The Vulcan Advisory Council was a group within the Vulcan High Command that was based on Earth during the 22nd century, and was responsible for coordinating with Starfleet Command. During the mid-2140s, it was the urging of the Vulcan Advisory Council that Starfleet Command put the NX Project on hold indefinitely, following the destruction of NX-Alpha, although Commanders Archer and Robinson were eventually successful in proving that the engine design was sound. (ENT: "First Flight")