sentences:  In the early 1960s, the B-47 was considered to be reaching obsolescence, and was being phased out of SAC's strategic arsenal.At Forbes, the 40th Bomb Wing gained an Atlas missile squadron in January 1964, and was redesignated the 40th Strategic Aerospace Wing on 1 February 1964.Began phasing down for inactivation with the retirement of its B-47s during the spring of 1964 and was designated as non-operational from 15 August, to 1 September 1964.