As a defensive measure during the Cold War with the Soviet Union in the mid-1950s, the United States and Canada established the Distant Early Warning (DEW) Line of radar stations across northern Canada down to southern Alaska on the western end. Navy airborne early warning radar aircraft extended the reach farther, from Adak to Midway Atoll in the Pacific and to Iceland in the North Atlantic.
This was a continuous picket line of radar stations and aircraft with the mission to warn us of any surprise aerial attack coming over the North Pole, so that we could defend ourselves and respond in kind.
The Navy was assigned the duty of providing the overwater radar-equipped aircraft for each end of the DEW Line. The Lockheed Super Constellation civilian aircraft was modified to carry the APS 20 search radar attached to the bottom of the fuselage and the APS 45 height finder radar on top of the fuselage. Tip tanks were added to the wings to enable the aircraft to remain airborne for more than 20 hours.