HYPSOS: A HYPerspectral stereo observing system for solar system exploration

HYPSOS (Hyperspectral Stereo Observing System, patented) is a novel concept for a hyperspectral-stereo camera that combines the 3D information attainable by two stereo images, with the fine spectral sampling of a spectrograph. Planetary remote sensing represents an interesting application field for the HYPSOS concept. At the basis of HYPSOS there is the merge between two different approaches for studying the surface of a planet: the morphology of any feature analyzed by the geologist through the 3D images, and the composition of the same feature, through the hyperspectral data. In general, the merging of data provided by two different instruments may have problems due to co-registration and calibration, and the resolutions may be different requiring some interpolation. HYPSOS solves this problem by hardware: the images of the stereo channels are oriented in such a way that they are both placed along the same direction. In this way it is possible to use the same spectrometer for both channels, eventually leaving some space between the two channels to avoid signal contamination. This configuration is achieved by the placement of simple field rotating prisms along the optical paths of the two stereo-channels. A further advantage of this approach is that it does not require to limit the spectral range, which is otherwise necessary to avoid the superposition of spectra obtained by using two slits separated along track. In this paper we provide details on the configuration of the instrument, the optical layout of a possible implementation, and the resulting performances.