Atlas V

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An Atlas V (551) with New Horizons on board on a movable launch platform from launch complex 41. Two of the five solid fuel boosters can be seen in this photo.
An Atlas V (551) launches the Juno spacecraft

In the Atlas V is a US - launcher for medium to heavy payloads. It is the most modern member of the Atlas rocket family. The Atlas V was developed and initially built by Lockheed Martin ; the maiden flight was successfully completed in August 2002. The launches were marketed by the US-Russian company International Launch Services until the end of 2006 . Thereafter this deal was transferred to the United Launch Alliance , a joint venture between Lockheed Martin and Boeing, transfer. Since this restructuring, the Atlas V has been offered almost exclusively for orders from the US government, as the commercial business had proven to be unprofitable in previous years. Thus today the rocket mainly transports military satellites as well as space probes and spaceships on behalf of NASA . The most famous payloads include the Mars Reconnaissance Orbiter , New Horizons , the Boeing X-37 space glider and the Mars rovers Curiosity and Perseverance .

One of the strengths of the Atlas V is its extremely high starting reliability. To date, there has not been a single false start. Another feature is the rocket's highly modular design; a total of 19 different variants are possible. It is also worth mentioning the use of an engine developed and produced in Russia in the main stage. In addition to economic considerations, this engine choice meant that the Atlas V was to be replaced by the successor model Vulcan in the years to come. From 2022 onwards, the US military will no longer be allowed to commission satellite launches that would use a Russian engine.



The development of the Atlas V began with a tender by the US government in 1994. A new carrier system called Evolved Expendable Launch Vehicle (EELV) was to be developed and built. Above all, the new rocket should transport medium to heavy payloads into orbit much more cheaply than before, especially in comparison to the Titan IV or the even more cost-intensive space shuttle . Similar to the European Ariane 4 , its modular structure should also be able to transport a wide range of payloads at internationally competitive prices. All major US aerospace companies responded to the tender: McDonnell Douglas with a further development of the Delta series, Lockheed Martin with an improved Atlas variant, and Boeing and Alliant Technologies with completely new designs (including the SSME engine as a basis). When Boeing bought McDonnell Douglas in 1996, they also took over the offered Delta development. The Air Force provided all four applicants with US $ 30 million each to finance the rough draft phase.

Subsequently, both Boeing and Lockheed Martin were awarded the contract to develop the Delta IV and the Atlas V , respectively . In this second phase, both companies received an additional $ 60 million to revise their submitted concepts and begin detailed planning.

In October 1998 the third and final phase began, in which both carriers were developed to readiness for use. Linked to this was the firm commitment of the US Air Force to carry out 19 launches each on the Delta IV and 9 on the Atlas V. Lockheed Martin thus received orders with a total volume of 1.15 billion US dollars, plus subsidies from NASA, which contributed about half of the initial development costs of 1.6 billion dollars. However, when it became known that Boeing had operated industrial espionage in order to gain access to confidential data on the Atlas V, the Air Force withdrew seven flights from Delta IV and assigned them to the Atlas, which significantly improved the financial situation of the project. The maiden flight of the rocket in the Atlas V (401) version took place on August 21, 2002. The television satellite Hot Bird 6 from the European company Eutelsat was transported .

Startup costs

Since commercial customers do not publish the modalities of their start-up contracts, an exact determination of their start-up costs is not possible. However, US government agencies must disclose the cost of their startup jobs. Depending on the mission, costs for insurance and other services may be included in addition to the actual start, so that the figures may not be comparable with each other. Here are some details for NASA spacecraft launches:

version payload costs year
Atlas V (401) MRO 0$ 90 million 2005
Atlas V (401) LCROSS & LRO $ 136 million 2008
Atlas V (401) InSight ~ $ 160 million 2018
Atlas V (411) OSIRIS-REx ~ $ 183.5 million 2016
Atlas V (541) MSL $ 195 million 2011
Atlas V (551) New Horizons $ 188 million 2006

Manned missions with the Atlas V

As the end of the space shuttle's service life approached, the first studies on the suitability of the Atlas V for manned missions were carried out. In 2007 a letter of intent was signed with SpaceDev to check the launch of the manned space glider Dream Chaser . Extensive aerodynamic investigations with the orbiter on the naked body were carried out until 2014 as part of NASA's CCDev program. After that, the Dream Chaser was further developed as an unmanned supply ship and finally transferred from the Atlas V to the successor rocket Vulcan .

