Vulcan Centaur is the primary launch vehicle of United Launch Alliance (ULA), the Boeing-Lockheed Martin joint venture that has launched US government payloads since 2006. First flown on January 8, 2024, the 61.6-meter rocket replaces both the Atlas V and Delta IV, carries up to 27,200 kg to low Earth orbit, and combines a methane-fueled first stage, powered by two BE-4 engines purchased from Blue Origin, with the Centaur V hydrogen upper stage.[1][7]
Status as of August 2026
Vulcan Centaur is grounded. The rocket has flown four times since its January 2024 debut and delivered every payload to its intended orbit, but two of those flights suffered nozzle failures on their strap-on solid boosters, and after the second, on the USSF-87 mission of February 12, 2026, the US Space Force paused Vulcan national security launches.[2][3] The pause was still in place in early August 2026, with more than 80 missions waiting in ULA's backlog.[12] Northrop Grumman static-fired a GEM 63XL booster with a redesigned nozzle on April 15, 2026, and ULA is retrofitting its BE-4 engines with a modified oxygen valve as it works to fly again before the end of the year.[6][13] The return-to-flight mission is expected to be Vulcan's first launch for Amazon's Leo constellation rather than a military flight,[13][14] targeted for September 2026;[18] ULA ran a wet dress rehearsal of that rocket at Cape Canaveral on August 6, 2026.[19] The Centaur V upper stage also remains slated to fly on NASA's Space Launch System, beginning with Artemis V under a March 2026 contract.[9][22]
Development
ULA announced Vulcan in 2015 under pressure from two directions: SpaceX was undercutting its prices, and Congress had ordered an end to the Russian RD-180 engine that powered Atlas V after the 2014 annexation of Crimea. ULA selected Blue Origin's BE-4, a staged-combustion engine burning liquefied natural gas, over an Aerojet Rocketdyne alternative in 2018, making Vulcan dependent on engines built by a company that also competes with it directly through New Glenn, which uses seven BE-4s per booster.[1]
First flight slipped from 2019 to 2024, delayed by BE-4 development, a Centaur V test stand anomaly in 2023, and payload readiness. Unusually for a new rocket, Vulcan is not reusable, though ULA has studied recovering the engine section by parachute under a concept called SMART reuse.[1]
Design and specifications
Vulcan flies in four main configurations, designated by the number of GEM 63XL solid rocket boosters (zero, two, four, or six) supplied by Northrop Grumman. The Centaur V upper stage, a 5.4-meter-diameter evolution of the long-serving Centaur, burns liquid hydrogen through two RL10C engines and is designed for long-duration missions that deliver payloads directly to geostationary or other high-energy orbits, a specialty of ULA's national security work.[1][7] A version of Centaur V is also slated to serve as the upper stage of NASA's Space Launch System beginning with Artemis V: NASA cancelled the delayed and over-budget Exploration Upper Stage in February 2026 and awarded ULA a sole-source contract for replacement stages in early March, initially aimed at Artemis IV before NASA shifted the last ICPS stage to that mission in May.[9][22]
| Parameter | Vulcan Centaur (VC6) |
|---|---|
| Height | 61.6 m |
| Diameter | 5.4 m |
| Liftoff mass | Up to 546,700 kg |
| First stage engines | 2 BE-4 (liquefied natural gas / liquid oxygen) |
| Solid boosters | Up to 6 GEM 63XL |
| Upper stage | Centaur V, 2 RL10C (hydrogen/oxygen) |
| Payload to low Earth orbit | 27,200 kg |
| Payload to geostationary transfer orbit | 14,500 kg |
| Payload fairing | 5.4 m diameter; 15.5 m or 21.3 m length |
| Launch sites | SLC-41 Cape Canaveral; SLC-3E Vandenberg (in conversion) |
Performance scales with the booster count. ULA quotes the following payload masses by configuration; an L suffix (as in VC4L or VC6L) denotes the 21.3-meter long fairing, an S the standard length.[7]
| Configuration | Solid boosters | Low Earth orbit | Geostationary transfer | Geostationary direct |
|---|---|---|---|---|
| VC0 | 0 | 10,800 kg | 3,500 kg | Not offered |
