Scientific rationale for the D-CIXS X-ray spectrometer on board ESA'3s SMART-1 mission to the Moon

The D-CIXS X-ray spectrometer on ESA's SMART-1 mission will provide the first global coverage of the lunar surface in X-rays, providing absolute measurements of elemental abundances. The instrument will be able to detect elemental Fe, Mg, Al and Si under normal solar conditions and several other elements during solar flare events. These data will allow for advances in several areas of lunar science, including an improved estimate of the bulk composition of the Moon, detailed observations of the lateral and vertical nature of the crust, chemical observations of the maria, investigations into the lunar regolith, and mapping of potential lunar resources. In combination with information to be obtained by the other instruments on SMART-1 and the data already provided by the Clementine and Lunar Prospector has never before been utilized in spaceborne studies of atmosphereless solar system objects. The new approach could provide constraints on the local variations of particle volume fraction across the lunar surface. The volume fraction is of key importance in studies of geological evolution of the lunar regolith.