An early Earth starship with a long spine and two large rings in place of nacelles, known only from pictures and models of famous ships named Enterprise.
The Enterprise XCV 330 has never appeared in a story, yet it has been part of the background since 1979. In Star Trek: The Motion Picture, Commander Decker shows Ilia a row of pictures on the recreation deck tracing earlier ships of the name, and the ringship hangs between the space shuttle and Kirk's first Enterprise.
The design, by Matt Jefferies, came from an abandoned 1970s project. It turns up again as a picture on the wall of the 602 Club in the Enterprise episode First Flight, and as a model in Admiral Marcus's collection in Star Trek Into Darkness.
Its ring layout resembles Vulcan ships of the 22nd century. Nothing has been said on screen about its date, crew or history.