A Compact, Dual Excitation Raman Probe and Instrument for the Identification of Lunar Samples

NASA's Vision for Space Exploration advocates a return to the moon and involves a plan of using the moon as a base of for missions to other planets. Early return missions to the moon will involve lunar exploration with robotic spacecrafts with instrumental payloads for scientific measurements of lunar surface features such as rocks, soil, and minerals. These instrument payloads will be helpful in identifying lunar resources that can be used in establishing extended human presence. Raman spectroscopy has been actively investigated as a lunar as well as a Mars surface robotic investigative tool for minerals. Current Raman instruments for space exploration utilize a single excitation wavelength, with a laser in the near-infrared (IR) to minimize fluorescence background. However, even with the near-IR Raman excitation, background emissions such as fluorescence, F-center luminescence, and blackbody emission can still be a problem. The goal of this project is to employ a dual excitation (visible and near-IR lasers) Raman instrument to minimize background emission. To achieve this goal, a dual excitation wavelength fiber optically coupled Raman probe head and a compact wide spectral range echelle spectrograph will be developed.