Vulcan Centaur is a

two-stage-to-orbit A two-stage-to-orbit (TSTO) or two-stage rocket launch vehicle is a spacecraft in which two distinct stages provide propulsion consecutively in order to achieve orbital velocity. It is intermediate between a three-stage-to-orbit launcher and a hy ...

heavy-lift launch vehicle A heavy-lift launch vehicle, HLV or HLLV, is an orbital launch vehicle capable of lifting between (by NASA classification) or between (by Russian classification) into low Earth orbit (LEO).50t payloads" , operational heavy-lift launch vehicl ...

that is under development by the

United Launch Alliance United Launch Alliance (ULA), legally United Launch Alliance, LLC, is an American spacecraft launch service provider that manufactures and operates a number of rocket vehicles that are capable of launching spacecraft into orbits around Earth, ...

(ULA) since 2014 with an initial flight expected in early 2023. It is principally designed to meet launch demands for the U.S. government's

National Security Space Launch National Security Space Launch (NSSL) — formerly Evolved Expendable Launch Vehicle (EELV) from 1994 to 2019 — is a program of the United States Space Force (USSF) intended to assure access to space for United States Department of Defense and o ...

(NSSL) program for use by the

United States Space Force The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world's only independent space force. Along with its sister branch, the U.S. Air Force, the Space ...

and U.S. intelligence agencies for national security satellite launches. The maiden flight is slated to launch Astrobotic Technology's ''Peregrine'' lunar lander for NASA's

Commercial Lunar Payload Services Commercial Lunar Payload Services (CLPS) is a NASA program to contract transportation services able to send small robotic landers and rovers to the Moon's south polar region mostly with the goals of scouting for lunar resources, testing in sit ...

(CLPS) program and

Kuiper Systems Kuiper Systems LLC is a subsidiary of Amazon that was set up in 2019 to deploy a large broadband satellite internet constellation to provide broadband internet connectivity. The deployment is also referred to by its project name "Project Kuipe ...

' Kuipersat-1 and Kuipersat-2, no earlier than 2023, after multiple delays from the initially planned first flight in 2019.

Description

Vulcan is ULA's first new launch vehicle design; it adapts and evolves technologies that were developed for the

Atlas V Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was originally designed by Lockheed Martin, now being operated by United Launch Alliance (ULA), a joint venture between Lockheed Mart ...

and

Delta IV Delta IV is a group of five expendable launch systems in the Delta rocket family introduced in the early 2000s. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) program, t ...

rockets of the USAF's EELV program. The first-stage propellant tanks have the same diameter as the Delta IV Common Booster Core but will contain

liquid methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ear ...

and

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an app ...

propellants A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the e ...

rather than the Delta IV's

liquid hydrogen Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully l ...

and liquid oxygen. Vulcan's

upper stage A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is ...

is the Centaur V, an upgraded variant of the Centaur III, the world’s first high energy upper stage. The Centaur III variant is currently used on the Atlas V. A version of the RL-10 engine with a

nozzle extension A nozzle extension is an extension of the nozzle of a reaction/rocket engine. The application of nozzle extensions improves the efficiency of rocket engines in vacuum by increasing the nozzle expansion ratio. As a rule, their modern design assu ...

, the RL-10CX, will be used on the Vulcan Centaur Heavy. Previous plans called for the Centaur V to be eventually upgraded with

Integrated Vehicle Fluids The Advanced Cryogenic Evolved Stage (ACES) was a proposed liquid oxygen/liquid hydrogen upper-stage from 2005 to 2020 for use on a number of different launch vehicles produced by Boeing, Lockheed Martin, and after a late-2006 merger, United Lau ...

technology to become the

Advanced Cryogenic Evolved Stage The Advanced Cryogenic Evolved Stage (ACES) was a proposed liquid oxygen/liquid hydrogen upper-stage from 2005 to 2020 for use on a number of different launch vehicles produced by Boeing, Lockheed Martin, and after a late-2006 merger, United La ...

