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 contain liquid methane and oxygen propellant rather than the Delta IV's liquid hydrogen and oxygen.

The versions of the Vulcan rocket range from 0 to 6 side boosters on the first stage and standard or long fairing configuration, according to customer needs. You may see a configuration "Vulcan Centaur" listed below, this is a placeholder configuration we use for unknown missions.