of its intercontinental bombers closer to the Soviet Union for possible attacks over the Arctic. The first use of Eielson was by the SAC 97th Bombardment Group, deployed from Smoky Hill AAB, Kansas in November 1947. The group departed in March 1948, with the 5010th Air Base Wing being activated by AAC as a permanent host unit for Eielson, supporting deployed SAC units from the CONUS. Other SAC units followed and Eielson hosted B-29, B-36, B-47 and B-50 wings, which were placed on alert there and ready to strike on a moment's notice. These deployments lasted until 1963. Eielson also hosted deployed KC-97s, and later KC-135s tanker aircraft. SAC activated its provisional 4157th Combat Support Group (later Strategic Wing) at Eielson in July 1956 to support additional B-47 Wing deployments to Alaska in addition to 4158th Strategic Wing to support RC-135 electronic intelligence (ELINT) operations from Elmendorf on 1 July 1960. The 4158th SW provided host station support functions for SAC wing and support elements deployed to Elmendorf during deployments from United States bases, primarily weather reconnaissance flights used for long range detection of Soviet Soviet atomic explosions with RC-135 operations. The 4158th SW inactivated in 1966 when SAC moved out of Elmendorf. The 4157th Strategic Wing was replaced at Eielson by the 6th Strategic Wing in March 1967. The 6th SW remained stationed at Eielson until being inactivated on 1 September 1992 as part of the reorganization of the USAF command structure after the collapse of the Soviet Union. Cold War The outbreak of the Cold War in 1948 caused a major buildup of air defense forces in Alaska, as the airspace over the Arctic and Alaska was believed by Air Force planners to be the "Front Line" in case of an armed conflict between the United States and the Soviet Union for the North American continent. Alaskan Air Command was initially divided into two air defense sectors – Aleutian and Yukon. The defense of the Yukon sector was initially directed from Ladd AFB, near Fairbanks, Alaska. In 1950, the 11th Air Division (11th AD) was activated at Ladd, replacing the Yukon Sector; the 10th Air Division (10th AD) at Elmendorf AFB, replacing the Aleutian Sector. The 10th AD was responsible for the Aircraft Control and Warning (Radar) stations in southern Alaska and for the 64th, 65th and 66th Fighter-Interceptor Squadrons which were assigned directly to the division after