Low-Frequency Dielectric Spectroscopy of Martian Soil Samples / 73-76
John H. Miller, Jr., Jaroslaw Wosik, David S. McKay, David Warmflash
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Abstract--Martian soil simulants and live cell suspensions are under study using low-frequency dielectric spectroscopy (DS) and related techniques, such as nonlinear harmonic response. Such methods hold tremendous potential to develop sensors that can test for subsurface microbial life on Mars and for numerous additional applications. For example, the low-frequency alpha-dispersion, unique to live organisms, leads to enormous dielectric responses that enable a clear distinction between living and inanimate materials. UH researchers measured the low-frequency dielectric properties of soil samples known to be Mars analogues, as well as known live cell suspensions. In this initial study, they tested common soil and JSC Mars-1, a volcanic ash from Hawaii developed for use as a Mars regolith simulant. Biologically active, JSC Mars-1 contains microorganisms and biomolecules equivalent to 10⁶-10⁷ cells/gram, less than common soils. Finally, the UH research team recently discovered resonant-like behavior in the frequency-dependent harmonic responses of live cells. Preliminary evidence suggests that this behavior may result from active molecular motor complexes unique to live organisms. DS may prove to be a life detection tool.