The Cygnus subclass was a class of Federation starship in operation during the 23rd century, the third batch of Hermes class starships built. Unlike its Hermes and Monoceros class predecessors, the Cygnus was specially outfitted to serve as a diplomatic and command courier Like the Hermes, the Cygnus consisted of a saucer section and nacelle, each similar in exterior design to that of a Constitution-class vessel of the 2260s. Its configuration was significantly different, however, employing only a single nacelle.