Atlas V^[a] is anexpendable launch system and the fifth major version in theAtlas launch vehicle family. It was designed byLockheed Martin and has been operated byUnited Launch Alliance (ULA)^[b] since 2006. It is used forDoD, NASA, and commercial payloads. It is America's longest-serving active rocket. After 87 launches, in August 2021 ULA announced that Atlas V would be retired, and all 29 remaining launches had been sold. As of July 2024^[update], 15 launches remain. Production ceased in 2024.^[10] Other future ULA launches will use theVulcan Centaur rocket.^[11]

Atlas V

Launch of an Atlas V 401 carrying theLunar Reconnaissance Orbiter andLCROSS space probes on 18 June 2009.
Function	Medium-lift launch vehicle
Manufacturer	United Launch Alliance
Country of origin	United States
Cost per launch	US$110–153 million (2016)[1]
Size
Height	Up to 58.3 m (191 ft)
Diameter	3.81 m (12.5 ft)
Mass	590,000 kg (1,300,000 lb)
Stages	2
Capacity
Payload toLEO
Orbital inclination	28.70°
Mass	8,210–18,850 kg (18,100–41,560 lb)[2]
Payload toGTO
Mass	4,750–8,900 kg (10,470–19,620 lb)
Associated rockets
Family	Atlas
Based on	Atlas III
Comparable	Delta IV Falcon 9 Long March 3B Proton-M Saturn IB
Launch history
Status	Active, retiring
Launch sites	Cape Canaveral,SLC-41 Vandenberg,SLC-3 (until 2022)
Total launches	101[3][4][5] 401: 41 411: 6 421: 9 431: 3 501: 8 511: 1 521: 2 531: 5 541: 9 551: 14 N22: 3
Success(es)	100 401: 40 411: 6 421: 9 431: 3 501: 8 511: 1 521: 2 531: 5 541: 9 551: 14 N22: 3
Partial failure(s)	15 June 2007
First flight	21 August 2002 (Hot Bird 6)
Last flight	30 July 2024 (USSF-51)
Boosters –AJ-60A[6]
No. boosters	0 to 5
Height	17 m (56 ft)[6]
Diameter	1.6 m (5 ft 3 in)
Gross mass	46,697 kg (102,949 lb)
Propellant mass	42,630 kg (93,980 lb)[7]
Maximum thrust	1,688.4 kN (379,600 lbf)
Specific impulse	279.3 s (2.739 km/s)
Burn time	94 seconds
Propellant	AP /HTPB /Al
Boosters –GEM 63[8][9]
No. boosters	0 to 5
Height	20.1 m (66 ft)[8]
Diameter	1.6 m (63 in)
Gross mass	49,300 kg (108,700 lb)
Propellant mass	44,200 kg (97,400 lb)
Maximum thrust	1,663 kN (374,000 lbf)
Burn time	94 seconds
Propellant	AP /HTPB /Al
First stage –Atlas CCB
Height	32.46 m (106.5 ft)
Diameter	3.81 m (12.5 ft)
Empty mass	21,054 kg (46,416 lb)
Propellant mass	284,089 kg (626,309 lb)
Powered by	1 ×RD-180
Maximum thrust	SL: 3,827 kN (860,000 lbf) vac: 4,152 kN (933,000 lbf)
Specific impulse	SL: 311.3 s (3.053 km/s) vac: 337.8 s (3.313 km/s)
Burn time	253 seconds
Propellant	RP-1 /LOX
Second stage –Centaur III
Height	12.68 m (41.6 ft)
Diameter	3.05 m (10.0 ft)
Empty mass	2,316 kg (5,106 lb)
Propellant mass	20,830 kg (45,920 lb)
Powered by	1 ×RL10A,2 × RL10A or1 ×RL10C
Maximum thrust	99.2 kN (22,300 lbf) (RL10A)
Specific impulse	450.5 s (4.418 km/s) (RL10A)
Burn time	842 seconds (RL10A)
Propellant	LH2 /LOX
[edit on Wikidata]

