Hemispheric Mineralogy of the Moon: A First Look from the Moon Mineralogy Mapper (M3) on Chandrayaan-1

The Moon Mineralogy Mapper (M3) is a guest instrument on India's Chandrayaan-1 mission, which was launched October 22, 2008. M3 is an imaging spectrometer covering the wavelength range from 430 - 3000 nm, and was designed to identify and map the principal rock-forming minerals across the lunar surface. To perform initial compositional assessments, the M3 data were reduced in spatial resolution by a factor of 100 and combined into hemispheric mosaics. Initial compositional assessments reveal dramatic spectral and mineralogical diversity across the lunar surface. The spectral resolution and coverage of M3 enable identification and mapping of spectral diversity not apparent from previous data. Color composite images derived from spectral parameters that capture the full range of the 1000 and 2000 nm regions highlight the range of compositions observed in the M3 data. A range of mare basalt units are readily identified based on differences between the character of their 1000 and 2000 nm absorption features. Examples of mare basalt stratigraphy and excavation by impact craters are also clear. Fresh craters show compositional diversity quite clearly, but the advanced capabilities of M3 (spectral resolution, coverage, and uniformity) allow compositional variations in mature soils to be mapped clearly as well. In addition to diversity in mare basalts, diversity in feldspathic highlands materials is observed. A number of mafic highland craters have been imaged by M3, and these craters are spectrally quite distinct from mare basalt craters. Initial compositional assessments with M3 data provide new insight into lunar surface mineralogy at the hemispheric scale. This research is supported by the NASA Discovery Program.