SAR-Lupe is Germany's first reconnaissance satellite system. SAR is an abbreviation for Synthetic Aperture Radar and "Lupe" is German for magnifying glass. The SAR-Lupe program consists of five identical (720kg) satellites, developed by the German aeronautics company OHB-System, and one ground station at the Zentrum für Nachrichtenwesen der Bundeswehr (ZNBw), Max-Planck-Str. 17, 53501 Gelsdorf 50°34′06″N7°02′11″E / 50.5683, 7.0363 which is responsible for controlling the system and analysing the retrieved data. A large data archive of images will be kept in a former Cold Warbunker belonging to the ZNBw. SAR-Lupe's "high-resolution" images can be acquired day or night though all weather conditions. The first satellite was launched from Plesetsk on 19 December2006, about a year after the intended launch date; further satellites will be launched at roughly six-month intervals, and the entire system will be fully operational by 2008. The five satellites operate in three 500-kilometre orbits in planes roughly sixty degrees apart. They use an X-band radar with a three-metre dish, providing a resolution of about 50 centimetres over a frame size of 5.5km on a side ('spotlight mode', in which the satellite rotates to keep the dish pointed at a single target) or about one metre over a frame size of 8km x 60km ('stripmap mode', in which the satellite maintains a fixed orientation over the earth and the radar image is formed simply by the satellite's motion along its orbit). Response time for imaging of a given area is ten hours or less. Thales Alenia Space provided the core of the Synthetic Aperture Radar sensors.[1] The testing of SAR-Lupe involved an inverse procedure, in which the satellite, mounted in a radome on Earth, was used to image the International Space Station, whose orbit is reasonably close to the one the satellite will eventually be in. One-metre resolution at the ISS was apparently achieved. On 30 July2002 a cooperation treaty between Germany and France was signed, under which the SAR-Lupe satellites and the French Helios optical reconnaissance satellite will operate jointly. Other EU countries have been invited to join as well and Italy has shown considerable interest.
