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The Atlas ballistic missile began with the US Army Air Corps request for proposal in October 1945, which led to development in the 1950’s of the Atlas, Navaho, Snark, and Matador/Mace missiles. By January 10, 1946, Consolidated-Vultee’s engineers, under the leadership of Belgian-born Karel Bossart, submitted their proposals for two 6,000-nautical mile missiles: one subsonic, winged, and jet powered; the other supersonic, ballistic, and rocket powered. New technologies proposed for the ballistic missile included extremely low structural weight through use of steel monocoque single-wall construction tanks, kept rigid by internal tank pressure; gimballed rocket engines; detachable payload or warhead section; and nearly single-stage to orbit performance through the ‘stage-and-a-half’ approach of jettisoning the booster engines during the ascent.

On April 19, Convair received a contract for $1,893,000 to include fabrication and testing of 10 MX-774 Hiroc missiles to verify Bossart’s innovative concepts. Captive testing of the MX-774 research rockets began in San Diego in 1947. In June , Consolidated Vultee was notified that it had lost the cruise missile competition; Northrop and Martin received contracts for development of the subsonic jet-powered designs. History would show that these lead to dead ends whereas the Atlas would be flying at least sixty years later. Defense cutbacks forced the Air Force to terminate the contract in July 1947, only three months before the first scheduled flight. The remaining contract funds did allow three MX-774's to be test-launched at White Sands Proving Ground in July-December 1947. Further work at Convair was reduced to ‘Mafia’ low-level design activity using company funds.

The outbreak of the Korean war and the beginning of the cold war loosened the federal purse strings. Convair received a new contract (MX-1593) in September 1951 to begin design of a ballistic missile incorporating the design features validated by the MX-774. In 1953 the now-Convair Division of General Dynamics presented a plan to the Air Force for an accelerated program.

A major propulsion problem in the early 1950's was that liquid rocket motor ignition reliability was less than 50 percent. This led to the stage-and-a-half concept, with all engines ignited prior to lift-off and the booster engines jettisoned during flight. This allowed confirmation that all engines were functioning correctly before releasing the missile for flight.

A full go-ahead for the Atlas design was ordered in January 1955 as Weapon System WS107A-l. At Convair the project was known the Model 7 (in Russia, Korolev was working on the competing R-7 ICBM - evidently both sides wanted to use the lucky number). In September 1955, faced with intelligence reports of Russian progress on their ICBM, the Atlas received the highest national development priority. The project became one of the largest and most complex production, testing, and construction programs ever undertaken. The first propulsion system and component tests were conducted in June 1956; the first captive and flight-test missiles were completed later the same year.

The first Atlas A flight took place on June 11, 1957. The first operational missile, the Atlas D, was the basis for launching the Mercury manned spacecraft into orbit. By use of Agena and Centaur upper stages, the Atlas became the medium-lift workhorse of American manned, planetary, and geosynchronous-orbit space programs. Stretched several times, the latest version, the Atlas IIAR, will finally dispense with the booster engine stage in place of two Russian-design rocket engines. Although never copied by other designers, the inflated steel tank approach of the Atlas still gives it the lowest empty weight ratio ever achieved without any reliability penalty.


After the retirement of the Atlas-Agena in 1978, the Centaur stage became standard on Atlas Launch Vehicles. Lox/LH2 was universally recognized by the space pioneers as the ultimate liquid propellant combination, but use was delayed due to problem of handling the cryogenic liquid hydrogen fuel. NASA's Lewis Research Center (LeRC) did much pioneering work in development of liquid hydrogen technology. LeRC fired the first experimental Lox/LH2 engine of 5,000 pounds thrust in 1953. Centaur itself began with a contract awarded to General Dynamics by the Advanced Research Project Agency in 1958. The first space vehicle to use liquid hydrogen, Centaur was a pioneering project that solved the many technical problems of using the super-cryogenic, explosive, and highly volatile fuel. Pratt & Whitney Aircraft was awarded the contract to develop Centaur's RL-10 engines. The US Air Force built the first large-quantity liquid hydrogen production facility

