The Moon Mineralogy Mapper (M³) imaging spectrometer for lunar science: Instrument description, calibration, on-orbit measurements, science data calibration and on-orbit validation

Abstract

[1] The NASA Discovery Moon Mineralogy Mapper imaging spectrometer was selected to pursue a wide range of science objectives requiring measurement of composition at fine spatial scales over the full lunar surface. To pursue these objectives, a broad spectral range imaging spectrometer with high uniformity and high signal-to-noise ratio capable of measuring compositionally diagnostic spectral absorption features from a wide variety of known and possible lunar materials was required. For this purpose the Moon Mineralogy Mapper imaging spectrometer was designed and developed that measures the spectral range from 430 to 3000 nm with 10 nm spectral sampling through a 24 degree field of view with 0.7 milliradian spatial sampling. The instrument has a signal-to-noise ratio of greater than 400 for the specified equatorial reference radiance and greater than 100 for the polar reference radiance. The spectral cross-track uniformity is >90% and spectral instantaneous field-of-view uniformity is >90%. The Moon Mineralogy Mapper was launched on Chandrayaan-1 on the 22nd of October. On the 18th of November 2008 the Moon Mineralogy Mapper was turned on and collected a first light data set within 24 h. During this early checkout period and throughout the mission the spacecraft thermal environment and orbital parameters varied more than expected and placed operational and data quality constraints on the measurements. On the 29th of August 2009, spacecraft communication was lost. Over the course of the flight mission 1542 downlinked data sets were acquired that provide coverage of more than 95% of the lunar surface. An end-to-end science data calibration system was developed and all measurements have been passed through this system and delivered to the Planetary Data System (PDS.NASA.GOV). An extensive effort has been undertaken by the science team to validate the Moon Mineralogy Mapper science measurements in the context of the mission objectives. A focused spectral, radiometric, spatial, and uniformity validation effort has been pursued

Lunar cryptomaria: Mineralogy and composition of ancient volcanic deposits

“…Variation in absorption band center due to the continuum removal process has been previously noted (Clenet et al, 2011). Klima et al's (2007Klima et al's ( , 2011 laboratory spectra of the synthetic pyroxenes were measured from 0.45 to 2.6 μm; in many cases, the entire 2 μm absorption band was not measured which, in our continuum removal process and MGM modeling, shifts the band center of the 2 μm absorption features to shorter wavelengths (Fig. 4).…”

“…M 3 was a VNIR imaging spectrometer aboard the Chandrayaan-1 spacecraft that collected mineralogic information about the Moon's surface in 85 bands, from approximately 0.4-3.0 μm, at a spatial resolution of 140-280 m/pixel, depending on the spacecraft altitude (Pieters et al, 2009;Green et al, 2011). All spectra examined in this study were collected from M 3 mosaics composed of individual data strips (Table S3) and have a spatial resolution of 140 m/pixel.…”

“…All of the VNIR spectra used in this study were collected from the Moon Mineralogy Mapper (M 3 ) dataset Clark et al, 2011;Green et al, 2011;Besse et al, 2013). M 3 was a VNIR imaging spectrometer aboard the Chandrayaan-1 spacecraft that collected mineralogic information about the Moon's surface in 85 bands, from approximately 0.4-3.0 μm, at a spatial resolution of 140-280 m/pixel, depending on the spacecraft altitude (Pieters et al, 2009;Green et al, 2011).…”

Measuring moonlight: An overview of the spatial properties, lunar coverage, selenolocation, and related Level 1B products of the Moon Mineralogy Mapper

“…Contact with the spacecraft was lost prematurely on 29 August 2009 after almost a 10 month mission. Despite the difficulties and shortened mission Chandrayaan-1 was able to collect data with all instruments and to meet the majority of its baseline mission goals [Green et al, 2011].…”

“…Our goal is to document and describe the spatial aspects of the instrument, the mission and the observed data and their processing via an optimized pixel-by-pixel ray tracing and the resulting data products. A companion paper [Green et al, 2011] provides more information regarding the instrument design and construction and its spectral and radiometric characteristics and calibration.…”