The 577th Strategic Missile Squadron (577 SMS) is an inactive United States Air Force unit. It was last assigned to the 11th Strategic Aerospace Wing, stationed at Altus AFB, Oklaholma. On 1 July 1961, the 577th Strategic Missile Squadron (ICBM-Atlas) went on alert as a Strategic Air Command (SAC) Intercontinental ballistic missile (ICBM) squadron, being equipped with the SM-65F Atlas, with a mission of nuclear deterrence. The squadron was inactivated as part of the phaseout of the Atlas ICBM on 25 March 1965.