An instrument used for broad-area imaging at high resolutions. SAR is not exclusively used in space, and is employed extensively by aircraft for environmental monitoring, Earth resource mapping, and military systems. It measures the reflection of radar pulses (emitted from the shuttle or aircraft) back from the Earth's surface. The use of radar pulses means that the mapping can take place regardless of atmospheric or light conditions. The X-band synthetic aperture radar (X-SAR) was developed by the Agenzia Spaziale Italiana (ASI; Italian Space Agency) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR; German Space Agency) for use in space as part of the Space Radar Laboratory.