The Convair B-58 Hustler was the first operational supersonic jet bomber, and the first capable of Mach 2 flight. The aircraft was developed for the United States Air Force for service in the Strategic Air Command (SAC) during the 1960s. Originally intended to fly at high altitudes and speeds to avoid Soviet fighters, the introduction of highly accurate Soviet surface-to-air missiles forced the B-58 into a low-level penetration role that severely limited its range and strategic value. This led to a brief operational career between 1960 and 1969. Its specialized role was succeeded by other American supersonic bombers, such as the FB-111A and the later B-1B Lancer.