Radiance Contrasts at Possible Lunar Water Ice Exposures Seen by ShadowCam

Since 2023 January, ShadowCam, a single-band visible camera aboard the Korean Pathfinder Lunar Orbiter (KPLO), has been imaging northern and southern polar PSRs with 200 times the sensitivity of the LROC NAC (SNR > 100 for radiance > 0.12 W m −2 Sr −1 μm −1 ) and small pixel scales (∼1.7 m pixel −1 ) and was hypothesized to enable water ice detection using visible wavelengths (D. C. Humm et al. 2023 ; M. S. Robinson et al. 2023 ). Using ShadowCam maximum radiance mosaics, we assess whether or not the M 3 surface water ice detections from S. Li et al. ( 2018 ) correlate with any enhanced radiance contrasts attributable to water ice. We searched for these radiance contrasts in both northern and southern polar PSRs that vary in age, location, and amount of ice detections by M 3 . At visible wavelengths, fine-grained (∼70 μm) pure water ice at lunar temperatures (∼70–150 K) has a reflectance close to ∼1 (R. N. Clark 1981 ; K. Stephan et al. 2021 ). This makes ice significantly brighter th ... Read full article.