CONELRADAs a response to early Soviet atomic weapon tests, President Truman orders the initiation of the nationwide CONELRAD (Control of Electromagnetic Radiation) system, designed to limit the number of actively broadcasting radio stations whose signals could be used by enemy bombers to home in on and attack population centers. Designated AM radio stations would pass along emergency signals to smaller stations downstream, which would then begin a complex cycle of broadcasting emergency information to the public and then shutting down to allow another station to broadcast the same information; it is hoped that the rapidly shifting radio signals will prevent an invading enemy from finding viable targets. With its operating strategy assuming nuclear-armed Soviet bombers, CONELRAD will be rendered obsolete by the rise of the intercontinental ballistic missile by the end of the decade, and will be replaced by the Emergency Broadcast system in 1963.