Synthetic Aperture Radar (SAR) satellites utilise the vantage point offered from low earth orbits to provide day, night and all-weather global surveillance to support a wide range of military requirements. Surveillance from space is non-intrusive and can provide timely observation of any point on the earth's surface, especially when several satellites are configured into a constellation. The SAR capability, together with other space-based assets, can help to provide both a strategic and tactical capability to the military operational Commander Matra Marconi Space is at the forefront of SAR design and manufacture cmd has been responsible for both of the European SAR missions: ERS - AMI and ENVISAT - ASAR. This has allowed the evolution into innovative designs described in the paper which are now available to meet the new emerging requirements.