L3VIN: LUNAR-LASER-LAB FOR VOLATILES INVESTIGATION. AN IN-SITU INSTRUMENT FOR SMALL ROVERS AND LANDERS

Lunar-Laser-Lab for Volatiles Investigation (L3VIN) is a laser-induced breakdown spectroscopy (LIBS) instrument under development that incorporates spatial mapping and imaging optical assemblies into a compact package that can be integrated into small rovers or landers to enable geochemical investigations on natural unprepared samples, such as regolith and rocks. The novel benefit of L3VIN is the ability to acquire 2D raster LIBS from a standoff distance across natural surfaces. Combined with a near-infrared reflectance instrument, L3VIN would enable geochemical and mineralogical information to be obtained from the same spot on the lunar regolith, providing ground-truth characterization and information regarding the distribution of lunar materials (hydrated/hydrous compounds, minerals, metals, and volatiles) in locations of high interest in the south polar region and the Gruithuisen Domes.

To demonstrate the utility of L3VIN for a lunar application, six lunar analog materials were analyzed: serpentine, diorite gneiss, granite, basalt and ferrihydrite standard samples, and a well-known lunar analog JSC-1 (regolith) due to their strong correlation to lunar regolith chemistry and suite of elements of interest more broadly.

Differentiation in the weight percent (wt%) of elements, i.e., titanium, can help to determine the approximate age and formation process of mare basalts. Our instrument has demonstrated the ability to detect Ti as indicated by the regolith, basalt, and granite spectra. Moreover, lunar regolith is typically very rich in Ca (i.e., diorite gneiss/regolith) and deficient in alkali metals such as Na, K, and Rb apart from KREEP rocks (i.e., those enriched in K, rare earth elements, and P. The sensitivity of our detector was quantified with a 4.5 wt% Si in Ca solid solution where the Si peak was detected well above the noise floor, indicating the ability to detect Si at lower concentrations.