Atlas V (pronounced "atlas five") is an expendable launch system in the Atlas rocket family. It was formerly operated by Lockheed Martin and is now operated by United Launch Alliance (ULA), a joint venture with Boeing. 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. 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 and Harlingen, Texas.
Video Atlas V
Vehicle description
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.
Atlas V first stage
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 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, the first stage is a near-redesign. There was no Atlas IV.
The main features of the Atlas V with regards to the Atlas family are:
- The first stage tanks no longer use stainless-steel monocoque "balloon" construction. The tanks are isogrid aluminum and are structurally stable when unpressurized.
- Use of aluminium, 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 "1.5 staging" technique is no longer used, having been discontinued on the Atlas III with the introduction of the Russian 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.
Centaur upper stage
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. As of 2006, 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.
Payload fairing
Atlas V payload fairings are available in two diameters, depending on satellite requirements. The 4.2-meter fairing, originally designed for the Atlas II booster, comes in three different lengths: the original 9-meter-long version, as well as 10-meter and 11-meter versions, first flown respectively on the AV-008/Astra 1KR and AV-004/Inmarsat-4 F1 missions.
A wider 5.4-meter fairing (4.57 meters internally usable) was developed and built by RUAG Space in Switzerland. The RUAG fairing uses carbon fiber composite construction, based on flight-proven hardware from the Ariane 5. Three configurations are manufactured to support the Atlas V: 20.7, 23.4 and 26.5 meters long. While the classic 4-meter fairing covers only the payload, the RUAG fairing is much longer because it fully encloses the Centaur stage, as well as the payload.
Further developments
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. The upgraded FTINU first flew in 2006, and in 2010 a follow-on order for more FTINU units was awarded.
Atlas V CTS (Crew Transportation System)
From 2006 through at least 2014 ULA made proposals and did some design work for a human-rated version of the Atlas V. Atlas V was selected by NASA in late 2014, in conjunction with the Boeing CST-100 space capsule, to be used for human flight from 2018.
The work began as early as 2006, by ULA's predecessor company Lockheed Martin. An agreement between Lockheed and Bigelow Aerospace that year was reported that could lead to commercial private trips to low Earth orbit (LEO).
Beginning in 2010, ULA did design and simulation work to human-rate the Atlas V for carrying passengers. ULA won a 2010 small contract of US$6,700,000 in the first phase of the NASA Commercial Crew Program (CCP) to develop an Emergency Detection System (EDS) for human-rating the Atlas V launch vehicle. As of February 2011, ULA "is still finishing up work on its $6.7-million award... In December ULA carried out a demonstration of its Emergency Detection System ... The company said it received an extension from NASA until April 2011 'to enable us to finish critical timing analyses tasks' for [the] fault coverage analysis work."
NASA solicited proposals for CCP phase 2 in October 2010, under which ULA made a proposal for funding to "finish designing a key safety system for potential commercial crew launches on its Atlas and Delta rocket fleet". While NASA's goal then was to get astronauts to orbit by 2015, ULA President and CEO Michael Gass stated: "I think we need to stretch our goals to have commercial crew service operating by 2014" and committed ULA to meet that schedule if funded. 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 402 configuration, with dual RL10 engines on the Centaur upper stage and no solid rocket boosters.
On July 18, 2011 NASA and ULA announced an agreement on the possibility of certifying the Atlas V to NASA's "human-rating" standards. ULA agreed to provide NASA with data on the Atlas V, while NASA would provide ULA with draft human certification requirements. As of July 2011 Bigelow Aerospace was still considering the use of a human-rated Atlas V for carrying spaceflight participants to its private space station.
In 2011, Sierra Nevada Corporation (SNC) picked the Atlas V to be the booster for its still-under-development Dream Chaser crewed spacecraft. The Dream Chaser is designed to be a crewed vertical-takeoff, horizontal-landing (VTHL) lifting-body spaceplane that will be placed into LEO by an Atlas V, and is a proposed CCDev ISS crew transport vehicle. However, in late 2014 NASA did not select the Dream Chaser to be one of the two vehicles selected under the Commercial Crew competition.
On August 4, 2011 Boeing announced that it would use the Atlas V as the initial launch vehicle for its CST-100 crewed spaceship, intended for both NASA-funded trips to the International Space Station, as well as for private trips to the proposed Bigelow Commercial Space Station. As of August 2011, a three-flight test program had been projected to be completed by 2015, and potentially certify the Atlas V/CST-100 combination for human-spaceflight operations. The first flight was expected to include an Atlas V rocket integrated with an unpiloted CST-100 capsule, to launch from Cape Canaveral's LC-41 in early 2015 into LEO, with the second flight hoped to be an in-flight launch abort system demonstration in the middle of that year, and the test-flight phase expected to culminate with a crewed mission at the end of 2015, carrying two Boeing test-pilot astronauts into LEO and returning them safely. As of 2016, the spacecraft is expected to fly unmanned in June 2018, have a first crewed test flight in August 2018, and ferry two astronauts to the ISS for the first fully operational flight in December 2018.
