The search for ancient life on Mars and the IR spectroscopy of Earth analogues.

One of the main aims of the next Mars space missions will be to characterize biochemically the surface and underground of the planet in the search for elementary forms of life. Laboratory analyses devoted to the study of techniques able to recognize the biological origin of samples, carried out on Earth analogues of Martian ground, are fundamental support for the planning of suitable instrumentation and the subsequent analyses of data. Here we present the results of infrared transmission spectroscopic studies on old biological carbonates with different degrees of degradation, including carbonates linked to primitive terrestrial living organisms (fossil stromatolites), performed to evidence spectroscopic peculiarities and their likely dependence on the age of formation. We also report preliminary measurements using reflectance spectroscopy, a technique more likely to be performed directly in situ on the surface of Mars.