Atlas V EELV - Lockheed-Martin
The Lockheed Martin Atlas V resulted from Lockheed Martin's combination of the best practices from both the Atlas and Titan programs into an evolved commercial and government launch system for the 21st century. Atlas V built on the design innovations demonstrated on Atlas III and incorporated a structurally stable booster propellant tank, enhanced payload fairing options and optional strap-on solid rocket boosters.
The first four Atlas V were successfully launched on 21 August 2002, 13 May 2003, 17 July 2003, and 17 December 2004 respectively. These launches represented two flights each of two different Atlas V configurations. The Atlas V family uses a single-stage Atlas main engine, the Russian RD-180 and the newly developed Common Core Booster (CCB) with up to five strap-on solid rocket boosters. The CCB is 12.5 ft. (3.8 m) in diameter by 106.6 ft. (32.5m) long and uses 627,105 lbs. (284,453 kg) of liquid oxygen and RP-1 rocket fuel propellants.
The Atlas V-Heavy (Atlas V-H) configuration has been available available 30 months from order. It would use three CCB stages strapped together to provide the capability necessary to lift the heaviest spacecraft.
Additionally, on Atlas V, Lockheed Martin introduced a 4.57-meter usable diameter Contraves payload fairing in addition to retaining the option to use the heritage Atlas payload fairings. The Contraves fairing was a composite design and is based on flight proven hardware. Three configurations would be manufactured to support Atlas V. The short and medium length configurations would be used on the Atlas V 500 series. The long configuration would be used on the Atlas V-H.
The Centaur upper stage uses a pressure stabilized propellant tank design and cryogenic propellants. The Centaur stage for Atlas V was stretched 5.5 ft (1.68 m) and is powered by either one or two Pratt & Whitney RL10A-4-2 engines, each engine developing a thrust of 22,300 lbs. (99.2 kN). Operational and reliability upgrades were enabled with the RL10A-4-2 engine configuration. The inertial navigation unit (INU) located on the Centaur provides guidance and navigation for both Atlas and Centaur, and controls both Atlas and Centaur tank pressures and propellant use. The Centaur engines are capable of multiple in-space starts, making possible insertion into low-earth parking orbit, followed by a coast period and then insertion into GTO. An upgrade to a Fault Tolerant INU is currently in development and will further enhance mission reliability for all Atlas vehicles.
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