(ACES), but this was subsequently cancelled. Vulcan is intended to undergo the human-rating certification process to allow the launch of crewed craft, such as the

Boeing CST-100 Starliner The Boeing CST-100 Starliner
is a class of two partially

or a future version of the

Sierra Nevada Dream Chaser Dream Chaser is an American reusable lifting-body spaceplane being developed by Sierra Nevada Corporation (SNC) Space Systems. Originally intended as a crewed vehicle, the Dream Chaser Space System is set to be produced after the cargo varia ...

spaceplane A spaceplane is a vehicle that can fly and glide like an aircraft in Earth's atmosphere and maneuver like a spacecraft in outer space. To do so, spaceplanes must incorporate features of both aircraft and spacecraft. Orbital spaceplanes te ...

. The Vulcan booster has a outer diameter to support the Blue Origin BE-4 engines'

fuel. In September 2018, after a competition with the

Aerojet Rocketdyne Aerojet Rocketdyne is an American manufacturer of rocket, hypersonic, and electric propulsive systems for space, defense, civil and commercial applications. Headquartered in Sacramento, California, the company is owned by Aerojet Rocketdyne Hold ...

AR1 The Aerojet Rocketdyne AR1 is a thrust RP-1/LOX oxidizer-rich staged combustion cycle rocket engine project. The engine was conceived in 2014, and received US government funding to build a prototype engine in 2016. By 2018, the USAF had com ...

, the BE-4 was selected to power Vulcan's first stage. Up to six GEM-63XL solid rocket boosters (SRB)s can be attached to the first stage in pairs, providing additional thrust during the first part of the flight and allowing the six-SRB Vulcan Centaur Heavy to launch a higher mass payload than the most capable Atlas V 551.

Versions

The Vulcan Centaur will have a four-character designation for each configuration, in which the first character represents the first stage of the vehicle; Vulcan is designated with the letter "V". The second character shows the upper stage; Centaur is designated "C". The third character represents the number of SRBs attached to the Vulcan; "0", "2", "4" or "6". The final character represents the payload-fairing length configuration, which is indicated by "S" (Standard; ) or "L" (Long; ). For example, "VC6L" would represent a Vulcan first stage, a Centaur upper stage, six SRBs and a long-configuration fairing. The single-core Vulcan Centaur Heavy will have a Vulcan first stage, a Centaur upper stage with RL10CX engines with a nozzle extension and six SRBs.

Capabilities

As of November 2019, the Vulcan Centaur payload figures are as follows: Payload to low-Earth orbit (LEO) is for a 200km (120mi) circular orbit at a 28.7° inclination; payload to the International Space Station is for a 407km (253mi) circular orbit at 51.6° inclination; payload to polar LEO is for a 200km (120mi) circular orbit at 90° inclination. These capabilities are driven by the need to meet NSSL requirements, with room for future growth. A single-core Vulcan Centaur with six solid-rocket boosters can put 27,200 kilograms into low-Earth orbit. This is almost as much as the three-core Delta IV Heavy.

History

Background

ULA had considered a number of launch vehicle concepts in the decade since the company was formed in 2006. Various concepts for derivative vehicles based on the

Atlas An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geograp ...

and

Delta Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D ( NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also ...

lines of launch vehicles they inherited from their predecessor companies were presented to the US government for funding. None were funded beyond the concept stage. In early 2014, geopolitical and US

political Politics (from , ) is the set of activities that are associated with making decisions in groups, or other forms of power relations among individuals, such as the distribution of resources or status. The branch of social science that stud ...

considerations led to an effort by ULA to consider the possible replacement of the Russian-supplied

RD-180 The RD-180 ( rus, РД-180, Ракетный Двигатель-180, Raketnyy Dvigatel-180) is a rocket engine designed and built in Russia. It features a dual combustion chamber, dual- nozzle design and is fueled by a RP-1/ LOX mixture. The RD ...

engine used on the first stage booster of the Atlas V. Events such as the Annexation of Crimea by the Russian Federation in February 2014 brought into focus that relying on foreign hardware to launch critical national security spacecraft could be undesirable. Formal study contracts were issued by ULA in June 2014 to a number of US rocket engine suppliers. ULA was also facing competition from SpaceX—then seen to affect its core national security market of US military launches—and by July 2014, the

US Congress The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washin ...

was debating whether to legislatively ban future use of the RD-180 engine. In September 2014, ULA announced that it had entered into a partnership with Blue Origin to develop the BE-4 liquid oxygen (

LOX Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an appli ...

