COBE
Before leading WMAP, Bennett was the Deputy Principal Investigator for the Differential Microwave Radiometers (DMR) instrument on the Cosmic Background Explorer (COBE) mission that discovered the anisotropy of the cosmic microwave background radiation. Bennett led the effort to rebuild the radiometer front-end microwave components that succeeded in significantly enhancing the sensitivity of the DMR instrument. The Cosmic Background Explorer (COBE) Science Team also precisely measured the spectrum of the cosmic microwave background radiation.