In 1962, with the hydrogen propulsion technology being vital to the success of the Apollo program, LeRC was assigned technical management of Centaur. The Centaur project was given the highest DX priority. The first successful flight of Centaur atop Atlas occurred in November 1963. This included the first in-flight ignition of a hydrogen-powered vehicle. However thereafter the Von Braun team’s Saturn S-IV stage, using six of the RL-10 motors, leapfrogged the Surveyor . By the time of the first operational Centaur mission, Surveyor l, in May 1966, the S-IV had already completed its test series of six orbital flights. Yet thirty years later, the Saturn is long gone, and the Centaur continues, having been launched or planned for launch from Atlas, Titan, Delta, and Shuttle vehicles. Production is expected to continue well into the 21st century, and no replacement for the RL-10 engine, the ultimate engine using the ultimate propellants, has been possibl


Launch Vehicle: MX-774. Project MX-774 inaugurated by AAF with Consolidated-Vultee to study rocket capabilities with an ICBM as a final objective. Limited funds permitted a few test launches. These rockets demonstrated technologies that woud later be applied to the Atlas.

Launch Vehicle: Atlas A. First test model of Atlas ICBM. Two booster engines, no sustainer, dummy warhead. 50% reliability in 8 flight tests.

Launch Vehicle: Atlas B. First all-up version of Atlas ICBM, with jettisonable booster engines and single engine sustainer on core. '1 1/2' stage launch vehicle.

Launch Vehicle: Atlas C. Last development version of Atlas. Never deployed operationally or used for space launches.

Launch Vehicle: Atlas D. First operational version of Atlas ICBM and used as launch vehicle for Project Mercury.

Launch Vehicle: Atlas Vega.

Atlas-Vega consisted of an Atlas booster with a storable propellant upper stage. It was planned by NASA at its inception for deep space and planetary missions before the Atlas Centaur was available. Work had already begun when NASA discovered that the CIA and the US Air Force had an essentially identical launch vehicle (Atlas-Hustler, later called Atlas-Agena) in development for the highly classified Corona reconnaisance satellite program. Atlas-Vega was accordingly cancelled.


Launch Vehicle: Atlas E. Initial fully operational version of Atlas ICBM. Differed in guidance system from Atlas F. Deployed as missiles from 1960 to 1966. After retirement, the ICBM's were refurbished and used over twenty years as space launch vehicles.

Launch Vehicle: Atlas F. Final operational version of Atlas ICBM. Differed in guidance systems. Deployed as missiles from 1961 to 1966. After retirement, the ICBM's were refurbished and used over twenty years as space launch vehicles.

Launch Vehicle: Atlas Able. Atlas with upper stage based on Vanguard second stage.

Launch Vehicle: Atlas LV-3A / Agena A. Agena originally called 'Hustler', based on engine for cancelled rocket-propelled nuclear warhead pod for B-58 Hustler bomber.

Launch Vehicle: Atlas LV-3A / Agena B. Improved, enlarged Agena upper stage.

Launch Vehicle: Atlas LV-3B / Mercury. Atlas D modified for use in Project Mercury.

Launch Vehicle: SLV-3 Atlas. Standardized Atlas booster with no or small solid upper stage.

Launch Vehicle: SLV-3 Atlas / Agena B. Standardized Atlas booster with Agena B upper stage.

Launch Vehicle: Atlas Centaur LV-3C. First test version of Atlas with Centaur upper stage.

Launch Vehicle: Atlas / Agena D SLV-3A. Uprated Atlas booster with Atlas D upper stage.

Launch Vehicle: Atlas LV-3A / Agena D. Further improved and lightened Agena upper stage.

Launch Vehicle: SLV-3 Atlas / Agena D. Standardized Atlas booster with Agena D upper stage.

Launch Vehicle: Atlas Centaur SLV-3C. First test version of Atlas with Centaur upper stage.