New solid boosters
In 2015, ULA announced that the Aerojet Rocketdyne-produced AJ-60A solid rocket boosters (SRBs) currently in use on Atlas V will be phased out in favor of new GEM 63 boosters produced by Orbital ATK. A stretched version of this booster will be used on the upcoming Vulcan rocket.
Maps Atlas V
Variants
Each Atlas V booster configuration has a three-digit designation that indicates the features of that configuration. The first digit shows the diameter (in meters) of the payload fairing and always has a value of "4" or "5". The second digit indicates the number of solid rocket boosters attached to the base of the rocket and can range from "0" through "3" with the 4-meter fairing, and "0" through "5" with the 5-meter fairing. As shown on the right, all layouts of solid boosters are asymmetrical. The third digit represents the number of engines on the Centaur stage, either "1" or "2". For example, an Atlas V 552 has a 5-meter fairing, 5 solid rocket boosters, and 2 Centaur engines, whereas an Atlas V 431 has a 4-meter fairing, 3 solid rocket boosters, and 1 Centaur engine. As of 2014, only the single-engine Centaur (SEC) has been used. The first launch using the dual-engine Centaur (DEC) upper stage was planned for November 2016, when an Atlas V 402 will carry the Sierra Nevada Dream Chaser vehicle for its first orbital test flight, but it is not scheduled as of November 2016.
As of June 2015, all versions of the Atlas V, its design and production rights, and intellectual property rights are owned by ULA and Lockheed Martin.
Versions
List date: April 15, 2018 Mass to LEO numbers are at an inclination of 28.5°.
Cost
Since 2016 ULA has provided pricing for the Atlas V through its RocketBuilder website, advertising a base price for each rocket configuration, which ranges from $109 million for the 401 up to $153 million for the 551. Each additional SRB adds an average of $6.8 million to the cost of the rocket. On top of the base price, commercial 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, and processing requirements. These government requirements can add $30-$80 million to the cost of a launch.
Before 2016, ULA did not publicly advertise a price for Atlas V launches, and so cost data was limited to the few for which prices were disclosed. In 2010, NASA contracted with ULA to launch the MAVEN mission on an Atlas V 401 for approximately $187 million. The 2013 cost of this configuration for the Air Force under their block buy of 36 rockets was $164 million. In 2015, the TDRS-M mission aboard this same rocket cost NASA $132.4 million.
The Atlas V historically was not cost-competitive for most commercial launches, where launch costs were about $100 million per satellite to GTO in 2013. The price drop from approximately $180 million to $109 million has been in large part due to competitive pressure that emerged in the launch services marketplace during the early 2010s, with United Launch Alliance CEO Tory Bruno stating that ULA needs at least 2 commercial missions each year in order to stay profitable. Still, the company is not attempting to win these missions on purely lowest purchase price, stating that it "would rather be the best value provider". ULA suggests that customers will have much lower insurance and delay costs because of the high Atlas V reliability and schedule certainty, making overall customer costs close to that of using competitors like the SpaceX Falcon 9.
Atlas V launches
Last updated on April 15, 2018
For planned launches, see List of Atlas launches (2010-2019).
Notable missions
The first payload launched with an Atlas V was the Hot Bird 6 communications satellite launched from Cape Canaveral in a 401 configuration. It carried the communications satellite into geostationary transfer orbit (GTO) on August 21, 2002.
On August 12, 2005, Mars Reconnaissance Orbiter was launched aboard an Atlas V 401 rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station. The Centaur upper stage of the rocket completed its burns over a 56-minute period and placed MRO into an interplanetary transfer orbit towards Mars
On January 19, 2006, New Horizons was launched by a Lockheed Martin Atlas V 551 rocket, with a third stage added to increase the heliocentric (escape) speed. This was the first launch of the Atlas V 551 configuration, which uses five solid rocket boosters, and the first Atlas V with a third stage.
On December 6, 2015, Atlas V lifted its heaviest payload to date into orbit - a 16,517-pound (7,492 kg) Cygnus resupply craft.
On September 8, 2016, the OSIRIS-REx Asteroid Sample Return Mission was launched on an Atlas V rocket in the 411 configuration. It will arrive at the asteroid Bennu in 2018 and return with a sample ranging from 60 grams to 2 kilograms in 2023.
The first four Boeing X-37B spaceplane missions were successfully launched with the Atlas V. The X-37B is a reusable unmanned spacecraft operated by USAF, which is also known as the Orbital Test Vehicle (OTV) that can autonomously conduct landings from orbit to a runway. The first four X-37B launches with the Atlas V were conducted from the Cape Canaveral Air Force Station in Florida with subsequent landings taking place on a 15,000-foot (4,600 m) runway located at Vandenberg Air Force Base in California that was originally designed for Space Shuttle return from orbit operations.
