1800	Discovery of the IR spectral region by Sir William Herschel.
1879	Use of the bolometer by Langley to make temperature measurements of electrical objects.
1889	Hertz demonstrated reflection of radio waves from solid objects.
1916	Aircraft tracked in flight by Hoffman using thermopiles to detect heat effects.
1930	Both British and Germans work on systems to locate airplanes from their thermal patterns at night.
1940	Development of incoherent radar systems by the British and United States to detect and track aircraft and ships during W.W.II.
1950's	Extensive studies of IR systems at University of Michigan and elsewhere.
1951	First concepts of a moving coherent radar system.
1953	Flight of an X-band coherent radar.
1954	Formulation of synthetic aperture concept (SAR) in radar.
1950's	Research development of SLAR and SAR systems by Motorola, Philco, Goodyear, Raytheon, and others.
1956	Kozyrev originated Frauenhofer Line Discrimination concept.
1960's	Development of various detectors which allowed building of imaging and non-imaging radiometers, scanners, spectrometers and polarimeters.
1968	Description of UV nitrogen gas laser system to simulate luminescence.