Each Atlas V launch vehicle consists of two main stages. Thefirst stage is powered by a single RussianRD-180 engine burningkerosene andliquid oxygen. TheCentaur upper stage is powered by one or two AmericanRL10 engine(s) manufactured byAerojet Rocketdyne and burnsliquid hydrogen andliquid oxygen.Strap-onsolid rocket boosters (SRBs) are used in many configurations.AJ-60A SRBs were used originally, but they were replaced in November 2020 byGraphite-Epoxy Motor (GEM 63) SRBs for all except Starliner launches. The standardpayload fairings are 4.2 or 5.4 m (14 or 18 ft) in diameter with various lengths.^[12]

The Atlas V was developed byLockheed Martin Commercial Launch Services (LMCLS) as part of theU.S. Air ForceEvolved Expendable Launch Vehicle (EELV) program and made its inaugural flight on 21 August 2002. The vehicle operates fromSLC-41 atCape Canaveral Space Force Station (CCSFS). It also operated fromSLC-3E atVandenberg Space Force Base until 2022. LMCLS continued to market the Atlas V to commercial customers worldwide until January 2018, whenUnited Launch Alliance (ULA) assumed control of commercial marketing and sales.^[13][14]

The Atlas V first stage, theCommon Core Booster (not to be confused with the Delta IV'sCommon Booster Core), is 3.8 m (12 ft) in diameter and 32.5 m (107 ft) in length. It is powered by one RussianNPO EnergomashRD-180 main engine burning 284,450 kg (627,100 lb) of liquid oxygen andRP-1. The booster operates for about four minutes, providing about 4 MN (900,000 lb_f) of thrust.^[15] Thrust can be augmented with up to fiveAerojetAJ-60A orNorthrop Grumman GEM 63 strap-onsolid rocket boosters, each providing an additional 1.27 MN (290,000 lb_f) of thrust for 94 seconds.

The main differences between the Atlas V and earlierAtlas I andII family launch vehicles are:

• The first stage tanks no longer usestainless steelmonocoque pressure stabilized "balloon" construction. The tanks areisogridaluminum and are structurally stable when unpressurized.^[15]
• Accommodation points for parallel stages, both smaller solids and identical liquids, are built into first-stage structures.^[15]
• The"1.5 staging" technique is no longer used, having been discontinued on theAtlas III with the introduction of the Russian RD-180 engine.^[15]
• The main-stage diameter increased from 3.0 to 3.7 m (9.8 to 12.1 ft).^[16]

TheCentaur upper stage uses a pressure-stabilized propellant-tank design andcryogenic propellants. The Centaur stage for Atlas V is stretched 1.7 m (5 ft 7 in) relative to theAtlas 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 lb_f). Theinertial 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 intolow Earth parking orbit, followed by a coast period and then insertion intoGTO.^[17] A subsequent third burn following a multi-hour coast can permit direct injection of payloads intogeostationary orbit.^{[citation needed]}

As of 2006^[update], 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.^[18]

Atlas V payload fairings are available in two diameters, depending on satellite requirements. The 4.2 m (14 ft) diameter fairing,^[19] originally designed for theAtlas II booster, comes in three different lengths: the original 9 m (30 ft) version and extended 10 and 11 m (33 and 36 ft) versions, first flown respectively on the AV-008/Astra 1KR and AV-004/Inmarsat-4 F1 missions. Fairings of up to 7.2 m (24 ft) diameter and 32.3 m (106 ft) length have been considered but were never implemented.^[12]

A 5.4 m (18 ft) diameter fairing, with an internally usable diameter of 4.57 m (15.0 ft), was developed and built byRUAG Space^[20] inSwitzerland. The RUAG fairing usescarbon fiber composite construction and is based on a similar flight-proven fairing for theAriane 5. Three configurations are manufactured to support the Atlas V: 20.7 m (68 ft), 23.4 m (77 ft), and 26.5 m (87 ft) long.^[20] While the classic 4.2 m (14 ft) fairing covers only the payload, the RUAG fairing is much longer and fully encloses both the Centaur upper stage and the payload.^[21]

