Lunar Infrared Spectrometer for detection of hydroxyl/water ice

Hydroxyl and water plays important role on tectonic process of chemical, physical, and mechanical properties of terrestrial bodies. Hydroxyl and water ice show prominent absorption features around 3 microns which is due to the stretching of O-H bond. Both VIMS (Visible and Infrared Mapping Spectrometer)/Cassini and HRI(High Resolution Imager)/Deep Impact reported that the absorption features of hydroxyl and water ice for lunar surface are appeared at 2.8 microns and 3.1 microns, respectively. In addition, M3 (Moon Mineralogy Mapper)/Chandrayaan-1 presented global distribution of the hydroxyl but unfortunately did not cover longer wavelength than 3 microns. In order to understand origin of the hydroxyl, which might be due to solar wind and/or water ice on the surface of the Moon, it is important to measure hydroxyl and water ice at the same time. We are developing Lunar Infrared Spectrometer (LIRS) for the 2nd Korea lunar mission to detect temporal variation of hydroxyl/water ice on the lunar surface. LIRS will cover from 2.0 micron to 4.0 micron at wavelength.