PRISM: Hyperspectral spaceborne imager for land processes research

For the post 2000 time frame, the European Space Agency (ESA) has defined candidate missions for Earth Observation. In the class of the Earth Explorer missions, dedicated to research and demonstration missions, the Land-Surface Processes and Interactions Mission (LSPIM) involves a dedicated satellite carrying a single optical payload named PRISM (Processes Research by an Imaging Space Mission). PRISM is a push broom multispectral imager providing high spatial resolution images (50 m over 50 km swath) in the whole optical spectral domain (from 450 nm to 2.3 mu m with a resolution close to 10 nm, and three bands from 8 to 12.3 mu m). It provides an access on any site on Earth within at maximum 3 days. In addition, the mission will be able to provide multi-directional observations by combining instrument depointing capabilities and satellite manoeuvring. The instrument radiometric performance reach a high level of accuracy by involving on-board calibration capabilities. This paper presents the results of one of the two pre-feasibility studies awarded by ESA, led by AEROSPATIALE and concerning the PRISM payload.