Duga (Russian: Дуга, lit. 'arc' or 'curve') was an over-the-horizon radar (OTH) system used in the Soviet Union as part of its early-warning radar network for missile defence. It operated from July 1976 to December 1989. Two operational Duga radars were deployed, with one near Chernobyl and Liubech in the Ukrainian SSR, and the other in eastern...