The 550th Strategic Missile Squadron (550 SMS) is an inactive United States Air Force unit. It was last assigned to the 310th Strategic Aerospace Wing, stationed at Shilling AFB, Kansas The 550 SMS was equipped with the SM-65F Atlas Intercontinental ballistic missile (ICBM), with a mission of nuclear deterrence. The squadron was inactivated as part of the phaseout of the Atlas ICBM on 25 June 1965.