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SAR evolution and user needs in the post-Envisat time frame

The ENVISAT-1 mission should extend its operational lifetime to 2003-2004, completing nearly 15 years of continuous availability of data from spaceborne synthetic aperture radars. This paper intends to review the perspectives, in terms of sensor characteristics, operating strategy, synergic options and user requirements, for the following generation of such instruments from two points of view: a) the need to continue to support Earth science research in the microwave domain; b) the need to ensure data continuity for those operational applications which have been proven in the course of the previous missions and which rely on the continuous availability of SAR data, among others.