The Cosmic Background Explorer (COBE) satellite was developed by NASA's Goddard Space Flight Center to measure the diffuse IR and microwave radiation from the early universe, to the limits set by our astrophysical environment. It was launched 18 November 1989 and carried three instruments, a FIR Absolute Spectrophotometer (FIRAS) to compare the cosmic microwave background radiation with a precise blackbody, a Differential Microwave Radiometer (DMR) to map the cosmic radiation precisely, and a Diffuse Infrared Background Experiment (DIRBE) to search for the accumulated light of primeval galaxies. The cosmic microwave background radiation spectrum was measured 1000 times more precisely than was possible before the COBE launch. The microwave background was found to have an intrinsic anisotropy for the first time, at a level of a part in 105 with a smoothing of 10°. A comprehensive set of absolutely calibrated IR sky maps has been acquired to search for the cosmic IR background.