) and

(CH₄) engine to replace the RD-180 on a new first stage booster. The engine was already in its third year of development by Blue Origin, and ULA said it expected the new stage and engine to start flying no earlier than 2019. Two of the -thrust BE-4 engines were to be used on a new launch vehicle booster. In October 2014, ULA announced a major restructuring of company processes and workforce in order to halve launch costs. One of the reasons given for the restructuring and new cost reduction goals was new competition in the launch market from SpaceX. ULA stated it planned to have preliminary design ideas in place for a blending of its existing

and

technologies by the end of 2014, in order to build a successor to the Atlas V that would allow them to cut Atlas V launch costs in half.

Announcement

At the time of the 2015 announcement, ULA proposed an incremental approach to rolling out the new launch vehicle and its technologies. Vulcan deployment was expected to begin with a new first stage that was based on the Delta IV's fuselage diameter and production process, and initially expected to use two BE-4 engines or the

as an alternative. The initial second stage was planned to be the Atlas V's Common Centaur and Centaur III with its existing

RL10 The RL10 is a liquid-fuel cryogenic rocket engine built in the United States by Aerojet Rocketdyne that burns cryogenic liquid hydrogen and liquid oxygen propellants. Modern versions produce up to of thrust per engine in vacuum. Three RL10 ve ...

engine. A later upgrade, the

(ACES), was conceptually planned for full development in the late 2010s and to be introduced a few years after Vulcan's first flight. ULA also announced a design concept for reuse of the Vulcan booster engines, thrust structure and first stage avionics, which could be detached as a module from the propellant tanks after booster engine cutoff; the module would re-enter the atmosphere behind an inflatable heat shield. Neither the ACES second stage nor the SMART reuse for the first stage became funded development projects by ULA , even though ULA stated the "first stage propulsion module accounts for around 65% of Vulcan Centaur's costs."

Funding

Through the first several years, the ULA board of directors made quarterly funding commitments to Vulcan Centaur development. , the U.S. government had committed approximately US$1.2 billion in a

public–private partnership A public–private partnership (PPP, 3P, or P3) is a long-term arrangement between a government and private sector institutions.Hodge, G. A and Greve, C. (2007), Public–Private Partnerships: An International Performance Review, Public Adminis ...

to Vulcan Centaur development and future funding was dependent on ULA securing an NSSL contract. By March 2016, the

United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...

(USAF) had committed up to US$202 million of funding for Vulcan development. ULA had not yet estimated the total cost of development but CEO

Tory Bruno Tory Bruno (born November 3, 1961 as Salvatore Thomas Bruno) is an American aerospace engineer and executive. He has been the CEO of United Launch Alliance (ULA) since August 2014. Before ULA, he worked at Lockheed Martin, where he made the trans ...

noted "new rockets typically cost US$2 billion, including US$1 billion for the main engine". In April 2016, ULA Board of Directors member and President of

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and p ...

's Network and Space Systems (N&SS) division Craig Cooning expressed confidence in the possibility of further USAF funding of Vulcan development. In March 2018, Tory Bruno said the Vulcan-Centaur had been "75% privately funded" up to that point. In October 2018, following a request for proposals and technical evaluation, ULA was awarded US$967 million to develop a prototype Vulcan launch system as part of the

program. Other providers Blue Origin and Northrop Grumman Innovation Systems were awarded US$500 million and US$792 million in development funding, with detailed proposals and a competitive selection process to follow in 2019. The USAF's goal with the next generation of Launch Service Agreements was to desist from "buying rockets" and move to acquire services from

launch service provider A launch service provider (LSP) is a type of company which specialises in launching spacecraft. In 2018, the launch services sector accounted for $5.5 billion out of a total $344.5 billion "global space economy". It is responsible for the ordering ...

s but U.S. government funding of launch vehicle development continued. A rough mock-up of the Vulcan Centaur

Into production

In September 2015, it was announced BE-4 rocket engine production would be expanded to increase production capacity for testing. The following January, ULA was designing two versions of the Vulcan first stage; the BE-4 version has a diameter to support the use of less-dense methane fuel. In late 2017, the upper stage was changed to the larger and heavier Centaur V, and the launch vehicle was renamed Vulcan Centaur. The single-core Vulcan Centaur will be capable of lifting "30% more" than a Delta IV Heavy, meeting the NSSL requirements. In May 2018, ULA announced the selection of

's RL10 engine for the Vulcan Centaur upper stage. That September 2018, ULA announced the selection of the Blue Origin BE-4 engine for Vulcan's booster. That October 2018, the USAF released an NSSL launch service agreement with new requirements, delaying Vulcan's initial launch to April 2021, after an earlier postponement to 2020. On 8 July 2019, CEO Tory Bruno released images of two Vulcan qualification test articles — the liquefied natural gas tank and thrust structure — on

Twitter Twitter is an online social media and social networking service owned and operated by American company Twitter, Inc., on which users post and interact with 280-character-long messages known as "tweets". Registered users can post, like, and ...

