These are, in theory, great times to be a Star Trek fan. Sure, the film series is currently on hiatus, its spangly attempt to reboot continuity having had, at best, mixed results. Even so, television (where Trek first found fame) has not one, but two Trek offerings. One is the official Star Trek: Discovery, which has just kicked off its second season. The other is the ersatz Trek, Seth MacFarlane’s The Orville, which is several episodes into its own second season.

Both of these series have struggled against a sense that they’re not really Star Trek. It’s an easy accusation to face in the case of The Orville, which was born out of MacFarlane’s love of all things Trek, but despite its often juvenile humour, it regularly harks back to the era of The Next Generation in its storylines and characters. Discovery‘s task as the latest incarnation of official Trek is, if anything, tougher, because treading on fans’ hallowed ground is a sure route to a firing squad at the first sign of deviation from the holy canon. And the first series of Discovery provided plenty of ammunition for those kinds of fans.

But just what is genuine Star Trek anyway? Can there be any such thing for a franchise that’s spread across six main TV series (not counting the animated series) and more than a dozen movies? How do those former offerings inform the Trek and Trek-like shows we’re getting now? Let’s take a look.

The Original Series: Born out of the remnants of 1950s golden-age science fiction and the optimism of the 1960s, Star Trek set the template in a lot of ways. “Its five-year mission, to explore strange new worlds, to seek out new life and new civilisations,” is still what people think of when they think of Star Trek. But even Star Trek wasn’t Star Trek at first. The pilot famously had a different captain (Pike) and though the core trio of Kirk, Spock, and Bones was in place when the series began, the rest of the multicultural crew took time to fill in. Even so, the sense of exploration and of encountering the strangeness of outer space was always at the heart of the show.

The Movies (Original Cast): Though the original show died after three seasons and 79 episodes, it never really went away. Fan culture grew up around it, and the massive success of Star Wars in the late 1970s made its rebirth a real possibility. Once again though, Star Trek changed over time. The first movie had a lot of the original series’ wonder but lacked any fun and action. The second movie, the much-loved Wrath of Khan, and especially the fourth, The Voyage Home, redefined the template around the original crew, casting them as wisecracking renegades, with heavily emphasis on fan nostalgia. Sometimes it worked wonderfully, but often it didn’t—the rule of even-numbered movies being good and odd ones bad held for a surprisingly long time.

The Next Generation: Born as the original-cast movies were at their height, The Next Generation (TNG) was an attempt to recreate the original series for, well, a new generation. By any measure, it was a massive success, but once again it took time to become itself. Its multicultural crew now included an alien and an android, as well as more than one woman, but it took a step back from the action of the movies at first. Only with the introduction of the Borg as an adversary with real thematic heft did TNG take flight. Likewise, the intellectual Picard was a contrast to the action-hero Kirk of the movies but not quite so far from the curious, emotional Kirk of the original series, showing just how the sense of what Trek was had divided. Moreover, just as the movies were telling an ongoing story, The Next Generation started to move away from single-episode stories towards longer arcs—a trend that would continue in both Star Trek and television series in the wider world.

Deep Space Nine: If TNG was an attempt to recreate the Original Series, Deep Space Nine (DS9) was an attempt to do something different. Different from Star Trek anyway—its resemblance to the contemporaneous series Babylon 5 was widely noted. In this series, humans were almost in a minority, acting as peacekeepers between multiple alien races. Actively political compared to previous series, it still suffered the Star Trek curse of taking time to become itself. Uncomfortably bumpy at the start of its run, it remains deeply loved by its fans, not least because it leaned into its own strangeness, mysticism, and character relations. An ever-increasing focus on long-running story arcs allowed it to develop real depth and the stories it wove to have massive payoffs across its seven seasons.

Voyager: By the time Voyager showed up, Star Trek was suffering from diminishing returns. TNG had just ended, DS9 was still running, and several more movies were released during its run. Like DS9, Voyager had a fascinating concept: a misfit crew flung across the galaxy trying to make their way home. Unlike DS9, Voyager never quite managed to make the most of that concept; unlike earlier Trek series, it never quite became itself. It had its high points, but the possibilities of a long-form story were largely ignored, and the characters remained mostly bland remixes of what had gone before. Kate Mulgrew’s Captain Janeway was easily a match for any prior lead, but her own crew’s voyage never inspired.

