Vesta, the second largest object in the main asteroid belt of our Solar System, was explored by the NASA Dawn mission for over one year in 2011-2012. Dawn is equipped with the Framing Camera (FC), which provides geological and compositional analysis, the Visible and InfraRed (VIR) mapping spectrometer, which allowed a comprehensive mineralogical mapping of the surface, and the Gamma Ray and Neutron Detector (GRaND), which reveals the elemental composition. A wealth of data acquired by these three instruments allowed for improving the knowledge on the surface and near-surface properties of Vesta.

Based on VIR data acquired in the overall spectral range 0.25-5.1 µm at spatial scales ranging from tens of meters to tens of kilometers, the overall mineralogy of Vesta is consistent with howardite–eucrite–diogenite (HED) meteorites. More specifically, VIR spectra are consistent with a surface covered by a howardite-like regolith containing various proportions of eucrite and diogenite at different locations. Diogenite shows up in localized regions and mostly occurs in the southern polar region within the Rheasilvia impact basin.

I will present an overview of the main scientific results obtained by the VIR instrument at Vesta, both at regional scale and local scale. From March 2015 onwards, the Dawn spacecraft is exploring its other major target, the dwarf planet Ceres. Here the hyperspectral images returned by VIR have already been able to provide important clues about the overall mineralogy.