Due to the proven high start-up reliability, Lockheed Martin estimated the development time of a man rated version to be three years in 2008 . However, these plans were initially not implemented, as the Ares I with the Orion spaceship should serve as a replacement for the space shuttle. When the associated Constellation program was discontinued in 2010, there was again increased interest in an Atlas V version for manned space travel. On July 12, 2011, the rocket was officially included in NASA's Commercial Crew Development program, under which commercial, privately operated launch systems for the transport of people to the International Space Station are being developed. In August of the same year, Boeing announced that it would launch its manned CST-100 capsule, which is currently under development, with the Atlas V. For this purpose, ULA developed the rocket variant N22 without a payload fairing. The first launch of this rocket with a CTS-100 finally took place on December 20, 2019 as part of the unmanned test flight Boe-OFT . A first manned take-off is planned for 2021 with the Boe-CFT flight .

Missile variants not realized

In 2010, ULA announced a particularly powerful version of the Atlas V, known as the Atlas V Heavy Lift Vehicle ( Atlas V HLV for short , or sometimes Atlas V Heavy ). The plan was to develop and build this rocket only when a customer would book it for launch. As with the Delta IV Heavy, for this heavy-duty version , two additional liquid fuel boosters should be attached to the side of the central main stage , which would have corresponded in size and structure to the main stage. This measure should increase the maximum payload compared to the strongest variant already built, the Atlas V (551), by around 50%: for low earth orbit (LEO) from 18,814 kg to 29,400 kg and for a geosynchronous orbit from 8900 kg 13,000 kg (see below for details ). However, no customer was found for this rocket.

An Atlas V version with a payload capacity below the Atlas V (401), which instead of the Centaur upper stage should use an Agena 2000 upper stage (probably derived from the Agena ), was also deleted. Their transport capacity would have been 3,890 kg for a low- earth orbit or 1,842 kg for a geostationary transfer orbit .


Designation scheme

A key feature of the Atlas V is its modularity. Therefore, a systematic naming scheme was introduced for the individual variants, from which the parameters of the rocket can be read:

Atlas V naming german.svg

Note: The diameter of the payload fairing is not exactly 4 or 5 meters, but 4.2 and 5.4 meters. For the sake of simplicity, however, the decimal places are not included in the name of the rocket. With the 4.2 m cladding, the number of boosters is limited to 0 to 3. There is also the special variant N22 without payload fairing, with which the spacecraft CST-100 Starliner is transported. Of the 25 theoretically possible combinations, only ten have been used to date .

The same naming scheme is also used for the successor Vulcan .

Main level

The main stage viewed from below. The two nozzles of the RD-180 engine and the supply line for the liquid oxygen are clearly visible on the left.

The main stage of the Atlas V, also known as the Common Core Booster (CCB) , does most of the work during takeoff; it is the central part and the first stage of the rocket. It is 32.46 m high, has a diameter of 3.81 m and weighs 286 tonnes when fueled (21 tonnes empty). Its structure consists mainly of aluminum, with the oxidizer and fuel tank being stable and self-supporting, unlike previous launchers in the Atlas series, even without internal pressure (previous Atlas missiles would have collapsed without pressure in the tanks when they were raised). Although this construction is heavier, it simplifies handling when preparing for take-off and enables numerous heavy boosters to be attached. The inexpensive RP-1 mixture is used as fuel, which is burned with liquid oxygen as an oxidizer.

A liquid rocket engine of the type RD-180 is used as the engine, a modified version of the RD-170 , which is so reliable that it is also approved for manned space travel. It weighs 5480 kg, generates up to 4152  kN of thrust and achieves a specific impulse of 3316 m / s in a vacuum . The combustion works according to the staged combustion principle: the oxidizer liquid oxygen first flows past the two main combustion chambers and their nozzles to cool them, and is then burned with part of the RP-1 fuel in a small pre-combustion chamber. This creates a large amount of gas that is used to run a turbine , which in turn drives the fuel and oxidizer pumps. However, the gas is still very rich in unburned oxidizer, as only a small amount of the fuel was injected during the pre-combustion. Therefore, it is finally fed into the two main combustion chambers, where it is efficiently burned with the remaining fuel and expelled through the respective nozzles at high pressure. The advantages of this rather complex process are the compact design and the very high thrust potential. Ignition takes place by means of a hypergolic mixture, which ignites on contact, supplies the gas required to operate the pumps and thus sets the combustion cycle in motion. This concept is characterized by its simplicity and reliability; However, the engine can only be ignited once, which is not a disadvantage in the first rocket stage.