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 aFault TolerantInertial Navigation Unit (FTINU) started in 2001 to enhance mission reliability for Atlas vehicles by replacing the earlier non-redundant navigation and computing equipment with a fault-tolerant unit.^[22] The upgraded FTINU first flew in 2006,^[23] and in 2010 a follow-on order for more FTINU units was awarded.^[24]

In 2015, ULA announced that the Aerojet Rocketdyne-producedAJ-60A solid rocket boosters (SRBs) then in use on Atlas V would be superseded by newGEM 63 boosters produced byNorthrop Grumman Innovation Systems. The extended GEM 63XL boosters will also be used on theVulcan Centaur launch vehicle that will replace the Atlas V.^[25] The first Atlas V launch with GEM 63 boosters happened on 13 November 2020.^[26]

Proposals and design work tohuman-rate the Atlas V began as early as 2006, with ULA's parent companyLockheed Martin reporting an agreement withBigelow Aerospace that was intended to lead to commercialprivate trips tolow Earth orbit (LEO).^[27]

Human-rating design and simulation work began in earnest in 2010, with the award of US$6.7 million in the first phase of theNASACommercial Crew Program (CCP) to develop anEmergency Detection System (EDS).^[28]

As of February 2011, ULA had received an extension to April 2011 from NASA and was finishing up work on the EDS.^[29]

NASA solicited proposals for CCP phase 2 in October 2010, and ULA proposed to complete design work on the EDS. At the time, NASA's goal was to get astronauts to orbit by 2015. Then-ULA President and CEO Michael Gass stated that a schedule acceleration to 2014 was possible if funded.^[30] Other than the addition of the Emergency Detection System, no major changes were expected to the Atlas V rocket, but ground infrastructure modifications were planned. The most likely candidate for the human-rating was the N02 configuration, with no fairing, no solid rocket boosters, and dual RL10 engines on the Centaur upper stage.^[30]

On 18 July 2011, NASA and ULA announced an agreement on the possibility of certifying the Atlas V to NASA's standards for human spaceflight.^[31] ULA agreed to provide NASA with data on the Atlas V, while NASA would provide ULA with draft human certification requirements.^[31] In 2011, the human-rated Atlas V was also still under consideration to carry spaceflight participants to the proposedBigelow Commercial Space Station.^[32]

In 2011,Sierra Nevada Corporation (SNC) picked the Atlas V to be the booster for its still-under-developmentDream Chaser crewedspaceplane.^[33] The Dream Chaser was intended to launch on an Atlas V, fly a crew to the ISS, and land horizontally following alifting-body reentry.^[33] However, in late 2014NASA did not select the Dream Chaser to be one of the two vehicles selected under theCommercial Crew competition.

On 4 August 2011,Boeing announced that it would use the Atlas V as the initial launch vehicle for itsCST-100 crew capsule. CST-100 will take NASA astronauts to theInternational Space Station (ISS) and was also intended to service the proposedBigelow Commercial Space Station.^[34][35] A three-flight test program was projected to be completed by 2015, certifying the Atlas V/CST-100 combination for human spaceflight operations.^[35] The first flight was expected to include an Atlas V rocket integrated with an uncrewed CST-100 capsule,^[34] the second flight an in-flight launch abort system demonstration in the middle of that year,^[35] and the third flight a crewed mission carrying two Boeing test-pilot astronauts into LEO and returning them safely at the end of 2015.^[35] These plans were delayed by many years and morphed along the way so that in the end, the first orbital test flight with no crew materialized in 2019, but it was a failure and needed to be reflown in 2022, the in-flight launch abort system test flight did not materialize, and the third flight, a crewed orbital test flight with two astronauts (in the end NASA's, not Boeing's astronauts) materialized in June 2024 asBoeing Crewed Flight Test. The launch abort system was tested in 2019 in theBoeing Pad Abort Test. The spacecraft launched from a test stand, not from an Atlas V.

