SM-65 Atlas

The SM-65 Atlas was the first intercontinental ballistic missile (ICBM) developed and deployed by the United States. It was built for the U.S. Air Force by Convair Division of General Dynamics at the Kearny Mesa assembly plant north of San Diego, California. Atlas became operational as an ICBM in October 1959 and was used as a first stage for satellite launch vehicles for half a century. The Atlas missile's warhead was over 100 times more powerful than the bomb dropped over Nagasaki in 1945.

An initial development contract was given to Consolidated Vultee Aircraft (Convair) on 16 January 1951 for what was then called MX-1593, but at a relatively low priority. The 1953 testing of the first dry H-bomb in the Soviet Union led to the project being dramatically accelerated. The initial design completed by Convair in 1953 was larger than the missile that eventually entered service. Estimated warhead weight was lowered from 8000 pounds to 3000 pounds based on highly favorable U.S. nuclear warhead tests in early 1954, and on 14 May 1954 the Atlas program was formally given the highest national priority. 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. 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 28 November 1958. Atlas ICBMs were deployed operationally from 31 October 1959 to 12 April 1965.

On 18 December 1958, the launch of Atlas 10B sent the missile into orbit around the Earth (without use of an upper stage) carrying the "SCORE" (Signal Communications by Orbiting Relay Equipment) communications payload. Atlas 10B/SCORE, at 8750 lb, was the heaviest man-made object then in orbit, the first voice relay satellite, and the first man-made object in space easily visible to the naked eye due to the large, mirror-polished stainless steel tank. This was the first flight in what would be a long career for the Atlas as a satellite launcher. Many retired Atlas ICBMs would be used as launch vehicles, most with an added spin-stabilized solid rocket motor upper stage for polar orbit military payloads. Even before its military use ended in 1965, Atlas had placed four Mercury astronauts in orbit and was becoming the foundation for a family of successful space launch vehicles, most notably Atlas Agena and Atlas Centaur.

Mergers led to the acquisition of the Atlas Centaur line by Lockheed-Martin which in turn became part of the United Launch Alliance. Today Lockheed-Martin and ULA support a new Atlas rocket family based on the larger "Atlas V" which still uses the unique and highly efficient Centaur upper stage. Atlas V stage one is powered by a Russian RD-180 oxygen/kerosene engine and uses conventional aluminum isogrid tankage rather than the thin-wall, pressure-stabilized stainless steel tanks of the original Convair Atlas. Payload weights have increased along with launch vehicle weights over the years so the current Atlas V family serves many of the same type commercial, DoD, and planetary missions as earlier Atlas Centaurs.