| VC2 | 2 | 19,000 kg | 8,400 kg | 2,600 kg |
| VC4 | 4 | 24,600 kg | 11,700 kg | 4,900 kg |
| VC6 | 6 | 27,200 kg | 14,500 kg | 6,500 kg |
All four flights to date have launched from Space Launch Complex 41 at Cape Canaveral. For West Coast missions ULA is converting SLC-3E at Vandenberg Space Force Base, the pad Atlas V used there, and delivered the first Vulcan booster to Vandenberg in February 2026 while construction continued.[20]
Launch history
| Flight | Date | Configuration | Payload | Outcome |
|---|---|---|---|---|
| Cert-1 | January 8, 2024 | VC2S | Astrobotic Peregrine lunar lander | Success |
| Cert-2 | October 4, 2024 | VC2S | Mass simulator | Success (booster nozzle anomaly) |
| USSF-106 | August 12, 2025 | VC4S | NTS-3 and national security payloads | Success |
| USSF-87 | February 12, 2026 | VC4S | GSSAP surveillance satellites | Success (booster nozzle anomaly) |
Vulcan's debut flight, Cert-1, lifted off from Cape Canaveral's Space Launch Complex 41 on January 8, 2024, sending Astrobotic's Peregrine lander toward the Moon; the rocket performed flawlessly, though the lander itself was doomed hours later by a propellant leak unrelated to the launch.[1][2] Cert-2, flown October 4, 2024 with an inert mass simulator after Sierra Space's Dream Chaser missed its slot, suffered the program's first anomaly: the nozzle of one GEM 63XL booster broke apart about 37 seconds into flight. The vehicle compensated and completed its trajectory, and ULA traced the failure to a manufacturing defect in an insulator bonded inside the nozzle, an investigation aided by recovering both spent boosters from the ocean for comparison.[11] The US Space Force certified Vulcan for national security launches in March 2025, closing out 52 certification criteria in a review that had started in 2016.[8]
National security role
The national security certification Vulcan earned in March 2025 carries most of the rocket's business case.[8] ULA holds the majority of missions in Phase 2 of the National Security Space Launch program, and in April 2025 the Space Force assigned it 19 of the first 54 missions in Phase 3 Lane 2, contracts worth about $5.4 billion, alongside 28 missions for SpaceX and 7 for Blue Origin.[10] Vulcan's first such flight, USSF-106, launched on August 12, 2025, placing the Navigation Technology Satellite-3 experimental payload and other Department of Defense spacecraft into orbit after a multi-burn Centaur V profile to geosynchronous altitude.[4]
USSF-87 followed on February 12, 2026, lofting two Geosynchronous Space Situational Awareness Program satellites. Less than 30 seconds after liftoff, observers saw debris and an exhaust plume consistent with a burn-through of a nozzle on one of the four solid boosters, the same failure mode as 2024. The SRBs jettisoned on time and the mission succeeded, but the Space Force paused further Vulcan national security flights, with officials warning the investigation could take many months.[3][5]
Northrop Grumman static-fired a GEM 63XL with nozzle design changes on April 15, 2026, a test ULA confirmed as successful in May while the root cause work continued.[6] Deliveries of the redesigned motors may not begin until near the end of 2026, and the Space Force pause was still in place in early August, leaving Vulcan with a single flight in 2026 and no announced date for its next national security launch.[12]
Dream Chaser and Amazon Leo
Two commercial customers dominate Vulcan's future manifest. Sierra Space's Dream Chaser Tenacity, a winged cargo spaceplane, is booked to fly on a Vulcan in the VC4L (long fairing) configuration. Its debut was originally a resupply mission to the International Space Station, but NASA restructured the cargo contract in September 2025; the flight, still targeted for late 2026, is now a free-flying demonstration that will not dock with the station.[15]