. The following day, Peter Guggenbach, the CEO of RUAG Space, released an image of a Vulcan payload attachment fitting. On 31 July the same year, two images of the mated LNG tank and thrust structure were similarly released. On 2 August 2019, Blue Origin released on Twitter an image of a BE-4 engine at full power on a test stand. On 6 August 2019, the first two parts of Vulcan's

mobile launcher platform A mobile launcher platform (MLP), also known as mobile launch platform, is a structure used to support a large multistage space vehicle which is assembled (stacked) vertically in an integration facility (e.g. the Vehicle Assembly Building) and t ...

(MLP) were transported to the Spaceflight Processing Operations Center (SPOC) near

SLC-40 Space Launch Complex 40 (SLC-40), previously Launch Complex 40 (LC-40) is a launch pad for rockets located at the north end of Cape Canaveral Space Force Station, Florida. The launch pad was used by the United States Air Force for 55 Titan III ...

and SLC-41, Cape Canaveral,

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

. The MLP was fabricated in eight sections and will move at on existing rail dollies and stand tall. On 12 August 2019, ULA submitted Vulcan Centaur for phase 2 of the USAF's launch services competition. As of February 2020, the tankage for the second operational rocket was under construction in the ULA factory in

Decatur, Alabama Decatur (dɪˈkeɪtə(r)) is the largest city and county seat of Morgan County (with a portion also in Limestone County) in the U.S. state of Alabama. Nicknamed "The River City", it is located in northern Alabama on the banks of Wheeler La ...

. In October 2019, the first launch of Vulcan was planned for July 2021, carrying Astrobotic Technology's ''Peregrine'' lunar lander. In June 2020, ULA said it could be earlier and announced a target launch date of early 2021.Wall, Mike
"SpaceX Falcon 9 Rocket Will Launch Private Moon Lander in 2021"
SPACE.com 2 October 2019 Quote: "But Peregrine will fly on a different rocket, United Launch Alliance's Vulcan Centaur, which is still in development. The 2021 Peregrine mission will be the first for both the lander and its launch vehicle" On 7 August 2020, the

awarded ULA 60% of all

payloads from 2022 to 2027. That December 2020, ULA said BE-4 engine delivery was expected in mid-2021, and that the Vulcan's first launch would not happen before the end of 2021.Bezos' Blue Origin to deliver first flight-ready rocket engines next summer
Reuters, December 17, 2020, accessed 20 December 2020. In June 2021, Astrobotic reported that due to the

COVID-19 pandemic The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identi ...

, they needed more time to prepare ''Peregrine'', delaying the first flight of Vulcan to 2022 and later to 2023. The Government Accountability Office (GAO) also stated that the first-stage engine was experiencing technical difficulties, and may not be qualified in time to support a Vulcan launch in 2021.

Testing before first flight

In February 2021, ULA shipped the first completed Vulcan core booster to Florida for pathfinder tests ahead of the Vulcan's debut launch. The Pathfinder Tanking Test core booster was transferred to SLC-41 for first stage cryogenic tanking tests in April 2021.''Vulcan: Pathfinder fueling tests planned'' Aug 2021
/ref> It was loaded with just LOX in August 2021, and with just CH₄ in September 2021, and was rolled out to SLC-41 on Oct 4 for a combined LOX & CH₄ tanking and pressurisation test on Oct 5.

