Istrebitel Sputnik, or IS ( meaning Satellite Fighter, after the meaning "Fighter aircraft" for the Russian word istrebitel), was a Soviet anti-satellite weapons programme which led to the deployment of the IS-A or I2P system during the 1970s and 1980s. IS satellites were originally intended to launch on UR-200 rockets, but following the cancellation of the UR-200, the Polyot, Tsyklon-2A and Tsyklon-2 rockets were used instead.