Abstract

   The visible and near-infrared imaging spectrometer (VIS-NIR) onboard the Yutu Rover collected 4 in-situ lunar reflectance spectra at a close distance (~1 meter). The onboard panorama cameras performed the first digital quantitative in-situ lunar phase curve measurement and the measured phase curve enabled us to perform an accurate photometric correction of the VIS-NIR spectra. These well-calibrated spectra have revealed less mature features than that measured remotely by the Moon Mineralogy Mapper over the same region. By using a spectral look-up-table we found the regolith at the landing site is rather olivine-rich. The mineral identification results agree reasonably well with measurements made by the onboard Alpha-Particle X-ray Spectrometer. Photometric model inversions of the phase curve enabled us to infer the size distribution, porosity and particle transparency of the regolith grains, and indicated that both shadow-hiding and coherent backscattering are responsible for the opposition surge. In addition, phase reddening effects appear to be present in the measured phase curves.