"Star Trek: Lower Decks" focuses on the support crew serving on one of Starfleet’s least important ships, the USS Cerritos, which is plagued by a host of sci-fi anomalies. The ship’s bridge crew consists of Captain Carol Freeman, Commander Jack Ransom, Lieutenant Shaxs and Doctor T. Ana. It is the second animated spin-off in the franchise, following the 1973-74 “Star Trek: The Animated Series.” but it has a decidedly more adult tone and humor.