Amazon holds 38 Vulcan launches for its Leo broadband constellation (formerly Project Kuiper), the largest block of the largest commercial launch purchase ever made; Amazon expects about 40 satellites on each early Vulcan flight, carried on a six-booster VC6L.[1][2][21] ULA finished the Atlas V portion of the arrangement on July 2, 2026, when the last of eight Atlas V flights for Leo brought that rocket's contribution to 224 satellites and left ULA's six remaining Atlas Vs reserved for Boeing's Starliner capsule.[14]
The first Vulcan Leo mission, targeted for September 2026 subject to the anomaly investigation, introduces a Centaur V variant optimized for low orbits: about six feet shorter, carrying a third less propellant, with the saved weight traded for satellite mass.[18] ULA stacked the vehicle in its new VIF-A integration hangar and ran a wet dress rehearsal at SLC-41 on August 6, 2026.[14][19] The company entered 2026 projecting 18 to 22 launches, up to 18 of them on Vulcan; through late July, its total for the year was the USSF-87 flight plus three Atlas V Leo missions.[12]
Finances and leadership
Tory Bruno, ULA's chief executive since 2014 and the public face of Vulcan's development, resigned on December 22, 2025; chief operating officer John Elbon took over as interim CEO while the board searches for a permanent successor.[16] Within days Bruno resurfaced at Blue Origin, Vulcan's engine supplier and a competitor for its launch contracts, as president of the company's new national security group.[17]
The grounding has strained ULA's finances. Lockheed Martin disclosed in July 2026 that it had guaranteed up to $500 million in ULA borrowings and trimmed the profit outlook for its space division, while ULA pointed to a backlog of more than 80 missions awaiting flight.[12]
The BE-4 engine brought a second problem in 2026. A New Glenn first stage was destroyed in a static-fire explosion at Cape Canaveral on May 28, 2026, and Blue Origin traced the failure to the main oxygen valve on one of its seven BE-4 engines. Vulcan's version of the engine lacks New Glenn's relight and reuse features, but ULA said it would retrofit the modified valve onto its own BE-4s at its Decatur, Alabama factory and at Cape Canaveral as part of the return-to-flight effort.[13]
References
- Vulcan Centaur - Wikipedia.
- List of Vulcan launches - Wikipedia.
- Vulcan suffers solid rocket booster problem during USSF-87 launch - Spaceflight Now.
- ULA's Vulcan Centaur launches first national security mission - SpaceNews.
- Space Force Pauses Vulcan Missions amid Anomaly Investigation - Air & Space Forces Magazine.
- ULA confirms successful solid rocket booster test as Vulcan anomaly investigation continues - Spaceflight Now.
- Vulcan Centaur - United Launch Alliance.
- U.S. Space Force certifies ULA's Vulcan rocket to begin launching national security missions - Spaceflight Now, March 27, 2025.
- NASA contract confirms selection of ULA's Centaur 5 as new upper stage for the SLS rocket - Spaceflight Now, March 7, 2026.
- U.S. Space Force awards $13.7 billion in new national security launch contracts to Blue Origin, SpaceX and ULA - Spaceflight Now, April 5, 2025.
- Manufacturing defect blamed for Vulcan solid rocket motor anomaly - SpaceNews.
- ULA deals with financial challenges caused by Vulcan grounding - SpaceNews, July 24, 2026.
- Blue Origin identifies engine issue behind New Glenn explosion - Spaceflight Now, August 6, 2026.
- ULA launches final Atlas 5 rocket supporting Amazon Leo's broadband internet satellite constellation - Spaceflight Now, July 2026.
- Sierra Space's Dream Chaser debut mission delayed again, no longer docking to station - Spaceflight Now, September 26, 2025.
- United Launch Alliance chief Tory Bruno resigns - SpaceNews, December 2025.
- Former ULA president and CEO Tory Bruno joins Blue Origin - Spaceflight Now, December 26, 2025.
- Vulcan: New Centaur V version readies for Amazon Leo - United Launch Alliance, June 2, 2026.
- In Brief: ULA Completes LEO-Optimized Vulcan Wet Dress - Aviation Week, August 7, 2026.
- ULA offloads first Vulcan rocket at Vandenberg as it preps its next Cape launch - Spaceflight Now, February 6, 2026.
- Amazon Leo set to accelerate satellite production and launch cadence - Amazon.
- SLS to launch without upper stage for Artemis 3 - SpaceNews, May 13, 2026.
