The saucer, nacelles, pylons and hull were interchangeable with Cerberus-, Hephaestus- and Prometheus-class starships. Phaser cannons were standard equipment on these ships. An enhanced version, the fleet advanced escort, was available for vice admirals. These vessels were usually commanded by an officer holding the rank of one-star rear admiral or higher. The Phoenix-class was a type of Federation advanced escort starship in Starfleet service in the early 25th century, a subclass of the Prometheus design. Federation shuttlecraft, MVAM sections Alpha, Beta, Gamma