In 2014,NASA selected theBoeing Starliner CST-100 spacecraft as part of theCommercial Crew Program. Atlas V is the launch vehicle for Starliner. The first launch of an uncrewed Starliner, theBoeing OFT mission, occurred atop a human-rated Atlas V on the morning of 20 December 2019; the mission failed to meet goals due to a spacecraft failure, though the Atlas V launcher performed well.^[36][37] In 2022, an Atlas V launched an uncrewed Starliner capsule for the second time onBoe-OFT 2 mission; the mission was a success.^[38][39]

In June 2024, onBoe-CFT mission, Atlas V carried humans into space for the first time, launching two NASA astronauts to the ISS.^[40][41]

Amazon selected the Atlas V to launch some of the satellites forProject Kuiper. Project Kuiper will offer ahigh-speedsatellite internet constellation service. The contract signed with Amazon is for all nine remaining available Atlas V rockets. Project Kuiper aims to put thousands of satellites into orbit. ULA is Amazon's first launch provider.^[42] Two Kuiper test satellites were launched on Atlas V in 2023 because their originally-contracted launch vehicles were not available on time. The remaining eight Atlas V Kuiper launches will each carry a full payload of Kuiper satellites. Most of the Kuiper constellation will use other launch vehicles.

Each Atlas V booster configuration has a three-digit designation.

The first digit shows the diameter (in meters) of the payload fairing and has a value of "4" or "5" for fairing launches and "N" for crew capsule launches (as no payload fairing is used).

The second digit indicates the number of solid rocket boosters (SRBs) attached to the core of the launch vehicle and can range from "0" through "3" with the 4 m (13 ft) fairing, and "0" through "5" with the 5 m (16 ft) fairing. As seen in the first image, all SRB layouts are asymmetrical.

The third digit represents the number of engines on the Centaur stage, either "1" or "2". All of the configurations use theSingle Engine Centaur, except for the "N22" which is only used onStarliner crew capsule missions, and usesDual Engine Centaur.

Atlas V has flown in eleven configurations:^[43]

  Active  Retired

Before 2016, pricing information for Atlas V launches was limited. In 2010, NASA contracted with ULA to launch theMAVEN mission on an Atlas V 401 for approximately US$187 million.^[48] The 2013 cost of this configuration for the U.S. Air Force under their block buy of 36 launch vehicles was US$164 million.^[49] In 2015, theTDRS-M launch on an Atlas 401 cost NASA US$132.4 million.^[50]

Starting in 2016, ULA provided pricing for the Atlas V through its RocketBuilder website, advertising a base price for each launch vehicle configuration, which ranges from US$109 million for the 401 up to US$153 million for the 551.^[1] Each additional SRB adds an average of US$6.8 million to the cost of the launch vehicle. Customers can also choose to purchase larger payload fairings or additional launch service options. NASA and Air Force launch costs are often higher than equivalent commercial missions due to additional government accounting, analysis, processing, and mission assurance requirements, which can add US$30–80 million to the cost of a launch.^[51]

In 2013, launch costs for commercial satellites toGTO averaged about US$100 million, significantly lower than historic Atlas V pricing.^[52] However, after the rise ofreusable rockets, the price of an Atlas V [401] has dropped from approximately US$180 million to US$109 million,^[53] in large part due tocompetitive pressure that emerged in the launch services marketplace during the early 2010s. ULA CEOTory Bruno stated in 2016 that ULA needs at least two commercial missions each year in order to stay profitable going forward.^[54] ULA is not attempting to win these missions on purely lowest purchase price, stating that it "would rather be the bestvalue provider".^[55] In 2016, ULA suggested that customers would have much lowerinsurance anddelay costs because of the high Atlas V reliability and schedule certainty, making overall customer costs close to that of using competitors like theSpaceXFalcon 9.^[56]

In 2006, ULA offered an Atlas V Heavy option that would use threeCommon Core Booster (CCB) stages strapped together to lift a 29,400 kg (64,800 lb) payload tolow Earth orbit.^[57] ULA stated at the time that 95% of the hardware required for the Atlas V Heavy has already been flown on the Atlas V single-core vehicles.^[12] The lifting capability of the proposed launch vehicle was to be roughly equivalent to theDelta IV Heavy,^[12] which usedRS-68 engines developed and produced domestically by Aerojet Rocketdyne.