The RD-180 is produced by the Russian space company NPO Energomasch , which among other things also provides engines for the Soyuz and Proton launch vehicles. In order to be able to offer the engine in the USA, a joint venture was entered into with Rocketdyne , part of Pratt & Whitney since 2005 . The RD-180 is therefore officially distributed by the company RD AMROSS , which was created in this way.

The flight control takes place by means of the computer systems of the upper level ; the main stage only has facilities for communication, position determination and control of the movable nozzles of the RD-180 engine.


A booster for a test
Approximate location of the boosters

To increase the payload, there is the option of adding up to five solid fuel boosters produced by Aerojet . Each of these boosters has a diameter of 1.58 m, is 20 m long and weighs 47 tons. The shell is made of light and very resilient carbon fiber reinforced plastic , whereby these solid matter boosters are the largest components of their kind made from this material. The fuel used is APCP , a mixture of ammonium perchlorate and aluminum, embedded in HTPB , which develops a thrust of 1690 kN at takeoff and reaches a specific impulse of 2696 m / s (vacuum). To control the flight path, the nozzles can be swiveled by up to 3 °.

Since the solid fuel boosters can no longer be switched off once they have been ignited, they are only activated after the RD-180 engine of the main stage has been tested. If this has not reached its proper operating parameters within 2.7 seconds, the start is aborted. Otherwise, the ignition of the solid fuel booster marks the point of no return of the mission, since from this point on the rocket can only be stopped by detonating it. After about 100 seconds the fuel is used up and the boosters are thrown off, so that the main stage has to cope with the rest of the flight on its own.

A special feature of the Atlas V is that the solid fuel boosters are arranged asymmetrically - in contrast to other systems such as B. the Delta II. Also new is the possibility of using just a single booster if necessary. In order to compensate for the resulting unfavorable torques, the booster nozzles are mounted slightly outwards. Its thrust vector runs close to the rocket's center of gravity, but also no longer exactly perpendicular, which is why the rocket drifts slightly to the side when it takes off. In addition, the thrust vector control of the RD-180 engine is used to compensate .

Upper school

A Centaur upper level (SEC variant)

Two versions of the tried and tested Centaur upper stage are available for the Atlas V : One with two engines (Dual Engine Centaur, DEC), which is particularly suitable for heavy loads for launching into Low Earth Orbit (LEO), and one with only one engine (Single Engine Centaur, SEC), which is optimized for GTO satellites. The upper stage is in any case 12.68 m long, measures 3.05 m in diameter and weighs 23.077 or 23.292 tons, depending on the number of engines. These are of the type RL-10A-4-2 and weigh 175 kg each, generate up to 99 kN of thrust and achieve a specific impulse of 4422 m / s. They are designed, built and marketed by Pratt & Whitney.

In contrast to the main stage, the fuel used is not RP-1, but liquid hydrogen . Although this is difficult to store due to its very low boiling point (approx. 20  K ) and expensive to produce, the combustion is much more efficient than with RP-1. Liquid oxygen is also used as an oxidizer. The Centaur's tanks, unlike those of the main stage, are not self-supporting, so they have to be pressurized in order not to collapse. They are not made of aluminum, but of stainless steel and are insulated with 1.6 cm PVC foam due to the very cold liquid hydrogen .

The combustion takes place according to the principle of the expander cycle process. As in the main stage, the fuel (liquid hydrogen) first flows past the combustion chamber and the nozzle to cool them. As a result of the effect of heat, the liquid hydrogen evaporates suddenly and generates a pressure that is sufficient to drive the turbine of the fuel and oxidizer pump directly without further pre-combustion. After the hydrogen gas has passed the turbine, it is fed directly into the combustion chamber, where it is mixed with the oxidizer (liquid oxygen) and finally burned. Compared to the staged combustion process of the RD-180, this system does not achieve high thrust levels, but is less complex and much more efficient. The ignition takes place with the help of a spark generator , so the engine can be started several times.

The position control of the upper stage is carried out by means of the nozzles of the RL-10 engines, which can be swiveled out up to 51 cm, and twelve other small thrusters. These are operated with hydrazine , four nozzles have a thrust of 27 N, the remaining eight reach 40 N. The nozzles of the RL-10 engines are swiveled electro-mechanically in the single - engine version and hydraulically in the twin-engine version .

