A CRDS for Isotopic Measurement of Martian CH4
T.C. Onstott, Dept. of Geosciences, Princeton University, Princeton NJ 08544
K. K. Lehmann, Dept. of Chemistry and Physics, Univ. of Virginia, Charlottesville, VA
P. R. Mahaffy, NASA Goddard, Code 699, Greenbelt, MD 20771
Project URL: http://www.princeton.edu/southafrica/mars/
The scope of this NASA Astrobiology Science and Technology Instrument Development, ASTID, funded project is to flight-qualify a near-IR CRDS that is capable of determining the C and H isotopic composition of the atmospheric CH4 on Mars with an accuracy comparable to that given by isotope ratio mass spectrometry. A space flight version of a Cavity Ringdown Spectrometer, CRDS, is being built at Goddard Space Flight Center (GFSC) by the Mahaffy group. Its design is based upon that of a by near-IR CRDS at Princeton University (P.U.). The near-IR CRDS at Princeton University is being used to test the circuitry and software requirements for rapid and precise isotopic measurements and the design requirements are then transferred to the Goddard CRDS. The Princeton University instrument is also being adapted to applications on Earth and has been field tested in the high Canadian Arctic. The near-IR CRDS at the University of Virginia (UVa) is being used to determine the line strengths of CH3D as a function of temperature and pressure and gas composition as this data does not exist in the HITRAN database and will be essential for interpreting data from Mars and the Earth.