Remote sensing for organics on Mars.

The detection of organics on Mars remains an important scientific objective. Advances in instrumentation and laboratory techniques provide new insight into the lower level detection limit of complex organics in closely packed media. Preliminary results demonstrate that algae present in a palagonite medium do exhibit a spectral reflectance feature in the visible range for dry mass weight ratios of algae to palagonite greater than 6%--which corresponds to 30 mg algae in a 470 mg (just optically thick (< 3 mm) layer) palagonite matrix. This signature most probably represents chlorophyll a, a light harvesting pigment with an emission peak at 678 nm.