Colorful Views of the Moon: Comparing Spectra from Clementine and the Moon Mineral- Ogy

Introduction The Moon Mineralogy Mapper (M), which flew on India’s Chandrayaan-1 has provided the lunar science community with a richest view of our Moon to date. Information of the lunar surface returned by M provided the first conclusive evidence of the presence of OH, and possibly H2O at the poles, and in isolated locations as far down as the equator [1]. The coming discoveries and new views of our moon [see related abstracts within this conference] we owe to the vastly improved spectral resolution of the M instrument over previous lunar orbiters in particular the reining standard, Clementine’s ultravioletvisible (UVVIS) camera [2]. M’s spectral range is 4 times that of Clementine UVVIS, M’s spectral resolution (85 channels) is improved over Clementine UVVIS (5 channels), and M’s spatial resolution (∼150 m/pixel over all channels) is improved over Clementine’s (higher end at ∼125 m/pixel for the 750 nm channel and lower end at ∼250 m/pixel for the 415 nm channel). How does this improvement manifest in the data? How do M spectra compare with those from Clementine? Is it simply a matter of more detail in a spectrum? In an effort to answer some of these questions we focused on Mare Nectaris a region previously studied in detail by [3]. We used the same technique of Small Crater Rim and Ejecta Probing (SCREP) [4] to extract “fresh” spectral information from pixels that depict the rims and proximal ejecta of small, immature craters (0.5-5 km in diameter) that impacted into the mare basalt. These small craters act as windows through the ubiquitous, obscuring regolith, exposing the underlying, uncontaminated mare basalt [5, 6, 3]. Impact cratering studies and analysis of impact ejecta mechanics demonstrate that near the crater rim the original stratigraphy of the impact target is inverted [e.g., 7]. Therefore collecting data from this region provides the best approach to deriving the composition of the underlying basaltic unit [8].