Launch Vehicle: Atlas Centaur SLV-3D. Fully developed version of Atlas with Centaur upper stage.

Launch Vehicle: Atlas G. Atlas-Centaur launch vehicles using stretched, uprated Atlas core.

Launch Vehicle: Atlas H. Atlas H used the Atlas first stage developed for the Atlas G vehicle. It was flown without the Centaur upper stage.

Launch Vehicle: Atlas I.

The Atlas I launch vehicle was derived from the Atlas G, and included the same basic vehicle components (Atlas booster and Centaur upper stage). Significant improvements in the guidance and control system were made with an emphasis on replacing analog flight control components with digital units interconnected with a digital data bus. The first flight of an Atlas I was on July 25, 1990. Originally, 18 Atlas I vehicles were planned for manufacture. With the award by the USAF to General Dynamics of the MLV-II vehicle development contract for the Atlas II launch vehicle, the Atlas program rescoped Atlas I production commitments to 11 vehicles and converted the remaining commitments to the Atlas II/IIA/IIAS production effort.


Launch Vehicle: Atlas II.

The Atlas II booster was 2.7-meters longer than an Atlas I and included uprated Rocketdyne MA-5A engines. The Atlas I vernier engines were replaced with a hydrazine roll control system. The Centaur stage was stretched 0.9-meters compared to the Centaur I stage. Fixed foam insulation replaced Atlas I's jettisonable insulation panels. The original Atlas II model was developed to support the United States Air Force Medium Launch Vehicle II program. Its Centaur used RL10A-3-3A engines operating at an increased mixture ratio. The first Atlas II flew on 7 December 1991, successfully delivering AC-102/Eutelsat II F3 to orbit.


Launch Vehicle: Atlas IIA.

The Atlas II booster was 2.7-meters longer than an Atlas I and included uprated Rocketdyne MA-5A engines. The Atlas I vernier engines were replaced with a hydrazine roll control system. The Centaur stage was stretched 0.9-meters compared to the Centaur I stage. Fixed foam insulation replaced Atlas I's jettisonable insulation panels. Atlas IIA was a commercial derivative of the Atlas II developed for the US Air Force. Higher performance RL10A-4 (or RL10A-4-1) engines replaced Atlas II's RL10A-3-3A engines. RL10A-4 and RL10A-4-1 engines were offered with or without extendable nozzles (Extendible nozzles increased the engines specific impulse, providing additional performance if required). AC-105 / INTELSAT-K, launched 9 June 1992, inaugurated Atlas IIA series flights.


Launch Vehicle: Atlas IIAS.

The Atlas II booster was 2.7-meters longer than an Atlas I and included uprated Rocketdyne MA-5A engines. The Atlas I vernier engines were replaced with a hydrazine roll control system. The Centaur stage was stretched 0.9-meters compared to the Centaur I stage. Fixed foam insulation replaced Atlas I's jettisonable insulation panels. Higher performance RL10A-4 (or RL10A-4-1) engines replaced Atlas II's RL10A-3-3A engines. RL10A-4 and RL10A-4-1 engines were offered with or without extendable nozzles (Extendible nozzles increased the engines specific impulse, providing additional performance if required). The Atlas IIAS model added four Thiokol Castor IVA solid rocket boosters (SRBs) to the core Atlas stage to augment thrust for the first two minutes of flight. The first SRB pair was ignited at liftoff and burned for 54 seconds. The second pair was ignited in flight when vehicle loading constraints were satisfied. Both pairs were jettisoned shortly after their respective burnouts. The first Atlas IIAS successfully launched AC-108 / Telstar 401 on 15 December 1993.


Launch Vehicle: Atlas IIIA.

