Summary
Star Trek: Voyager broke from the tradition of referring to starships with "the," setting a new standard for the way people speak about famous starships.
Voyager is distinct in that its name coincides with the show, much like Star Trek: Enterprise, which also omits "the" when referring to their ships.
Contemporary Star Trek series, like Star Trek: Discovery, continue Voyager's naming convention by seldom including "the" before the ship's name, although other ships outside of show titles still utilize "the."
In Star Trek: Voyager, it is uncommon to hear the USS Voyager being called "the Voyager," which differs from previous series in terms of how the starships were referenced, both within the show and in reality. In Star Trek: The Original Series, it was established to always use "the" when talking about the USS Enterprise NCC-1701. Star Trek: The Next Generation followed suit with the Enterprise-D, consistently referring to it as "the Enterprise," and Star Trek: Deep Space Nine featured "the Defiant" as its primary starship.
However, the Intrepid Class USS Voyager is always referred to simply as Voyager, without any embellishments. Star Trek: Enterprise continued this pattern by omitting "the" when referencing its experimental NX-01 Enterprise. Similarly, Star Trek: Discovery, the first series to air after Enterprise, also uses the starship's name, Discovery, without the preceding "the." Thus, it can be deduced that Star Trek: Voyager set a new standard for how people discuss the renowned starships in the Star Trek universe.
Why Voyager Isn’t Called “The Voyager” In Star Trek
Voyager stands out among other Starfleet vessels because it is the first starship to have the same name as the show it appears on. Star Trek: Deep Space Nine set a trend by naming subsequent Star Trek series after their main locations, and Star Trek: Voyager follows this pattern as it is set aboard the USS Voyager. Similarly, Star Trek: Enterprise takes place on the NX-01 Enterprise. Both Enterprise and Voyager drop the use of "the" when referring to their respective ships in conversation, making it clear that they are different from the Enterprise in Star Trek: The Original Series or Star Trek: The Next Generation.
In the show, Star Trek: Voyager is never referred to with "the," so including it when mentioning the starship, as they did in early episodes, sounds odd and even incorrect. In the third episode of Season 1, titled "Parallax," the crew discovers a ship they are trying to assist is actually their own starship. Lieutenant Tom Paris (Robert Duncan McNeil) exclaims, "It's the Voyager!" when they see it on-screen. McNeil himself acknowledges how strange it sounds in the corresponding episode of the Delta Flyers podcast, where he and co-host Garrett Wang (Ensign Harry Kim) playfully make "the Voyager" into an ongoing joke.
Modern Star Trek Has Embraced Voyager’s Naming Tradition
The first show in Star Trek's modern era, Star Trek: Discovery, continues the tradition set by Star Trek: Voyager. Taking place primarily on the USS Discovery, the show is appropriately titled. Similar to Voyager and Enterprise, Discovery is seldom referred to with the definite article "the" before its name. In season 3 of Discovery, when Commander Michael Burnham (Sonequa Martin-Green) becomes separated from her ship, her goal is to reunite with Discovery, without the need for a definite article.
However, in modern Star Trek shows, if a ship's name is not in the title, "the" is still used with the ship names. In Star Trek: Prodigy, Dal R'El (Brett Gray) and the Diviner (John Noble) compete for control of "the Protostar." In the season 1 finale of Star Trek: Lower Decks, "No Small Parts," Ensign Brad Boimler (Jack Quaid) is thrilled to see "the Titan" when Captain William Riker (Jonathan Frakes) and his crew come to assist the USS Cerritos. Even the ship La Sirena, Captain Cristóbal Rios's (Santiago Cabrera) vessel in Star Trek: Picard, uses the definite article, albeit in Spanish. The names of future Star Trek ships remain to be seen, but if they are shared with their respective shows like Star Trek: Voyager, it is likely that "the" will not be used.