The Movies (Next Generation cast): With the original cast aging out of being action heroes, the obvious step was to replace them with the popular TNG crew. And at this stage in its evolution, Star Trek was nothing if not obvious. The Next Generation crew would get four swings at the ball, but only one of those proved to be a strike. Generations was a clumsy handover from the old to the new, giving Kirk an underwhelming death that spin-off media has done its best to retcon ever since. First Contact brought back the Borg in fine style, as well as plenty of the signature Trek optimism that TNG had done so well, delving into Trek history with a time-jumping plot that raised memories of The Voyage Home. Insurrection was mostly forgettable, though it wasn’t as bad as it is remembered, being mostly an expanded Next Generation episode. It was Nemesis that killed the franchise at the movies, flinging too much CGI at the screen and criminally underusing a young Tom Hardy as it stumbled through an action-oriented plot and chickened out of the one interesting character move it made.

Enterprise: At this point, the travails of Voyager and the movies had clearly spooked Star Trek’s guardians, because Enterprise was a weird mishmash of familiar elements, shoehorned into Trek continuity. With Scott Bakula (best known for the Quantum Leap series) at the helm as Captain Archer, the show centred around a previously unmentioned USS Enterprise, from the early days of Trek’s Federation. This put it in the odd position of being a step back from earlier series, as its crew was more homogenous and its world building was largely restricted to “first encounters” with already established bits of Trek lore. In the latter half of its four-season run, Enterprise did push towards becoming itself, rather than warmed-over Trek bits, but it was too little, too late. Enterprise died in a final episode that just reiterated everyone’s affection for other, better Trek series, and with it ended 18 consecutive years of Trek on TV.

The Movies (Kelvin crew): Once again, Trek was resurrected at the movies. This time, under the stewardship of JJ Abrams, the outcome was a reboot rather than a continuation. A new Kirk, Spock, and Bones inhabiting a glittering universe of action and drama, with wisecracks and high-flying action as standard. There was some of the Trek optimism in the new movies but little exploration, and in recreating the original series there was little room for anything new. The presence of Leonard Nimoy’s Spock in the first movie just drove that point home, as did the second movie, Into Darkness, a ham-fisted recreation of The Wrath of Khan. While the third film, Beyond, was altogether more joyful and interesting, it still hewed to the action and explosions formula. The three films made plenty of money at the box office but perhaps not enough, because whether or not they’re going to come back again is up in the air at this point.

So we’ve had many different versions of Trek, born from the original series and spinning its ideals of exploration, optimism, and camaraderie in different ways. TNG succeeded in bringing back those values twenty years after the original, and DS9 successfully transplanted them to a very different setting, but every other Trek has had more limited success. Voyager never quite settled on an identity of its own, and that failure likely pushed a subsequent sense that sticking with already known Trek lore is the best idea. That need for familiarity is poison to a franchise that was once about discovery and the new, and Enterprise suffered from a fatal dose, for all its efforts to find its own identity as other Treks had done before it. Then there’s the movies: the blockbuster need for spectacle and action leaves little room for the wonder of the universe, though the one thing that the movies have consistently succeeded at is evoking the camaraderie between the various crews.

So we now have both Discovery and The Orville now on their second seasons, having spent both of their first seasons finding their feet. First-season Discovery took a lot of chances: shoehorning the story into existing Trek lore, set a few years before the original series, gave it little room to manoeuvre. Its season-long story arc was packed full of deceptions, and its sense of discovery was limited to the story of the war it revolved around. For all that, it was entertaining, with interesting characters trying and occasionally succeeding in building relationships as the plot and character revelations overturned things every other episode.

The Orville was a lot more predictable in its first season, using a Trek-like setting to tell Trek-like stories, leavened with Seth MacFarlane’s frat-boy humour and jokes about alien bodily functions. There was no ongoing story to speak of, but the show did make a gradual effort to deepen its characters as it went. Even so, it rarely hit levels that TNG had managed on its off days, and its sense of being Trek-lite was pretty solidly confirmed.

With the arrival of the second season, not much has changed for The Orville. It’s matured to the point where it’s a fun watch, and the juvenile humour has eased to the point where it won’t put off someone who can’t stand that kind of thing. It stands or falls by the strength of its characters though, as there’s no ongoing plot and only a paper-thin universe to inhabit. Luckily the cast is generally appealing, so it’s likely to hang around and maybe become even more Trek-like in its ability to find itself.

Second-season Discovery is a very different beast. The first episode of season two was an exhilarating left turn from the darkness and deceit of season one. With the arrival of Anson Mount’s Captain Pike, transferring across from the USS Enterprise to the USS Discovery, and the provision of a genuine scientific mystery to explore, this feels closer to the core of Trek than any series in years. Yes, it’s still shoehorned into existing Trek lore and filled with CGI and action sequences, but if one episode can be any indication, there’s a real sense that Discovery has figured out what worked about season one and decided to build on that. An increased focus on crew and camaraderie and the joy to be found in exploring the wonders of the galaxy seems to have been transplanted into the heart of the series. Maybe it’s just me, but that seems pretty hopeful.

And isn’t hope what Trek is really all about?