Presentation #117.03 in the session Laboratory Astrophysics (LAD) Division Meeting: The Salty Solar System I.
Regolith from the Apollo missions have been the subject of extensive laboratory analysis over the past 50 years. These studies have found a variety of silicate-based minerals and heavy metals. They have also revealed evidence of shocks due to meteorite and micrometeorite impacts and chemical processing due to the solar wind and cosmic rays. However, much of these studies provided bulk material properties and often resulted in destruction of the sample. Here, we present results from non-destructive nanoscale near-field imaging and spectroscopy using nano-FTIR (nanoscale Fourier transform infrared spectroscopy) and tip-enhanced photolumninescence of lunar regolith samples. Using the high-spatial resolution of the near-field technique in a wide spectral range, we explore gradients in mineral compositions across the grain dimension and find evidence of space weathering by comparing spectral results for space-facing and moon-facing sides of a 1 micron thick grain. The nanoscale measurements are interpreted through simulation and comparison to near-field spectra of terrestrial references. We envision wide application of the high-resolution near-field approach for hyperspectral nano-imaging of airless-body regolith from future sample return missions from asteroids, the Moon, Mercury, and Mars.