IRSUTE: a multispectral IR observation instrument on a small satellite

Satellite remote sensing measurements in the thermal IR spectrum have existed since the beginning of the space era with the first Tiros satellites in the sixties. The low spatial resolution data provided up to now have been mainly used for mesoscale applications in meteorology and oceanography. To study and understand on a local scale those natural phenomena which can be characterized by their radiative temperatures, the users need high spatial resolution data in multi-spectral channels with a good radiometric sensitivity. Thanks to recent progress in IR detector technology, these specifications will soon be satisfied. The IRSUTE (infra red satellite unit for terrestrial environment) instrument is designed to provide high spatial (50 m), multi-spectral (4 channels in the IR), high repetivity data with a good radiometric sensitivity. Moreover, the IRSUTE payload has to be compatible with the limited resources (mass, power, volume, ...) provided by a small satellite. The design of the instrument is based on the push-broom technique which uses IR-CCD linear array detectors positioned in the focal plane of a collecting telescope. The first results of a pre-feasibility study on the inboard instrument are presented.