In October of 1959, America's first land-based nuclear-tipped intercontinental ballistic missile went on around-the-clock alert. It was an Air Force Atlas D model missile at Vandenberg Air Force Base, Calif. Gen. Thomas S. Power, then commander-in-chief of Strategic Air Command, declared it operational following a successful Sept. 9, 1959, test launch, which saw the missile accelerate to a speed of 16,000 mph and traveling 4,300 miles. He stated that attaining alert status was a "tremendous milestone" for the United States Air Force, the ICBM and national defense.
Ogden Air Logistics History Office