A 2006 report, prepared by theRAND Corporation for theOffice of the Secretary of Defense, stated that Lockheed Martin had decided not to develop an Atlas V heavy-lift vehicle (HLV).^[58] The report recommended for the U.S. Air Force and theNational Reconnaissance Office (NRO) to "determine the necessity of an EELV heavy-lift variant, including development of an Atlas V Heavy", and to "resolve the RD-180 issue, including coproduction,stockpile, or United States development of an RD-180 replacement".^[59]

In 2010, ULA stated that the Atlas V Heavy variant could be available to customers 30 months from the date of order.^[12]

Atlas V PH2

In late 2006, the Atlas V program gained access to the tooling and processes for 5-meter-diameter stages used onDelta IV when Boeing and Lockheed Martin space operations were merged into theUnited Launch Alliance. This led to a proposal to combine the 5-meter-diameter Delta IV tankage production processes with dual RD-180 engines, resulting in theAtlas Phase 2.

AnAtlas V PH2-Heavy consisting of three 5-meter stages in parallel with six RD-180s was considered in theAugustine Report as a possible heavy lifter for use in future space missions, as well as theShuttle-derivedAres V andAres V Lite.^[60] If built, the Atlas PH2-Heavy was projected to be able to launch a payload mass of approximately 70 t (69 long tons; 77 short tons) into an orbit of 28.5°inclination.^[60]

Booster for GX rocket

The Atlas V Common Core Booster was to have been used as the first stage of the joint US-JapaneseGX rocket, which was scheduled to make its first flight in 2012.^[61] GX launches would have been from the Atlas V launch complex at Vandenberg Air Force Base,SLC-3E. However, the Japanese government decided to cancel the GX project in December 2009.^[62]

Out-licensing rejected by ULA

In May 2015, a consortium of companies, includingAerojet andDynetics, sought to license the production or manufacturing rights to the Atlas V using theAerojet Rocketdyne AR1 engine in place of the RD-180. The proposal was rejected by ULA.^[63]

ULA has stopped selling the Atlas V. It will fly 15 more launches.^[182]

For planned launches, seeList of Atlas launches (2020–2029).

The first payload, theHot Bird 6 communications satellite, was launched to geostationary transfer orbit (GTO) on 21 August 2002 by an Atlas V 401.^[183]

On 12 August 2005, theMars Reconnaissance Orbiter was launched aboard an Atlas V 401 launch vehicle fromSpace Launch Complex 41 atCape Canaveral Air Force Station (CCAFS). TheCentaur upper stage of the launch vehicle completed its burns over a 56-minute period and placed MRO into aninterplanetary transfer orbit towards Mars.^[69]

On 19 January 2006,New Horizons was launched by a Lockheed Martin Atlas V 551 rocket. A third stage was added to increase the heliocentric (escape) speed. This was the first launch of the Atlas V 551 configuration with five solid rocket boosters, and the first Atlas V with a third stage.^[184]

On 6 December 2015, Atlas V lifted its heaviest payload to date into orbit – a 16,517 lb (7,492 kg)Cygnus resupply craft.^[185]

On 8 September 2016, theOSIRIS-REx Asteroid Sample Return Mission was launched on an Atlas V 411 launch vehicle. It arrived at the asteroid Bennu in December 2018 and departed back to Earth in May 2021 to arrive September 2022 at with a sample ranging from 60 grams to 2 kilograms in 2023.^[186]

FiveBoeing X-37Bspaceplane missions were successfully launched with the Atlas V. The flights are launched on Atlas V 501s fromCape Canaveral Space Force Station in Florida. The X-37B, also known as the Orbital Test Vehicle (OTV), is a reusable robotic spacecraft operated byUSAF that can autonomously conduct landings from orbit to a runway.^[187] The firstVandenberg Air Force Base landing at theSpace Shuttle 15,000 ft (4,600 m) runway occurred in December 2010.^[188] Landings occur at both Vandenberg and Cape Canaveral depending on mission requirements.^[187]

On 20 December 2019, the firstStarliner crew capsule was launched inBoe-OFT un-crewed test flight. The Atlas Vlaunch vehicle performed flawlessly but an anomaly with the spacecraft left it in a wrong orbit. The orbit was too low to reach the flight's destination ofISS, and the mission was subsequently cut short.

