VNIR is an imaging spectrometer working in the 350 divided by 1050 nm spectral range. It simultaneously acquires multiple images of the same region, each in a different narrow spectral band. The resulting images provide a spectrum for each point in the scene. The VNIR spectrometer together with an infrared channel form the instrument OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite') that will be used from a Russian orbiter to map the geochemical and mineralogical distribution of materials of the surface of Mars. The main purpose of VNIR is to extend the mapping capability towards short wavelengths, where a number of natural materials have their signatures, and to determine the location on the surface of spectral features mapped in the IR range. The instrument is composed of a lens objective and a concave holographic grating mirror based spectrometer. It can acquire images of 384 X N spatial pixels (N being the number of swaths, as the push broom technique is used) of 0.4 mrad each and 5 nm spectral resolution over 144 channels.