Oko

Family of Soviet and Russian early warning satellites

Oko (Old Russian: Око, lit. 'Eye') is a Russian (previously Soviet) missile defence early warning programme consisting of satellites in Molniya and geosynchronous orbits. Oko satellites are used to identify launches of ballistic missiles by detection of their engines' exhaust plume in infrared light, and complement other early warning facilities such as Voronezh, Daryal and Dnepr radars.