Mapping the moon with SIR, an infrared spectrometer for SMART-1

The infrared spectrometer, SIR, is a compact and low mass (2 kg) instrument designed to measure reflectance spectra of the lunar surface on the ESA SMART-1 spacecraft in line scanning mode. SIR offers the possibility to identify the mineralogical composition of the lunar surface to a new level of accuracy and resolution based on its superior sensitivity in the wavelength range between 900 and 2400 nm. This capability is of particular importance for the study of features like maria, craters, and fracture ridges that will provide deeper insights in crust and mantel material and therefore in the development of the Moon and the Earth-Moon system. Reflectance spectra, obtained over a large range of viewing geometries, will be useful to study their phase angle dependence and effects of space weathering.