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Atlas V
Launch of the Mars Reconnaissance Orbiter, 11:43:00 AM GMT August 12, 2005 on the first Atlas V rocket used by NASA. The rocket is in the 401 configuration.
Fact sheet
Function	EELV/Medium-heavy launch vehicle
Manufacturer	United Launch Alliance
Country of origin	USA
Size
Height	58.3 m (191.2 ft)
Diameter	3.81 m (12.49 ft)
Mass	546,700 kg (1,205,200 lb)
Stages	2
Capacity
Payload to LEO	10,300 - 20,050 kg
Payload to GTO	4,100 - 8,200 kg
Launch History
Status	Active
Launch sites	LC-41, CCAFS SLC-3W, Vandenberg AFB
Total launches	12 For breakdown by variant, see text
Successes	11
Partial failures	1 (401)[1]
Maiden flight	21 August 2002
Notable payloads	Mars Reconnaissance Orbiter New Horizons
Boosters (Not Heavy) - Aerojet
No boosters	1 to 5 (see text)
Engines	1 Solid
Thrust	1,270 kN (285,500 lbf)
Specific impulse	275 sec
Burn time	94 seconds
Fuel	Solid
Boosters (Atlas V Heavy (5HX)) - Atlas CCB
No boosters	2
Engines	1 RD-180
Thrust	4,152 kN (933,406 lbf)
Specific impulse	311 sec
Burn time	253 seconds
Fuel	RP-1/LOX
First Stage - Atlas CCB
Engines	1 RD-180
Thrust	4,152 kN (933,406 lbf)
Specific impulse	311 sec
Burn time	253 seconds
Fuel	RP-1/LOX
Second Stage (Atlas V XX1) - Centaur
Engines	1 RL-10A
Thrust	99.2 kN (22,290 lbf)
Specific impulse	451 sec
Burn time	842 seconds
Fuel	LH2/LOX
Second Stage (Atlas V XX2) - Centaur
Engines	2 RL-10A
Thrust	147 kN (41,592 lbf)
Specific impulse	449 sec
Burn time	421 seconds
Fuel	LH2/LOX

The Atlas V rocket is an expendable launch vehicle formerly built by Lockheed Martin and now built by the Lockheed Martin-Boeing joint venture United Launch Alliance. Aerojet develops and manufactures the Atlas V boosters. The rocket, built in Decatur, Alabama, consists of a first stage powered by kerosene and liquid oxygen, which uses a Russian made RD-180 engine, and a liquid hydrogen–liquid oxygen powered Centaur upper stage. Some configurations also use strap-on booster rockets. Together these components are referred to as the Atlas launch vehicle.

In its 11 launches, from its maiden launch in August 2002 to October 2007, the Atlas V had a success rate of 91%. The only failure occurred in June 15, 2007, when the engine in the Centaur upper stage of an Atlas V shut down early, leaving its payload -- a pair of NRO L-30 ocean surveillance satellites -- in a lower than intended orbit.^[2] The cause of the anomaly was traced to a leaky valve. Replacing the valve led to a delay in an upcoming Atlas V launch.^[3]

The Atlas V is the newest member of the Atlas family, and is a direct descendant of the previous Atlas II and especially the Atlas III vehicles. Most propulsion, avionic and structural elements are either identical to or straightforward derivations of those used on the previous vehicles.

The most obvious external change is to the first stage tanks, which no longer use 10 foot diameter, stainless steel monocoque, common intermediate bulkhead "balloon" construction nor the '1.5 staging' technique which jettisoned two engines in mid-flight but left a third burning all the way from the ground to orbit, but instead use a 12.5 foot diameter welded aluminum alloy construction first stage much like that of the Titan family of vehicles or the Space Shuttle external tank.

The Atlas V was developed by Lockheed Martin Commercial Launch Services as part of the US Air Force Evolved Expendable Launch Vehicle (EELV) program. The term expendable launch vehicle means it is only used once. Launches are from Space Launch Complex 41 at Cape Canaveral Air Force Station. In addition, Space Launch Complex 3 East at Vandenberg Air Force Base is being prepared for future polar launches.

The first Atlas V was launched on August 21, 2002. Nine Atlas V launches to date have been completely successful, one was rated partial failure. 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 Aerojet made strap-on solid rocket boosters. The CCB is 12.5 ft (3.8 m) in diameter by 106.6 ft (32.5 m) long and uses 627,105 lb (284,450 kg) of liquid oxygen and RP-1 rocket fuel propellants. The booster operates for about four minutes, providing about 4 meganewtons (860,000 lbf) of thrust at start.

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) and is powered by either one or two Pratt & Whitney RL10A-4-2 engines, each engine developing a thrust of 99.2 kN (22,300 lbf). Operational and reliability upgrades are 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. A subsequent third burn following a multi-hour coast can permit direct injection of payloads into geostationary orbit. The Centaur vehicle has the highest proportion of burnable propellant relative to total mass of any modern 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. An upgrade to a Fault Tolerant INU (FTINU) was recently made to enhance mission reliability for Atlas vehicles.

An Atlas V 551 with the New Horizons Deep Space Probe launches from Lauch Pad 41 in Cape Canaveral.

The Atlas V-Heavy or HLV configuration is available 30 months from order.^{[citation needed]} It would use three CCB stages strapped together to provide the capability necessary to lift the heaviest spacecraft. Approximately 95% of the hardware required for the Atlas HLV has already been flown on the Atlas V single core vehicles.

The Atlas V has two general payload fairing sizes. The classic 4-meter fairing, used since the Atlas II, comes in regular and slightly stretched versions (see AV-004/Inmarsat 4-F1 launch), and Lockheed Martin introduced a 5-meter (4.57 meters usable) payload fairing developed and built by Contraves Space (now Oerlikon Space[1]) in Switzerland. The Contraves fairing is a composite design and is based on flight proven hardware. Three configurations will be manufactured to support Atlas V. The short and medium length configurations will be used on the Atlas V 500 series. The long configuration will be used on the Atlas V-Heavy. The classic fairing covers only the payload, leaving the Centaur stage exposed to open air. With the Contraves fairing, the Centaur is enclosed within the fairing as well as the payload.

Core stage of an Atlas V being raised to a vertical position.

Each Atlas booster has a three digit version designation that is determined by the features of the rocket. The first digit is the diameter (in meters) of the nosecone fairing, and is always either four or five. The second digit is the number of solid rocket boosters attached to the base of the rocket, and can number anywhere from zero through three with the 4-m fairing and zero through five with the 5-m fairing. The third digit is the number of engines on the Centaur stage, either one or two. Single-engine Centaurs (SEC) are typically used for satellites going to geostationary transfer orbit or reaching escape velocity. Dual engine Centaurs (DEC) are typically used for satellites reaching low Earth orbit.

For example, if the Atlas V version is 552, this means that the fairing is five meters, has five solid rocket boosters, and has two Centaur engines.

If the Atlas V version is 431, this means that the fairing is four meters, has three solid rocket boosters, and has a single Centaur engine.

Comparable rockets: Delta IV - Ariane 5 - Chang Zheng 5 - Angara - Proton - Falcon 9

An agreement between Lockheed and Bigelow Aerospace in September 2006 could lead to a human-rated version of the Atlas V to tap into the potential space tourism market.^[4]

Versions:

The MRO spacecraft lauches on August the 12. 2005 at 11:43 UTC to the Planet Mars onboard an Atlas V 401 Launch Vehicle.

List Date: June 16, 2007

For more details on this topic, see Atlas V Launches.

List Date: June 2007

List Date: August 1, 2007

• Comparison of heavy lift launch systems

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Atlas

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