List of USAF Strategic Missile Wings assigned to Strategic Air Command The eruption of the Cold War as a result of the Berlin Blockade produced sweeping changes in the United States ' military establishment and society at large . For more than 40 years the nation prepared to fight a war that never came . The development of Intercontinental ballistic missile ( ICBM ) technology as an outgrowth of the World War II V - 2 rocket technology developed by Germany , and the mating of Nuclear weapon technology developed by the United States created an entire new method of warfare . Due to their great range and firepower , in an all - out nuclear war , land - based ICBMs would carry most of the destructive force , with long - range , nuclear - armed bombers and Submarine - launched ballistic missile s having the remainder . These three components were collectivity referred to as the United States Nuclear triad . The United States Air Force Strategic Air Command ( SAC ) was the United States military command and control organization for two of the components of the triad during the Cold War , ICBMs and nuclear - armed bombers . Over a million men and women served in SAC , its forces on alert 24 hours a day , every day , with a mission to preserve the peace and deter any aggressor nation from attacking the United States and its allies . This is a list of the three generations of ICBMs produced and operationally deployed by the United States during the Cold War , with a fourth generation ICBM being deployed in small numbers at the generally agreed end of the Cold War in 1991 . Note : The PGM - 17 Thor and PGM - 19 Jupiter Medium - range ballistic missile s ( MRBM ) , or the SM - 62 Snark intercontinental cruise missile developed by the United States Air Force in the 1950s are not included on this list . SM - 65 Atlas . The First Generation SM - 65 Atlas , first flown in 1957 , was the United States ' first successful ICBM . It was taken out of active service in 1965 . Strategic Air Command deployed Atlas models D , E , and F . As an emergency measure , in September 1959 the Air Force deployed three SM - 65D Atlas missiles on open launch pads at Vandenberg AFB , California , under the operational control of the 576th Strategic Missile Squadron , 704th Strategic Missile Wing . Completely exposed to the elements , the three missiles were serviced by a gantry crane . One missile was on operational alert at all times . They remained on alert until 1 May 1964 Operational SM - 65D Atlas missiles were deployed to the following units : Operational SM - 65E Atlas missiles were deployed to the following units : Operational SM - 65F Atlas missiles were deployed to the following units : A modified version of the Atlas - D ( Atlas LV - 3B ) was used in the NASA Project Mercury program and successfully launched four astronauts into space ( 1962 – 1963 ) . A variant was also used in the Project Gemini program ( 1966 ) HGM - 25A Titan I . The First Generation HGM - 25A Titan I , first flown in 1959 , the United States ' first true multistage ICBM . It was taken out of active service in 1965 . LGM - 25C Titan II . The Second Generation LGM - 25C Titan II , first flown in 1961 , was the successor to the Titan I , and carried a payload twice as heavy . It also used sortable propellants , which reduced the time to launch and permitted it to be launched from its silo . Titan II carried the largest single warhead of any American ICBM to date . It was taken out of active service in 1987 . A modified version of the Titan II ( Titan II GLV ) was used during the NASA Project Gemini program with ten manned launches of spacecraft . ( 1965 – 1966 ) . LGM - 30 Minuteman . The Third Generation LGM - 30 Minuteman , first flown in 1961 was developed to replace the hazards inherent in the caustic , volatile liquid - fuel systems of the Atlas and Titan ICBMS . It took 15 minutes to pump 249 , 000 pounds of propellant aboard the " quick firing " Atlas F . It was dangerous work . Four Atlas silos were destroyed when propellant - loading exercises went awry . Two Titan I silos also met a similar fate . The Minuteman had two innovations that gave it a long practical service life : a solid rocket booster , and a digital flight computer . This computer was one of the very first recognizably modern embedded systems . The solid rocket booster made the Minuteman faster to launch than other ICBMs , which used liquid fuels . Support . Today , all United States ICBMs are LGM - 30G Minuteman IIIs . The Air Force planned to keep the missile in service until 2020 , but it may be upgraded to stay in service until 2030 . LGM - 118 Peacekeeper . The fourth - generation LGM - 118 Peacekeeper initially known as the " MX missile " ( for Missile - eXperimental ) , was a land - based ICBM deployed by the United States starting in 1986 . A total of 50 missiles were deployed . They were withdrawn from operational service in the early 2000s ( decade ) , the last taken offline in 2005 , primarily for budetary reasons . Armed with up to 10 re - entry vehicles each carrying a W - 87 thermonuclear warhead , the Peacekeeper was the most powerful ICBM deployed by the United States .