One of the biggest running jokes in Star Trek: Lower Decks is the ship itself. The USS Cerritos amounts to a slightly sillier version of classic Star Trek vessels, with awkwardly extended warp nacelles and its registration number on the back of the saucer rather than the front. It comes from one of the franchise's most important traditions: every series' starship is unique, and is as much a character in its own way as the rest of the crew. In this case, the Cerritos is designed as Starfleet's plucky little tugboat. It's never there for the big assignments, but performs the necessary maintenance missions that keep the Federation running.
Source：https://www.cbr.com/lower-decks-uss-cerritos-starship-class/