In its 100 launches (as of June 2024), starting with its first launch in August 2002, Atlas V has achieved a 100% mission success rate and a 99% vehicle success rate.^[189]

The first anomalous event in the use of the Atlas V launch system occurred on 15 June 2007, when the engine in the Centaur upper stage of an Atlas V shut down early, leaving its payload – a pair ofNROL-30 oceansurveillance satellites – in a lower than intended orbit. The cause of the anomaly was traced to a leaky valve, which allowed fuel to leak during the coast between the first and second burns. The resulting lack of fuel caused the second burn to terminate 4 seconds early.^[190] Replacing the valve led to a delay in the next Atlas V launch.^[78] However, the customer (theNational Reconnaissance Office) categorized the mission as a success.^[191][192]

A flight on 23 March 2016, suffered an underperformance anomaly on the first-stage burn and shut down 5 seconds early. The Centaur proceeded to boost the Orbital Cygnus payload, the heaviest on an Atlas to date, into the intended orbit by using its fuel reserves to make up for the shortfall from the first stage. This longer burn cut short a later Centaur disposal burn.^[193] An investigation of the incident revealed that this anomaly was due to a fault in the main engine mixture-ratio supply valve, which restricted the flow of fuel to the engine. The investigation and subsequent examination of the valves on upcoming missions led to a delay of the next several launches.^[194]

In 2014, geopolitical andU.S.political considerations because of theRussian annexation of Crimea led to an effort to replace the Russian-suppliedNPO EnergomashRD-180 engine used on the first-stage booster of the Atlas V. Formal study contracts were issued in June 2014 to a number of U.S. rocket-engine suppliers.^[195] The results of those studies led to a decision by ULA to develop the newVulcan Centaur launch vehicle to replace the existing Atlas V and the now retiredDelta IV.^[196]

In September 2014, ULA announced a partnership withBlue Origin to develop theBE-4LOX/methane engine to replace the RD-180 on a newfirst-stage booster. As the Atlas V core is designed around RP-1 fuel and cannot be retrofitted to use a methane-fueled engine, a new first stage is being developed. This booster will have the same first-stage tankage diameter as the Delta IV and will be powered by two 2,400 kN (540,000 lb_f) thrust BE-4 engines.^{[195][197][198]} The engine was already in its third year of development by Blue Origin, and ULA expected the new stage and engine to start flying no earlier than 2019.

Vulcan was initially planned to use the sameCentaur upper stage as on Atlas V, and later to upgrade toACES, howeverACES is no longer being pursued, andCentaur V will be used instead.^[199] It will also use a variable number of optional solid rocket boosters, called theGEM 63XL, derived from the new solid boosters planned for Atlas V.^[25]

As of 2017, theAerojet Rocketdyne AR1 rocket engine was under development as a backup plan for Vulcan.^[200]

The first Vulcan successfully launched on 8 January 2024.^[201][202]

In August 2021, ULA announced that they are no longer selling launches on the Atlas V and they would fulfill their 29 existing launch contracts.^[11] They made a final purchase of the RD-180 motors they needed and the last of those motors were delivered in April 2021. The last launch will occur "some time in the mid-2020s".^[11] As of July 2024^[update], fourteen missions have flown since the announcement,^[c] and fifteen launches remain.

•  
  Core stage of an Atlas V being raised to a vertical position.
•  
  X-37B OTV-1 (Orbital Test Vehicle) being encased in its payload fairing for its 22 April 2010, launch.
•  
  An Atlas V 541 is moved to the launch pad.
•  
  Atlas V 401 on launch pad
•  
  Atlas V ignition
•  
  An Atlas V 551 with theNew Horizons probe launches from Launch Pad 41 inCape Canaveral.

• ULA Atlas V data sheets
  • Atlas 500 series cutaway
  • Atlas 400 series cutaway
• ULA Atlas V RocketBuilder
• Lockheed Martin: Atlas Launch Vehicles