Payload fairing and adapter

LRO and LCROSS in a payload fairing of the 400 series
The MSL within a payload fairing of the 500 series

Two different payload fairing systems are available for the Atlas V, which also affect the connection with the upper level: the small 400 series and the large 500 series.

400 series

A payload fairing made of aluminum is available for payloads with a relatively small diameter. This can be extended with one or two sections below the relatively long conical tip rounded at the top. Its inner diameter is 3.75 m in the cylindrical part and 3.7084 m in the extensions. It has an outer diameter of 4.2 m, is 12 to 13.8 m long and weighs 2127 to 2487 kg (details see below ). The fairing houses a payload adapter and sits directly on the Centaur upper stage. This therefore has two adapters of its own that connect it to the main stage. One is made entirely of aluminum, is 0.65 m high and weighs 182 kg, the other reaches a height of 4.13 m, weighs 947 to 962 kg (depending on the number of engines in the upper stage) and has a CFRP surface that is supported by an aluminum structure. These payload fairings are derived from those of the Atlas III .

500 series

In order to be able to transport payloads with large volumes, the payload fairing of the 500 series was developed, which is characterized primarily by its larger diameter (5.4 m outside and max. 4.572 m inside) and its lighter sandwich construction (CFRP with aluminum honeycomb core) . This series also includes three versions of different sizes, which have a length of 20.7 to 26.5 m and a weight of 3542 to 4379 kg (see below for details ). In contrast to the 400 series, however, the payload fairing is not on the upper stage. This is located entirely within the casing, which is why both components are mounted on a common adapter system that connects them to the main stage. The first adapter, which is counted towards the fairing in terms of its dimensions and weight, has the shape of a downward tapering cylinder, accommodates the RL-10 engine of the upper stage and reduces the diameter from 5.4 m to 3.83 m. The next adapter is 3.81 m high, weighs 2212 to 2227 kg, depending on the number of engines of the upper stage, and is also constructed in honeycomb design. The last small adapter finally connects to the main stage. It is only 0.32 m high, weighs 285 kg and is made of aluminum. This payload fairing has a tip with an ogive shape so that the space for the payload becomes narrower in the upper area. This payload fairing, manufactured in Switzerland by RUAG and derived from the Ariane 5 , is the only non-US component of the Atlas V alongside the engines.

Multi-start adapter

For missions that do not exhaust the load capacity or the available volume of the Atlas V, a 61 cm high adapter can also be used, to which up to six additional small satellites can be attached. The construction known as the " EELV Secondary Payload Adapter " (ESPA) is made of aluminum, weighs 130 kg and is inserted between the primary payload and the Centaur upper stage. The satellites carried may not exceed a weight of approximately 181 kg and may measure a maximum of 76.2 cm in each dimension. The production costs for the ESPA are around 125,000  US dollars , a launch site for a small satellite costs around 1 to 2 million dollars, depending on its size.

The ESPA specification has become the de facto standard that is used for numerous missions with various types of missiles. With the ESPAStar, for example, a satellite platform is available on which the six payloads can either be suspended or used for experiments.

Double start capability

After some preliminary development work, in 2013 the United Launch Alliance commissioned the manufacturer of the Atlas payload fairing - the Swiss RUAG group - to develop a double launch device . The system called "Dual Spacecraft System" should be available from 2017, but has not yet been used (as of December 2020).


An Atlas V (551) in the VIF

Two launch sites are available for the Atlas V: The first is Launch Complex 3 at Vandenberg Air Force Base in California for inclinations from 63.4 °. Polar and slightly retrograde orbits such as the sun-synchronous orbit are also possible. The second is Launch Complex 41 at Cape Canaveral Air Force Station in Florida . From there, inclinations from 28.5 ° to 55 ° are possible.

In Vandenberg, the rocket is first assembled on the launch platform using the conventional method, while the “Clean Pad” concept is used in Cape Canaveral. Here, the rocket is already completely assembled in a 89 m high building called the Vertical Integration Facility (VIF) and located half a kilometer from the launch site. Then it is driven on the starting table to the starting place, whereby the starting tower integrated on the table is very simply constructed and only provides a power and data connection as well as tank systems. After a few automated tests and refueling, the Atlas V is ready to take off after a few hours.