First flight hardware

Certification flights

On 14 August 2019, ULA won a commercial competition when it was announced the second Vulcan certification flight would be SNC Demo-1, the first of six Dream Chaser CRS-2 flights awarded to ULA. Launches are planned to begin in 2023. They will use the four-SRB Vulcan configuration. On 19 August 2019, it was announced Astrobotic Technology selected ULA to launch their Peregrine lander on the first Vulcan certification flight. Peregrine is scheduled to be launched in early 2023 from SLC-41 at

Cape Canaveral Space Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

(CCSFS) on a mission to the lunar surface. The Space Force's USSF-51 launch in late 2022 had been intended to be the first national security classified mission, but in May 2021 the spacecraft was reassigned to an

to "mitigate schedule risk associated with Vulcan Centaur non-recurring design validation".

NASA Launch Services Program

In early 2021, NASA added the Vulcan Centaur to the Launch Services II contract (NLS II). This makes the Vulcan Centaur part of the Launch Services Program and subjects it to the "on-ramp" provisions in NLS II. The on-ramp provisions allow existing launch providers to introduce new vehicles that NASA has not yet provided for.

Potential upgrades

Since the formal announcement in 2015, ULA has spoken of several technologies that would extend the Vulcan launch vehicle's capabilities. These include enhancements to the first stage to make the most expensive components potentially reusable and enhancements to the second stage to increase its long-term mission duration to operate for months in Earth orbit

cislunar space Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...

Long-endurance upper stages

The ACES upper stage—fueled with liquid oxygen (LOX) and liquid hydrogen (LH) and powered by up to four rocket engines with the engine type yet to be selected—was a conceptual upgrade to Vulcan's upper stage at the time of the announcement in 2015. This stage could subsequently be upgraded to include the Integrated Vehicle Fluids technology that would allow the upper stage a much longer in-orbit life of weeks rather than hours. The ACES upper stage was eventually cancelled when in September 2020, ULA made public that the ACES development would not be continued and the Vulcan second stage would now be the Centaur V upper stage. The Centaur V is based on the upper stage used by the Atlas V but larger and more powerful. A senior executive at ULA said the Centaur V design was also heavily influenced by ACES. However, ULA said in 2021 that it is working to add more value to upper stages by having them perform tasks such as operating as space tugs. CEO Tory Bruno says ULA is working on upper stages with hundreds of times the endurance of those currently in use.

SMART reuse

The Sensible Modular Autonomous Return Technology (SMART) reuse concept was also announced during the initial April 2015 unveiling of Vulcan. The booster engines, avionics, and thrust structure would be detached as a module from the propellant tanks after booster engine cutoff. The module would descend through the atmosphere behind an inflatable heat shield. After parachute deployment, a helicopter would capture the module in mid-air. ULA estimated this technology would reduce the cost of the first stage propulsion by 90%, and 65% of the total first-stage cost. By 2020, ULA had not announced firm plans to fund, build and test this engine-reuse concept, though in late 2019 they stated they were "still planning to eventually reuse Vulcan's first-stage engines". In April 2021 CEO Tory Bruno said that the additional launches purchased by Amazon for the Kuiper satellite constellation would require a higher launch cadence and that this provided support for the business case to go forward with the SMART concept. In July 2022, ULA pivoted and changed the high-level design objective of the engine reuse recovery concept. Rather than recover the descending booster engines with a helicopter, ULA is now planning to attempt recovery of the engines following atmospheric reentry, descent, and

splashdown Splashdown is the method of landing a spacecraft by parachute in a body of water. It was used by crewed American space capsules prior to the Space Shuttle program, by SpaceX Dragon and Dragon 2 capsules and by NASA's Orion Multipurpose Crew ...

floating in the ocean on the inflatable

aeroshell An aeroshell is a rigid heat-shielded shell that helps decelerate and protects a spacecraft vehicle from pressure, heat, and possible debris created by drag during atmospheric entry (see blunt body theory). Its main components consist of a heat ...

Three-core variant

As of late 2020, ULA said it is studying a possible three-core variant of the Vulcan Centaur. This rocket was tentatively dubbed the Vulcan Heavy, not to be confused with the planned single-core Vulcan Centaur Heavy with six SRBs.

Planned launches

References

External links

*
xTTkrxVR_20 ISPCS 2015 Keynote
Mark Peller, Program Manager of Major Development at ULA and Vulcan Program Manager discusses Vulcan, 8 October 2015, Key discussion of Vulcan is at 12:20 point in video.
A current ULA Vulcan with 5.4 m Centaur image
{{Reusable launch systems United Launch Alliance space launch vehicles