The Vulcan Centaur, usually called Vulcan, is a two-stage rocket built by United Launch Alliance (ULA) to launch national-security and commercial payloads. It is the rocket ULA designed to replace its older Atlas V and Delta IV vehicles with a single, more capable launcher. Its main customer is the US government, and it is certified to fly the country’s most sensitive satellites.
ULA, a joint venture between Boeing and Lockheed Martin, built Vulcan for two reasons. It needed one modern rocket to take over the jobs of two aging ones, and it needed an American engine to replace the Russian-made RD-180 that powered the Atlas V. Both goals shaped the design, from the engines up.
What Powers the Vulcan Rocket
Vulcan’s first stage is powered by two BE-4 engines, built by Blue Origin. The BE-4 burns liquid methane and liquid oxygen, and each one produces a large amount of thrust, so two are enough to lift the rocket off the pad. Choosing the BE-4 solved the RD-180 problem, giving ULA a US-made engine and ending its reliance on a Russian supplier for its main-stage power.
For heavier payloads, Vulcan can add solid rocket boosters to the sides of the first stage. These strap-on boosters come in configurations of up to six, and each set adds thrust at liftoff, so ULA can match the rocket to the mass of the payload rather than flying one fixed size. That flexibility lets a single core cover a wide range of missions.
The second stage is the Centaur V, powered by two RL10 engines that burn liquid hydrogen and liquid oxygen. The Centaur design has a long flight history on earlier ULA rockets, and this upgraded version can restart in space and coast for hours. That endurance lets it place satellites into high or precise orbits that need more than one engine firing. For how these engine types differ, see how rocket engines work.
Where Vulcan Came From
Vulcan exists to solve a supply problem as much as an engineering one. For years ULA’s workhorse was the Atlas V, a reliable rocket with one awkward dependency: its first-stage engine, the RD-180, was built in Russia. As relations with Russia worsened, relying on a Russian engine to launch American national-security satellites became a political liability, and Congress moved to end it. ULA needed a new rocket with an American engine, and Vulcan is the answer.
At the same time, ULA flew a second rocket, the Delta IV, whose heavy version could lift the largest government payloads but cost far more to build. Running two separate rocket lines was expensive, so ULA folded both roles into Vulcan. With its solid-booster options, a single Vulcan can cover the light Atlas V missions and, in its most powerful setup, the heavy payloads that once needed the Delta IV Heavy. Consolidating to one vehicle was meant to cut ULA’s costs and simplify its factory.
What the Vulcan Rocket Launches
Vulcan is built first for national-security space, meaning the satellites the US military and intelligence agencies rely on. It is certified by the US Space Force to launch these missions, a status that requires a rocket to prove it can reliably deliver payloads worth billions of dollars into demanding orbits. That certification is the reason Vulcan exists, since ULA’s core business is government launch.
Alongside defense work, Vulcan carries commercial payloads. Its largest commercial customer is Amazon, which contracted many Vulcan flights to help deploy Project Kuiper, a constellation of internet satellites. Mixing government and commercial flights keeps the rocket busier than defense missions alone would, which helps spread its fixed costs across more launches.
Reuse and the Vulcan Approach
Vulcan is mostly expendable as of 2026, which sets it apart from a rocket like the Falcon 9 that lands and reflies its whole first stage. Each Vulcan flight discards its core stage after use. ULA took a different bet than full booster recovery, choosing an expendable core it can build at a steady rate rather than a reusable one that needs to be caught, inspected, and flown again.
ULA has described a middle path it calls smart reuse, which would recover only the first-stage engines rather than the entire booster. The engines are the most expensive part of the stage, so the idea is to detach the engine section, bring it back, and reuse it while discarding the cheaper tank structure. As of 2026 that system is a concept and is not flying, so Vulcan remains expendable in practice.
The tradeoff behind that choice is worth understanding. Recovering a whole booster, the way SpaceX does, saves the most hardware but costs payload capacity and demands fast, cheap refurbishment to pay off. Recovering only the engines saves less per flight but keeps the rocket simpler and avoids reserving propellant for a landing. For a company whose flight rate is lower than SpaceX’s, an expendable core with a possible engine-recovery add-on is a bet that reuse only pays with high volume. Whether that bet holds depends on how often Vulcan ends up flying, which the government and commercial order books will decide.
How Vulcan Fits Among Other Rockets
Vulcan sits in the heavy-lift class and competes most directly with SpaceX for US government launch contracts. The two companies split national-security missions between them, which gives the government two independent rockets in case one is grounded. That redundancy is a deliberate policy rather than an accident of the market. The Space Force wants at least two providers so a problem with one rocket cannot halt every launch, and Vulcan and Falcon 9 fill those two slots today.
The two rockets reflect different bets. Vulcan is expendable and built around a hydrogen upper stage that can loiter for hours, which suits the demanding, high-orbit missions national security often needs. Falcon 9 recovers and reflies its booster, which favors high cadence and low cost per flight. Neither approach is strictly better, and the government’s choice to fund both is a way to keep the strengths of each available.
| Feature | Vulcan Centaur |
|---|---|
| Builder | United Launch Alliance |
| First-stage engines | Two BE-4, from Blue Origin |
| Upper stage | Centaur V, two RL10 engines |
| Reuse as of 2026 | Expendable, engine recovery proposed |
| Main customers | US Space Force, commercial |
Vulcan replacing the Atlas V and Delta IV also retired the RD-180 engine from US service, a change driven as much by supply politics as by engineering. To see where a heavy-lift rocket like Vulcan fits among small, medium, and super-heavy classes, the launch-vehicles guide lays out the categories. For the current Vulcan configurations and flight record, check ULA’s own Vulcan page.