This clean pad system has numerous advantages in terms of start preparation and risk management. Installation in a building protects the rocket from harmful environmental influences and makes it easier for workers to access the various components. Since the launch site can be made much simpler, the financial loss and the time required to rebuild after a possible explosion of the rocket on the launch pad are much lower than with conventional, often highly complex launch systems. In addition, thanks to the more effective operating procedure, rockets can be launched far more often, up to 15 units per year. These advantages contrast with the fact that additional buildings are required for the assembly and storage of the components. First of all, the old launch tower for the Titan III had to be blown up and the associated buildings converted into storage rooms for Atlas V components for the booster assembly. In addition, the Vertical Integration Facility had to be rebuilt. Overall, the renovation and new construction work took over three years.

Technical specifications

Versions and payload

List updated: January 3, 2021

An explanation of the designation scheme can be found above . The number of launches is tracked on the list of Atlas V rocket launches .

version booster Upper school ⌀ payload
max.payload (kg) status
Atlas V (401) 0 SEC 4.2 m 9,797 7,724 4,750 - in action
Atlas V (411) 1 SEC 4.2 m 1.2150 8,905 5,950 - in action
Atlas V (421) 2 SEC 4.2 m 14,067 10,290 6,890 - in action
Atlas V (431) 3 SEC 4.2 m 15,718 11,704 7,700 - in action
Atlas V (501) 0 SEC 5.4 m 8,123 6,424 3,775 - in action
Atlas V (511) 1 SEC 5.4 m 10,986 8,719 5,250 - Use planned
Atlas V (521) 2 SEC 5.4 m 13,490 10,758 6,475 2,632 in action
Atlas V (531) 3 SEC 5.4 m 15,575 12,473 7,475 3,192 in action
Atlas V (541) 4th SEC 5.4 m 17,443 14,019 8,290 3,630 in action
Atlas V (551) 5 SEC 5.4 m 18,814 15,179 8,900 3,904 in action
Atlas V (N22) 2 SEC none not comparable
public light
- - - in action
Atlas V HLV 2 ( CCBs ) DEC 5.4 m 29,400 - 13,000 6,454 discarded

Parameters for the specified data:

Low Earth Orbit (LEO)

Sun synchronous orbit (SSO)

  • Starting point: VAFB
  • Perigee / apogee: 200 km (circular path)

Geosynchronous Orbit (GSO)

  • Launch site: CCAFS
  • Inclination: 0 °

Geostationary Transfer Orbit (GTO)

  • Launch site: CCAFS
  • ΔV to GSO: 1804 m / s
  • Inclination: 27.0 °
  • Perigee: at least 185 km
  • Apogee: 35,786 km

Used payload fairing

  • 400 series: Medium length (12.9 m)
  • 500 series: short length (20.7 m)
  • HLV: Great length (26.5 m)

Weights and dimensions

All data according to United Launch Alliance: Atlas V Launch Services - User's Guide (2010) , unless otherwise stated.

component Main level booster Upper school
400 series payload fairing

500 series payload fairing
Empty weight ( t ) 21,351 5.735 2.247 (SEC)
2.462 (DEC)
2.127 (short)
2.305 (medium)
2.487 (long)
3.524 (short)
4.003 (medium)
4.379 (long)
Fuel capacity ( t ) 284,089 40.962 20,830 - -
Length ( m ) 32.46 20th 12.68 12.0 (short)
12.9 (medium)
13.8 (long)
20.7 (short)
23.4 (medium)
26.5 (long)
Diameter ( m ) 3.81 1.58 3.05 4.2 5.4


The RD-180 engine during a test run

All data from Lockheed Martin: Atlas V Propulsion - Powered by Innovation (2006) , unless otherwise stated.

component RD-180 RL-10A-4-2 booster
Drive mix RP-1 + LOX LH 2 + LOX NH 4 ClO 4 + Al ,
embedded in HTPB
Weight ( kg ) 5480 175 k. A.
Length ( m ) 3.56 2.32 k. A.
Diameter ( m ) 3.15 1.17 1.57
Thrust on the ground ( kN ) 3826 - 1690
Thrust in vacuum ( kN ) 4152 99 -
Specific impulse
on the ground (m / s)
3053 - -
Specific impulse
in a vacuum (m / s)
3312 4422 2696
Combustion chamber pressure ( bar ) 256.62 42.01 k. A.