Development of Atlas using Russian engines in place of booster/sustainer group used on all previous models. First stage couples unique Atlas balloon tanks and high performance Glushko engines. The Atlas IIIA is the centerpiece of Lockheed Martin's strategy to remain the leader in the commerical launch services industry. Launch Sequence: In a typical Atlas IIIA launch, the vehicle's two RD-180 thrust chambers are ignited shortly before liftoff. Pre-programmed engine thrust settings are used during booster ascent to minimize vehicle loads by throttling back during peak transonic loads/high dynamic pressure region while otherwise maximizing vehicle performance. Just over two minutes into flight, as the vehicle reaches an axial acceleration of 4 g's, the engines begin to throttle back, eventually initiating a constant throttle rate to sustain acceleration at 5.5 g's. Booster engine cutoff occurs approximately three minutes into flight and is followed by separation of Centaur from Atlas. The first Centaur burn lasts about nine minutes after which the Centaur and its payload coast in a parking orbit. During the first burn, approximately ten seconds after ignition, the payload fairing is jettisoned. The second Centaur ignition occurs about 23 minutes into the flight, continues for about three minutes, and is followed several minutes later by the separation of the spacecraft from Centaur. Major Suppliers: NPO Energomash / Pratt & Whitney - Atlas RD-180 engines; Pratt & Whitney - Centaur engines; Honeywell - Inertial Navigation Unit; BF Goodrich - Digital acquisition system; SAAB - Payload Separation Systems.


Launch Vehicle: Atlas IIIB.

Atlas IIIB added performance capability complements its sister configuration Atlas IIIA. First flight of the Atlas IIIB is planned for mid-2000, subject to satellite availability. The single-stage Atlas IIIB booster is the same as Atlas IIIA The Lockheed Martin manufactured Centaur upper stage is powered by two Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. The changes to Centaur for Atlas IIIB are a stretched tank (1.68 m) and the addition of the second engine. Guidance, tank pressurization, and propellant usage controls for both Atlas and Centaur phases are provided by the inertial navigation unit (INU) located on the forward equipment module. Launch Sequence: In a typical Atlas IIIB launch, the vehicle's two RD-180 thrust chambers are ignited shortly before liftoff. Pre-programmed engine thrust settings are used during booster ascent to minimize vehicle loads by throttling back during peak transonic loads/high dynamic pressure region while otherwise maximizing vehicle performance. Just over two minutes into flight, as the vehicle reaches an axial acceleration of 4 g's, the engines begin to throttle back, eventually initiating a constant throttle rate to sustain acceleration at 5.5 g's. Booster engine cutoff occurs approximately three minutes into flight and is followed by separation of Centaur from Atlas. The first Centaur burn lasts about five minutes, after which the Centaur and its payload coast in a parking orbit. During the first burn, approximately eight seconds after ignition, the payload fairing is jettisoned. The second Centaur ignition occurs 27 minutes into the flight, continues for about three minutes, and is followed several minutes later by the separation of the spacecraft from Centaur. Major Suppliers: NPO Energomash / Pratt & Whitney - Atlas RD-180 engines; Pratt & Whitney - Centaur engines; Honeywell - Inertial Navigation Unit; BF Goodrich - Digital acquisition system; SAAB - Payload Separation Systems .


Launch Vehicle: Atlas V.

The Atlas V launch vehicle system is based on the 3.8-m (12.5-ft) diameter Common Core Booster (CCB) powered by a single RD-180 engine. When combined with a standard Atlas payload fairing, the configuration is part of the Atlas V 400 series. The Atlas V 500 series combines the CCB with a larger and 5 m diameter payload fairing derived from that used on the Ariane 5 vehicle The Atlas V 500 series can also tailor performance by incorporating from zero to five solid rocket boosters (SRB).

Both Atlas V 400 and 500 configurations incorporate a stretched version of the Centaur upper stage (CIII), which can be configured as a single-engine Centaur (SEC) or a dual engine Centaur (DEC). The Atlas V family of launch vehicles can be launched from either Cape Canaveral Air Station Launch Complex 41 or Vandenberg Air Force Base Space Launch Complex 3W.


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Last update 3 May 2001.
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