molecules have to be there, but we can't find any of them in the soil."
The researchers report that the chances of finding organic molecules roughly 0.8 inches below the surface are close to zero. The top layer of the Martian surface has absorbed so much cosmic radiation over the past billion years that all organic material is likely to have been destroyed, the scientists said. Past rovers on Mars collected and analyzed only loose soil from the topmost layer of the Martian surface.
Yet only inches deeper -- within reach of Curiosity -- simple organic molecules could still exist, the researchers said.
Costing $2.5 billion, Curiosity is likely to be the last rover for a while. Budget cuts have nixed 2 other Mars missions and funding is unlikely to be restored.