Start list


Web links

Commons : Atlas V  - album with pictures, videos and audio files


  1. At start no. 10 on June 15, 2007 there was an error in the Centaur upper level. As a result, the transported satellite was placed in an orbit that was too low. Since he was able to reach the target orbit on his own, the start is at least a partial success. The ULA regards the mission as a complete success.
  2. This has been practiced by ESA with Ariane 5 since 1996 . The space shuttle was brought to the LC-39 launch site, but the launch tower was very complex, as the missions carried out were always manned and therefore many additional facilities such as B. Elevators required. Except for the particularly large and heavy ones, the payloads were only accommodated there in the payload compartment of the space shuttle.

Individual evidence

  1. ^ Sandra Erwin: Air Force awards launch vehicle development contracts to Blue Origin, Northrop Grumman, ULA . Spacenews, October 10, 2018.
  2. a b c d e f g h i j Atlas V (on Retrieved August 13, 2012 .
  3. a b c Factsheets: Evolved Expendable Launch Vehicle. (No longer available online.) Archived from the original on April 27, 2014 ; Retrieved October 22, 2011 .
  4. a b c d e f g h i j Bernd Leitenberger: The Atlas V. Accessed on October 13, 2011 .
  5. ^ NASA Awards Launch Services Contract for InSight Mission. Retrieved January 11, 2014 .
  6. InSight Launch Press Kit. Retrieved June 12, 2018 .
  7. NASA Selects Launch Services Contract for OSIRIS-REx Mission. Retrieved January 11, 2014 .
  8. Chris Bergin and Braddock Gaskill: SpaceDev announce Dream Chaser agreement with ULA Atlas V., April 10, 2007, accessed December 31, 2018 .
  9. Chris Bergin: Dream Chaser passes Wind Tunnel tests for CCiCap Milestone., May 19, 2014, accessed December 31, 2018 .
  10. No major hurdles to upgrade Atlas V rockets for people. Retrieved October 17, 2011 .
  11. NASA agrees to help modify Atlas 5 rocket for astronauts. Retrieved October 17, 2011 .
  12. Boeing Chooses Atlas V to Shoot CST-100 Capsule into Orbit. (No longer available online.) Archived from the original on September 9, 2011 ; Retrieved October 17, 2011 .
  13. ^ Atlas V Launch Services - User's Guide. (PDF; 27 MB) March 2010 Revision 11. United Launch Alliance, March 2010, pp. 1–3 , accessed on December 31, 2018 (English): “The Atlas V Heavy Lift Vehicle has been developed up to a Critical Design Review (CDR) level of completeness. The completion of the design is currently on hold pending firm mission requirements for this level of performance capability. At the time of this publication, the Atlas V HLV is approximately 30 months from authority to proceed (ATP) to launch, but would require a 36-month integration cycle [...] "
  14. a b c d e f g h i j k l m n o p q r s t u Atlas V Launch Services - User's Guide. (PDF; 27 MB) March 2010 Revision 11. United Launch Alliance, March 2010, accessed on December 31, 2018 (English).
  15. Gunter's Space Page: Atlas 5 (Atlas V)
  16. a b c d e f g Atlas V Propulsion - Powered by Innovation. (PDF) Lockheed Martin, 2006, archived from the original on December 17, 2011 ; accessed on October 14, 2011 (English).
  17. ^ Atlas V 400 Series. (No longer available online.) Archived from the original on June 20, 2008 ; Retrieved October 13, 2011 .
  18. US Centaur upper stage. Retrieved October 14, 2011 .
  19. Bernd Leitenberger: Atlas III Accessed: December 4, 2011
  20. a b Secondary Payload Planner's Guide For Use On The EELV Secondary Payload Adapter. (PDF; 1.3 MB) DoD Space Test Program, November 1, 2004, accessed on June 12, 2018 .
  21. ESPA Overview. MOOG CSA Engineering, accessed June 12, 2018 .
  22. ESPAStar factsheet. (PDF; 1.5 MB) Northrop Grumman, May 29, 2018, accessed on June 12, 2018 .
  23. Thomas Weyrauch: ULA: Double starts with components from RUAG in, June 28, 2013, accessed on June 30, 2013.
  24. ^ Roy Miller: Dual Spacecraft System. (PDF) United Launch Alliance, 2011, accessed on April 14, 2019 .
This article was added to the list of articles worth reading on February 28, 2012 in this version .