at high subsonic speeds and primarily designed for penetrating the airspace of the Soviet Union in 1953. The wing trained the initial B-47 cadre for the 96th Bombardment Wing, from December 1953 to January 1955 and subsequently deployed as a wing to RAF Brize Norton, England from 5 June to 4 September 1954 and Andersen Air Force Base, Guam from 5 October 1956 to 11 January 1957. In the late 1950s, the B-47 Stratojet was considered to be reaching obsolescence, and was being phased out of SAC's strategic arsenal. Aircraft were reassigned to other SAC units as replacements in late 1959 and 1960 becoming non-operational. B-52 Era 4134th Strategic Wing With the retirement of the Stratojet, the 320th Bomb Wing was reassigned to Mather Air Force Base, California, an Air Training Command (ATC) base, on 1 February 1963 where it assumed the assets of the 4134th Strategic Wing, a SAC tenant organization at Mather. The 4134th was established by SAC on 1 May 1958 at Mather and assigned to the 14th Air Division as part of SAC's plan to disperse its Boeing B-52 Stratofortress heavy bombers over a larger number of bases, thus making it more difficult for the Soviet Union to knock out the entire fleet with a surprise first strike. The wing was assigned only two maintenance squadrons until 1 July 1958 when the 72d Bombardment Squadron, consisting of 15 B-52Fs. moved to Mather from Travis Air Force Base, California where it had been one of the three squadrons of the 5th Bombardment Wing. Starting in 1960, one third of the squadron's aircraft were maintained on fifteen-minute alert, fully fueled and ready for combat to reduce vulnerability to a Soviet missile strike. This was increased to half the squadron's aircraft in 1962. The 4039th (and later the 416th) continued to maintain an alert commitment until 1965, and periodically thereafter when not supporting operations in Southeast Asia. Additional maintenance squadrons and a squadron to provide security for special weapons were activated at the same time. On 1 January 1959 the 49th Aviation Depot Squadron was activated to oversee the wing's special weapons. The 4135th became fully organized on 1 July 1959 when the 904th Air Refueling Squadron, flying Boeing KC-135 Stratotankers was activated and assigned to the wing. In 1962, the wing's bombers began to be equipped with the GAM-77 Hound Dog and the GAM-72 Quail air-launched cruise missiles,