Underneath the oxidized red skin of Martian rocks, there is a grey Mars made of a mix of oxidized and reduced chemicals that could once have driven prokaryotic metabolisms.
The chemical analysis of rock powder from Curiosity's first drilling was released today at NASA JPL. Elements found in the material include oxygen, carbon, nitrogen, phosphorus and sulfur.
More below the fold.
Some 20% of the drilled material was clay minerals. The area where the Curiosity rover is currently located was fed by an ancient alluvial fan some 3 billion years ago.
Now that the chemical habitability of ancient Mars is established, the remainder of the Curiosity mission will look for more organic compounds in the strata of nearby Mount Sharp. After a mission pause during the upcoming conjunction of Mars with the Sun (during which communications will be interrupted) a second drilling will be done at the current location to confirm these findings. After that Curiosity will begin its long trek towards Mt Sharp.
Summary: no life was found, nor any biochemical signals of life. But the raw ingredients for life are all there, and the presence of both oxidized and reduced compounds means that chemical energy gradients which on Earth are exploited by prokaryotic metabolisms would have been present to feed Martian microorganisms during the ancient wet period. In coming months, the mission will look for clearer signals of past biochemistry.