Mission success record
In its more than 75 launches (as of March 2018), starting with its maiden launch in August 2002, Atlas V has had a perfect mission success rate. This is in contrast to the industry failure rate of 5-10%. However, there have been two anomalous flights that - while still successful in their mission - have prompted a grounding of the Atlas fleet while investigations determined the root cause of their problems.
The first anomalous event in the use of the Atlas V launch system occurred on 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. 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. Replacing the valve led to a delay in the next Atlas V launch. However, the customer (the National Reconnaissance Office) categorized the mission as a success.
A flight on March 23, 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 utilizing its fuel reserves to make up for the shortfall from the first stage. This longer burn cut short a later Centaur disposal burn. 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.
Proposed development options
Replacement for the RD-180 engine
Geopolitical and US political considerations in 2014 led to an effort by ULA to consider the possible replacement of the Russian-supplied RD-180 engine used on the first-stage booster of the Atlas V. Formal study contracts were issued in June 2014 to a number of US rocket-engine suppliers. The results of those studies have led to decisions by ULA to develop a new launch vehicle to replace the Atlas V and Delta IV existing fleet.
The Aerojet AR1 rocket engine under development as of 2017, is a backup plan to the successor rocket Vulcan, to re-engine the Atlas V. In addition to the ULA backup plan, a consortium of companies including Aerojet and Dynetics seek license production or rights to the Atlas V to manufacture it using the AR1 engine in place of the RD-180. This proposal has been declined by ULA. The private company Blue Origin is developing the BE-4 LOX/methane engine as an RD-180 replacement.
Atlas V Heavy
In 2006, ULA offered an Atlas V Heavy option that would use three Common Core Booster (CCB) stages strapped together to lift a 29,400 kg payload to low Earth orbit. 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. The lifting capability of the proposed rocket was to be roughly equivalent to the Delta IV Heavy, which utilizes RS-68 engines developed and produced domestically by Aerojet Rocketdyne.
A 2006 report, prepared by the RAND Corporation for the Office of the Secretary of Defense, stated that Lockheed Martin had decided not to develop an Atlas V heavy-lift vehicle (HLV). The report recommended for the Air Force and the National Reconnaissance Office 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 U.S. development of an RD-180 replacement".
As of March 2010, ULA stated that the Atlas V Heavy configuration could be available to customers 30 months from the date of order.
In March 2015, Bruno confirmed on Twitter that the Atlas V Heavy will not be developed, instead they would be focusing on the Next Gen Launch System (Vulcan).
Atlas Phase 2
With the merger of Boeing and Lockheed Martin space operations into United Launch Alliance in the mid-2000s, the Atlas V program became able to share the tooling and processes for 5-meter-diameter stages used on Delta IV. This led to a concept being put forth to combine Delta IV production processes into a new Atlas design: the "Atlas Phase 2". If the first stage were to be 5 meters in diameter, such a stage could accept dual RD-180 engines. The conceptual heavy-lift vehicle was known as Atlas Phase 2 or "PH2".
An Atlas V PH2-Heavy (three 5 m stages in parallel; six RD-180s) along with Shuttle-derived, Ares V and Ares V Lite, was considered as a theoretically possible heavy lifter for use in future space missions in the Augustine Report. If built, the Atlas PH2 Heavy was projected to be able to launch a payload mass of approximately 70 metric tons into an orbit of 28.5° inclination. None of the Atlas V Phase 2 proposals reached development.
GX rocket
The Atlas V Common Core Booster was to have been used as the first stage of the joint US-Japanese GX rocket, which was scheduled to make its maiden flight in 2012. GX launches would have been from the Atlas V launch complex at Vandenberg AFB, SLC-3E.
In December 2009, the Japanese government decided to cancel the GX project.
Successor
The Vulcan rocket is the intended replacement for all three of ULA's currently flying rockets, the Atlas V, Delta II, and Delta IV.
In September 2014, ULA announced that it has entered into a partnership with Blue Origin to develop the BE-4 LOX/methane engine to replace the RD-180 on a new first-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 must be developed. This booster will be derived from the first-stage tankage of the Delta IV, using two of the 2,400-kilonewton (550,000 lbf)-thrust BE-4 engines. The engine is already in its third year of development by Blue Origin, and ULA expects the new stage and engine to start flying no earlier than 2019.
Vulcan will initially use the same Centaur upper stage as on Atlas V, later to be upgraded to ACES. It will also use a variable number of optional solid rocket boosters, called the GEM 63XL, derived from the new solid boosters planned for Atlas V.
Photo gallery
See also
References
External links
- ULA Atlas V data sheets
- Atlas 500 series cutaway
- Atlas 400 series cutaway
- ULA Atlas V RocketBuilder
- Lockheed Martin: Atlas Launch Vehicles
- Encyclopedia Astronautica: Atlas V
- Space Launch Report: Atlas 5 Data Sheet
Source of the article : Wikipedia
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