Sentinel-2 MultiSpectral imager (MSI) and calibration/validation

In the frame of the Global Monitoring for Environment and Security programme (GMES) jointly implemented by ESA and EC, ESA is developing the Sentinel-2 system, providing globally with systematic acquisition high resolution optical observations with a high revisit tailored towards the needs of operational land services. This system will ensure data continuity of multi-spectral imagery provided by the SPOT series of satellites and further enhancement to account of future service evolution. During full operations two identical satellites will be operated. Each satellite embarks the MultiSpectral Instrument (MSI) that is a push-broom imager providing imagery in 13 spectral channels with spatial resolutions ranging from 10 m to 60 m and a swath width of 290 Km, larger than SPOT and Landsat. The instrument features a sun diffuser covering the full field of view for radiometric calibration, a silicon carbide Three Mirror Anastigmat telescope, specific filter stripe assemblies, newly developed Si-CMOS and HgCdTe detectors and a low noise wavelet compression video electronics. Most of the flight models of the equipments have been delivered and the focal planes and telescope of the MSI Protoflight Model are under assembly, integration and testing. A thorough on-ground characterization of the MSI will be performed to pave the way for the in-flight calibration/validation that will be performed during the commissioning phase. The launch of Sentinel-2A is foreseen in 2013. This paper provides an overview of the GMES Sentinel-2 Instrument including a technical concept overview, Instrument performance on-ground characterization and approach for the in-orbit calibration/validation during the commissioning phase.