The SM-65 Atlas was the first operational ICBM developed by the United States. It was built for the USAF by the Convair Division of General Dynamics. Atlas was the most complicated missile ever built for the U.S. military, and because of this its development has been characterized as chaotic, the result being many failures during test launches. The initial missile project, MX-774, was named for the Greek god Atlas, which perhaps not coincidentally, was the contractor’s parent organization, Atlas Corporation. This probably started the tradition of naming subsequent large missiles after other mythological gods. The Atlas program began in 1946 but did not really get off the ground until the 1950s, following suspicions that the Soviets were engaging in ICBM research. This led to the project being dramatically accelerated, and Atlas became a crash program of the highest national importance on 14 May 1954. A major development and test contract was awarded to Convair on 14 January 1955 for a 10-foot diameter missile to weigh about 250,000 pounds, fully loaded. Atlas was informally classified as a “stage-and-a-half” booster, with a central sustainer engine and two booster engines that were all started at launch, each drawing from a single set of propellant tanks. About two minutes into flight, the boosters and their supporting skirt were jettisoned. Atlas development was tightly controlled by the Air Force’s Western Development Division (WDD), later part of the Air Force Ballistic Missile Division. Contracts for warhead, guidance, and propulsion were handled separately by WDD. The first successful flight of a highly instrumented Atlas missile to full range occurred on 28 November 1958, and the Atlas ICBMs were deployed operationally beginning on 31 October 1959. The missile was originally designated as the XB-65 experimental bomber; in 1955 it was redesignated SM-65 (“Strategic Missile 65”) and, from 1962, it became CGM-16. The letter “C” stood for “coffin” or “container” because the missile was stored in a semi-hardened coffin-like facility. It was prepared for launch by being raised and fueled in the open. As time progressed, a number of models were produced. The Atlas missiles A through D (A-C were prototypes, D was the first operational Atlas) used radio guidance: the missile sent information from its inertial system to a ground station by radio, and received course correction information in return. The Atlas E and F models had completely autonomous inertial guidance systems. The Atlas-F (SM-65F) was the final operational variant of the Atlas missile. It first flew on 8 August 1961 and was deployed as an operational ICBM from late 1962 to early 1965. The Atlas-F was essentially a quick-firing version of the Atlas-E, modified to be stored in a vertical position inside underground concrete and steel silos. It was nearly identical to the E version except for interfaces associated with their different basing modes and the fuel management system. When stored, the missile sat atop an elevator. If placed on alert, it was fueled with RP-1 (high-grade kerosene) fuel, which could be stored inside the missile for extended periods. If a decision were made to launch, it was loaded with liquid oxygen (LOX). Once the LOX was aboard, the elevator raised the missile to the surface for launching. This method of storage allowed the Atlas F to be launched in about ten minutes, a saving of about five minutes over the Atlas D and Atlas E, both of which were stored horizontally and had to be raised to a vertical position before being fueled. The RVs and warheads were improved too, as can be seen when comparing images of early Atlas missiles on alert to those in service by 1964. About 350 Atlas ICBMs of all versions were built, with a peak deployment level of 129 (30 D, 27 E, and 72 F). By 1965, the second-generation Titan missile (Titan II) and the solid-fueled Minuteman were on alert, rendering the Atlas obsolete, so the last Atlas ICBMs were removed from service that year. Despite its relatively short life as an ICBM, Atlas served as the proving ground for many new missile technologies. Perhaps more importantly, its development spawned the organization, policies, and procedures that paved the way for all of the later ICBM programs. After retirement from operational ICBM service, the Atlas boosters were refurbished and used for close to 40 years as space launch vehicle vehicles. A lasting legacy of the Atlas weapon system is the lubricant called WD-40, developed for the Atlas as a corrosion inhibitor for the missile’s outer skin, still available for purchase in stores today!