Vulcan Centaur is a two-stage-to-orbit, heavy-lift launch vehicle developed by the United Launch Alliance (ULA). It is principally designed to meet the critical launch demands of the US government's National Security Space Launch (NSSL) program for use by the United States Space Force and US intelligence agencies for national security satellite launches.

Vulcan is ULA's first launch vehicle design; it adapts and evolves technologies that were developed for the Atlas V and Delta IV rockets of the USAF's EELV program. The first-stage propellant tanks have the diameter of the Delta IV Common Booster Core but will contain liquid methane and liquid oxygen propellants rather than the Delta IV's liquid hydrogen and liquid oxygen.

The versions of the Vulcan rocket range from 0 to 6 side booster in the first stage and standard or long fairing configuration, according to the customer's needs.