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. Introduced in January 2024, it replaces both the Atlas V and Delta IV 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]
The rocket has flown four times through June 2026 and delivered every payload to its intended orbit, but two of those four flights experienced nozzle failures on their strap-on solid boosters. After the second such anomaly, on the USSF-87 mission in February 2026, the US Space Force paused Vulcan national security launches while the problem is corrected, stalling a manifest that includes dozens of missions for Amazon's Leo constellation and the Pentagon.[2][3]
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. A version of Centaur V is also slated to serve as the upper stage of NASA's Space Launch System beginning with Artemis V, following NASA's 2026 cancellation of the Exploration Upper Stage.[1][2]
| 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 | About 15,300 kg |
| Launch sites | SLC-41 Cape Canaveral; SLC-3W Vandenberg (in preparation) |
Launch history
| Flight | Date | Payload | Outcome |
|---|---|---|---|
| Cert-1 | January 8, 2024 | Astrobotic Peregrine lunar lander | Success |
| Cert-2 | October 4, 2024 | Mass simulator | Success (booster nozzle anomaly) |
| USSF-106 | August 12, 2025 | NTS-3 and national security payloads | Success |
| USSF-87 | February 12, 2026 | GSSAP surveillance satellites | Success (booster nozzle anomaly) |
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. 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 the US Space Force certified Vulcan for national security launches in March 2025.[1][2]
National security role
That certification carries most of Vulcan's business case. ULA holds the majority of missions in Phase 2 of the National Security Space Launch program and a large share of Phase 3, and its 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 booster nozzle, 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. As of the end of June 2026 Vulcan had flown once in 2026 and its return-to-flight date had not been announced.[6]
Dream Chaser and Amazon Leo
Two commercial customers dominate the future manifest. Sierra Space's Dream Chaser Tenacity, a winged cargo spaceplane, is booked to fly its first resupply mission to the International Space Station on a Vulcan in the VC4L (long fairing) configuration, currently targeted for late 2026. Amazon holds 38 Vulcan launches for its Leo broadband constellation (formerly Project Kuiper), the largest block of the largest commercial launch purchase ever made; the first, carrying about 40 satellites on a six-booster VC6L, has been planned for September 2026, subject to the anomaly investigation. ULA has already lofted Leo satellites on its remaining Atlas V rockets while Vulcan production scales toward a planned tempo of roughly two launches per month by the late 2020s.[1][2][6]
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.
