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 remained in place in mid-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 expects to begin delivering redesigned motors by the end of the year,[6][25] while ULA retrofits its BE-4 engines with a modified oxygen valve.[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] On August 17, ULA named Mark Peller, the executive who led Vulcan's development, as its president and chief executive.[32]
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.[1]
Unusually for a new rocket, Vulcan is not reusable, but ULA is developing a partial recovery scheme called SMART reuse (Sensible Modular Autonomous Return Technology). Instead of landing the whole booster, the aft thrust structure, carrying the two BE-4 engines along with fluid systems and avionics, would detach after staging and descend under an inflatable hypersonic decelerator and parachutes for recovery from the ocean. ULA has argued the approach recoups its cost within about two flights of a given engine set, against roughly ten flights for propulsive booster landing. Tory Bruno, then ULA's chief executive, said in August 2025 that the design had passed component and system critical design reviews, that the company planned to fly SMART-related experiments in 2026, and that recovery might arrive bundled with planned BE-4 thrust upgrades in a block upgrade of the vehicle; he also said ULA had a second reuse project it was not yet ready to describe.[23]
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. Each BE-4 produces 550,000 pounds-force of thrust at sea level, and each GEM 63XL, a 71.8-foot graphite-epoxy composite motor, peaks at 459,600 pounds-force over a burn of about 90 seconds.[7] The Centaur V upper stage, a 5.4-meter-diameter evolution of the long-serving Centaur, burns liquid hydrogen through two RL10C engines of 24,000 pounds-force each; the RL10 line behind them has logged more than 500 flights and 800 firings in space.[7] The stage 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]
The flight rate has run far behind ULA's plans. Bruno told reporters in late 2024 that 2025 could bring as many as 20 ULA launches, split roughly evenly between Atlas V and Vulcan; the year closed with six, five of them Atlas V and a single Vulcan.[30] Vulcan itself flew twice in 2024, once in 2025, and once in 2026 through late August.[2][30] The slow ramp has drawn Pentagon complaints since before the certification: Frank Calvelli, then the Air Force's space acquisition chief, wrote to Boeing and Lockheed Martin in May 2024 that "there is military satellite capability sitting on the ground due to Vulcan delays."[30]
National security role
The national security certification Vulcan earned in March 2025 carries most of the rocket's business case.[8] Vulcan was designed around the National Security Space Launch program from the start: in August 2020 the Pentagon chose ULA over bids from Northrop Grumman and Blue Origin for the larger share of the program's Phase 2, roughly 60 percent of the missions ordered over five years, with SpaceX taking the rest.[28] In April 2025 the Space Force assigned ULA 19 of the first 54 missions in the follow-on Phase 3 Lane 2, contracts worth about $5.4 billion, alongside 28 missions for SpaceX and 7 for Blue Origin.[10] The annual order books have leaned the other way: across the first two batches of Lane 2 assignments, announced in April and October 2025, SpaceX received 12 of the 16 missions and ULA 4.[29] Vulcan's first national security 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]
The grounding cost Vulcan a mission almost immediately. In March 2026 the Space Force moved the final GPS III satellite, SV-10, from Vulcan to a SpaceX Falcon 9 to keep the navigation constellation on schedule, giving ULA in exchange the USSF-70 mission, planned for 2028 and originally assigned to Falcon Heavy; Falcon 9 flew the satellite on April 21.[26][27] The service also weighed returning Vulcan to flight in a configuration with no solid boosters at all, which would allow lighter payloads such as Space Development Agency satellites to launch while the nozzle work finished. "If it doesn't rely on solids, there's no reason why we can't launch," Lieutenant General Philip Garrant, head of Space Systems Command, said in April.[24]
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] The failures have been expensive for the booster's manufacturer, which recorded a $71 million charge against the GEM 63XL program in the first quarter of 2026 and another $91 million in the second; Northrop chief executive Kathy Warden said in July that a component redesign had been proven in a static-fire test and that deliveries of the redesigned motors should begin by the end of the year.[24][25] The Space Force pause remained in place through mid-August, leaving Vulcan with a single flight in 2026 and no announced date for its next national security launch.[12][32]
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] Sierra Space finished Tenacity's prelaunch qualification checks at Kennedy Space Center, including the acoustic testing that closed its last launch-certification requirement, and by May 2026 was completing thermal protection closeouts at its Colorado factory, with the landing moved to Vandenberg Space Force Base and later Dream Chasers being pitched at national security demonstrations and satellite servicing.[31]
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] Amazon and the Space Force together account for about 90 percent of ULA's mission backlog.[30] 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 built a dedicated processing lane for the Amazon work at Cape Canaveral, stacking the vehicle in its new VIF-A integration hangar on a second launch platform, VLP-A, reserved for Leo missions, and ran a wet dress rehearsal at SLC-41 on August 6, 2026.[14][18][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.[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 board's months-long search ended on August 17, 2026, when it promoted Mark Peller, a ULA employee since the company's 2006 formation who led Vulcan's development from inception through certification, to president and chief executive; Elbon retires at the end of the year.[32][33]
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] Boeing disclosed a similar guarantee of its own on July 28.[32]
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]
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