In situ investigation of ices and hydrous minerals at the lunar poles using a combined X-ray fluorescence and diffraction instrument

There is a growing body of evidence that points to the survival of water or hydrous minerals on the Moon and the potential for large aqueous reservoir s in shadowed craters at the lunar poles. CheMin, an XRD/XRF instrument tha t is currently under development, could provide a definitive test of whethe r the polar hydrogen signal measured by the recent Lunar Prospector mission is an indication of a significant water reservoir or merely reflects an an omalously rich accumulation of solar-wind hydrogen. Proposed enhancements o f CheMin could be used in conjunction with a drilling system capable of pen etrating the upper few tens of centimeters of the lunar regolith to search for ices or hydrous minerals. This advanced version of the CheMin instrumen t would be within the size, mass, and power constraints of Ariane 5 micromi ssions.