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Abstract Pulsed‐laser irradiation causes the visible‐near‐infrared spectral slope of olivine (Fo₉₀and Fo₉₉₊) and SiO₂to increase (redden), while the olivine samples darken and the SiO₂samples brighten slightly.XPSanalysis shows that irradiation of Fo₉₀produces metallic Fe. AnalyticalSEMandTEMmeasurements confirm that reddening in the Fo₉₀olivine samples correlates with the production of “nanophase” metallic Fe (npFe⁰) grains, 20–50 nm in size. The reddening observed in the SiO₂sample is consistent with the formation of SiO or other SiO_xspecies that absorb in the visible. The weak spectral brightening induced by laser irradiation of SiO₂is consistent with a change in surface topography of the sample. The darkening observed in the olivine samples is likely caused by the formation of larger npFe⁰particles, such as the 100–400 nm diameter npFe⁰identified during ourTEManalysis of Fo₉₀samples. The Fo₉₀reflectance spectra are qualitatively similar to those in previous experiments suggesting that in all cases formation of npFe⁰is causing the spectral alteration. Finally, we find that the accumulation of successive laser pulses cause continued sample darkening in the Vis‐NIR, which suggests that repeated surface impacts are an efficient way to darken airless body surfaces. 

The lunar exosphere is generated by a variety of processes: photodesorption from solar UV radiation (PSD), solar wind ion sputtering, meteoritic bombardment, radioactive decay, and thermal desorption. While remote or orbital temporal measurements provide in situ clues to source mechanisms, individual ejection processes are more easily and deeply investigated in laboratory experiments on returned Apollo samples and analogs, allowing quantitative comparisons at lunar-like pressures and temperature. The importance of laboratory experiments cannot be overemphasized, providing measurements of ejection probabilities relevant to exospheric formation, as well as metrics such as surface charge, surface composition and phase, and meteoritic-impact plume characterization. These parameters can be convolved to describe telescopic observations as well as phenomena observed at the lunar surface by orbital / lander measurements, providing ground truth for models of spatial and temporal variations in the exosphere. The following discussion of laboratory work pertinent to the generation of the lunar atmosphere is a starting point for those interested in laboratory simulations and is by no means an exhaustive review.