MICRO-RAMAN FOR OFFWORLD CONSTRUCTION (MROC)

Raman spectroscopy is a powerful tool for characterization of Earth and planetary materials. There is a need for autonomous mineral and chemical characterization of the lunar regolith (LR) for in-situ resource utilization (ISRU) activities planned on the lunar surface. Development of 3D printing technology on Earth requires the use of lunar regolith simulants (LRS) as feedstock for Vitreous Material Transformation (VMX), the baseline additive manufacturing process for NASA’s Moon to Mars Planetary Autonomous Construction Technology (MMPACT) notional construction technology mission.

The µROC team, consisting of researchers at Northwestern University working in collaboration with engineers at industry partner, ICON Technology Inc., is addressing this need through a series of feasibility studies to ascertain the potential for automated visible (VIS) micro-Raman spectroscopy to characterize LRS for mineral fractions, glass content, and, importantly, Ca-content (i.e. anorthite number, An#) of the dominant plagioclase mineral to within ±2-5%, as well as hydrous impurities, all of which can strongly influence the VMX process. The test spectroscopic system for this work is a customizable breadboard spectrographic system with 458 and 785-nm excitation Raman, in-situ visible photomicrography, and reflectance or absorbance capabilities from 350-1100 nm.

The team is evaluating commercially available LRS (e.g. Exolith Labs) as well as simulants developed at Colorado School of Mines and NASA. Acquisition and data reduction routines are focused on CSM-LHT-1G and NU-LHT-5M, simulants currently used to validate VMX at ICON.