Noun
a command of the United States Air Force that is responsible for defending the United States through its space and intercontinental ballistic missile operations
Source: WordNetUSAF nuclear forces in ACC and AFSPC were then combined with the United States Navy 's Fleet Ballistic Missile submarine forces to form the United States Strategic Command ( USSTRATCOM ), which took over the SAC Headquarters complex at Offutt AFB. Source: Internet