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Astrobiology Science and
Technology Instrument Development (ASTID) Laser Spectrometer for Biogenic Gases
and Isotope Ratios
Dr.
Christopher R. Webster (PI), Prof.
Geoffrey A. Blake (Co-I, Caltech), & Prof. Ken H. Nealson (Co-I, USC)
We
are funded to develop and build a miniaturized IR laser spectrometer based on combining
strengths of two separate detection techniques, laser absorption (LA) and
laser-induced fluorescence (LIF). Chemical
signatures of life will be identified through abundances of biogenic gases (disequilibrium
respired and waste products) and their C, O, N, & S isotopic ratios, since
catalytic biological reactions demonstrate a strong “preference” for lighter
isotopes, resulting in distinct isotopic fractionation between source materials
and oxidized /reduced byproducts. Direct intercomparison will be made between LA
and LIF techniques for realistic assessment of power, weight, and data rate
trade-offs. The all-solid-state LA/LIF
spectrometer will use room-temperature laser sources in both the near-IR (1-3 mm AlGaAs) and mid-IR (3-12 mm QC), and provide wide-ranging application to
measuring in situ concentrations of planetary gases such as H2O,
CO, CO2 , CH4, C2H2, HCN, C2H6,
C2N2, HC3N, O3, OCS, H2S,
and SO2, and numerous stable isotopes.