Artist's impression of COBE, NASA's Cosmic Background Explorer satellite. Launched on 18 November, 1989, COBE is a fundamental space astronomy mission designed to investigate the cosmic background radiation & answer questions about the expansion & nature of the Universe as a whole. It is equipped with infrared & microwave sensors which will map the whole sky at 100 different wavelengths. In 1990, COBE returned the first spectrum of the cosmic background radiation, the heat signal" of the Big Bang, & showed it to be a perfect "black body" curve, thus confirming at a stroke the theory of the Big Bang."