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|family = |derivatives = Vulcan |comparable = |status = Active |sites = Cape Canaveral SLC-41 Vandenberg SLC-3E |launches = 59 (401: 29, 411: 3, 421: 5, 431: 2) (501: 6, 521: 2, 531: 3, 541: 3, 551: 6) |success = 58 (401: 28, 411: 3, 421: 5, 431: 2) (501: 6, 521: 2, 531: 3, 541: 3, 551: 6) |fail = |partial = 1 (401)〔(Gunter's Space Page – Atlas V (401) ). Space.skyrocket.de. Retrieved on 2011-11-19. 〕 |other_outcome = |first = 401: 21 August 2002 411: 20 April 2006 421: 10 October 2007 431: 11 March 2005 501: 22 April 2010 521: 17 July 2003 531: 14 August 2010 541: 26 November 2011 551: 19 January 2006 |last = |only = |payloads = Mars Reconnaissance Orbiter New Horizons LRO/LCROSS Solar Dynamics Observatory Boeing X-37B Juno Mars Science Laboratory |stagedata = }} Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance. Each Atlas V rocket uses a Russian-built RD-180 engine burning kerosene and liquid oxygen to power its first stage and an American-built RL10 engine burning liquid hydrogen and liquid oxygen to power its Centaur upper stage. The RD-180 engines are provided by RD AMROSS, while Aerojet Rocketdyne provides both the RL10 engines and the strap-on boosters used in some configurations. The standard payload fairing sizes are 4 or 5 meters in diameter and of various lengths, and are made by RUAG Space. Fairings sizes as large as 7.2 m in diameter and up to 32.3 m in length have been considered. The rocket is assembled in Decatur, Alabama; Harlingen, Texas; San Diego, California; and at United Launch Alliance's headquarters near Denver, Colorado.〔(Launch Vehicles ). Lockheed Martin (2002-08-21). Retrieved on 2011-11-19. 〕 In its more than four dozen launches, starting with its maiden launch in August 2002, Atlas V has had a near-perfect success rate. One flight on June 15, 2007, NRO L-30, experienced an upper-stage anomaly when the engine in the vehicle's Centaur upper stage shut down four seconds early, leaving the payload—a pair of naval signals intelligence satellites—in a lower than intended orbit. However, the customer, the National Reconnaissance Office, categorized the mission as a success. ==History== The Atlas V is the newest member of the Atlas family. Compared to the Atlas III vehicle, there are numerous changes. Compared to the Atlas II, it is a near-redesign. There was no Atlas IV. # The ''"1.5 staging"'' technique was dropped on the Atlas III, in favor of a more-advanced RD-180 engine. The RD-180 features a dual-combustion chamber, dual-nozzle design and is fueled by a kerosene/liquid oxygen mixture. # The main-stage diameter increased from 10 feet to 12.5 feet. As with the Atlas III, the different mixture ratio of the engine called for a larger oxygen tank (relative to the fuel tank) compared to Western engines and stages. # The first stage tanks no longer use stainless steel monocoque "balloon" construction. The tanks are isogrid aluminum and are stable when unpressurized.〔 # Use of aluminum, with a higher thermal conductivity than stainless steel, requires insulation for the liquid oxygen. The tanks are covered in a polyurethane-based layer. # Accommodation points for parallel stages, both smaller solids and identical liquids, are built into first stage structures.〔 The Atlas V was developed by Lockheed Martin Commercial Launch Services as part of the US Air Force Evolved Expendable Launch Vehicle (EELV) program and made its inaugural flight on August 21, 2002. The vehicle operates out of Space Launch Complex 41 at Cape Canaveral Air Force Station and Space Launch Complex 3-E at Vandenberg Air Force Base. Lockheed Martin Commercial Launch Services continues to market the Atlas V to commercial customers worldwide. The Atlas V first stage, the Common Core Booster (CCB), is 12.5 ft (3.8 m) in diameter and 106.6 ft (32.5 m) in length. It is powered by a single Russian RD-180 main engine burning 627,105 lb (284,450 kg) of liquid oxygen and RP-1. The booster operates for about four minutes, providing about 4 meganewtons (860,000 lbf) of thrust.〔 Thrust can be augmented with up to five Aerojet strap-on solid rocket boosters, each providing an additional 1.27 meganewtons (285,500 lbf) of thrust for 94 seconds. The Centaur upper stage uses a pressure stabilized propellant tank design and cryogenic propellants. The Centaur stage for Atlas V is stretched 5.5 ft (1.68 m) relative to the Atlas IIAS Centaur and is powered by either one or two Aerojet Rocketdyne RL10A-4-2 engines, each engine developing a thrust of 99.2 kN (22,300 lbf). The inertial navigation unit (INU) located on the Centaur provides guidance and navigation for both the 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. A subsequent third burn following a multi-hour coast can permit direct injection of payloads into geostationary orbit. , the Centaur vehicle had the highest proportion of burnable propellant relative to total mass of any modern hydrogen upper stage and hence can deliver substantial payloads to a high energy state. Many systems on the Atlas V have been the subject of upgrade and enhancement both prior to the first Atlas V flight and since that time. Work on a new Fault Tolerant Inertial Navigation Unit (FTINU) started in 2001 to enhance mission reliability for Atlas vehicles by replacing the existing non-redundant navigation and computing equipment with a fault tolerant unit.〔(Honeywell awarded $52 million Atlas V contract – Military & Aerospace Electronics ). Militaryaerospace.com (2001-05-01). Retrieved on 2011-11-19. 〕 The upgraded FTINU first flew in 2006,〔(Atlas V Launch Services User's Guide ). United Launch Alliance. March 2010〕 and in 2010 a follow-on order for more FTINU units was awarded.〔(Honeywell Provides Guidance System For Atlas V Rocket ). Space-travel.com. Retrieved on 2011-11-19.〕 On February 24, 2012, Atlas V lifted its heaviest payload to date into orbit—a military satellite - MUOS-1. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Atlas V」の詳細全文を読む スポンサード リンク
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