Perhaps it’s appropriate that among the vast array of current television options, science fiction is represented by a gaping void. Light and inconsequential sci-fi-flavored fare hasn’t been difficult to find, but there’s been a noticeable lack of dramas set on space ships and other planets — fewer still that are challenging and bold. “The Expanse” sets out to fill that gap, and various aspects of it show real promise. But if the drama is to live up to its potential, it will have to improve on its first four episodes, which awkwardly link a series of somewhat muddled stories, and introduce characters that are too often standard genre types rather than distinct individuals.

It’s to the show’s credit that it is openly political, and takes on issues of class, representation and exploitation. The narrative takes place 200 years in the future, when Mars has been settled, Earth is run by the U.N. and many of the blue-collar folks living on a series of mining outposts are looking to break away from their colonial overlords. Quite a few Belters, as they’re known, believe Earthers are living too high on the fruits of their labors, and yet out in space, there’s little love for the militaristic people of Mars, who are highly disciplined and navigating their own frosty relationship with those on the neighboring planet.

The problem with “The Expanse,” which is based on a series of books by James S.A. Corey, is that it tries to do too much at once in its opening episodes, which ultimately undercuts their overall effectiveness. Storylines about rogue elements, terrorist machinations, a missing woman and political gamesmanship are all crammed into hours that have very little room to breathe. Clearly “The Expanse” wants to set up a series of linked mysteries, but too often it ends up sketching out a set of scenarios that could have been plucked from dozens of other sci-fi serials, and yet are vague, confusing or insubstantial.

The series of incidents that unfold in the opening hours are sometimes exciting — in particular, the knockabout crew of a rust-bucket freighter go through some suspenseful and unexpected adventures (some of those are on display in the first episode, which Syfy posted online in advance of the show’s Dec. 14 premiere). But other stories on Earth and in the Belter colony Ceres feel a bit rote, in part because the people in the midst of those events aren’t always interesting in their own right.

Thomas Jane plays one of TV’s favorite types, a cynical, semi-corrupt cop. A mild twist is that he works for a private security firm, not a government entity (as in the “Alien” movies, almost every aspect of life ends up serving commercial interests, which is one reason the Belters feel aggrieved). It’s hard to say if it’s the writing or the performance that comes up short in the police storylines; it would be safe to say that neither has enough texture or depth to make Jane’s character charismatic or compelling yet. The best part of the Ceres tale is when the terrific Jared Harris turns up as an underworld boss whose genial demeanor never quite reaches his eyes.

Shohreh Aghdashloo does what she can with a stiff, underwritten role as a savvy U.N. operative on Earth, and Steven Strait is competent but little more as a freighter officer who gets pulled into a series of machinations that seem designed to turn unrest into war. Two standouts in the cast are Dominique Tipper, who plays a tough, resilient engineer, and Cas Anvar, who imbues the role of the freighter’s pilot with welcome warmth.

The charms of “The Expanse” are often in the details, like the rat that calls the dingy freighter home, or the scuzzy landlord on Ceres who doesn’t change the air filters and ends up making kids sick. Ceres’ main commercial area also looks suitably distressed and lived in, and scenes of daily life — and rebellion — on that outpost throb with the kind of vitality the rest of the series could use more of. In the main, however, the production design doesn’t set itself apart from other genre fare; the blue-and-black palette that is by now too common in sci-fi dominates, but some of the space sequences are suitably swashbuckling.

There’s enough potential here — and enough of a desire for space-set sci-fi in some quarters — for viewers to stick with “The Expanse” to see if it figures out how to tell a more cleanly assembled, character-driven story. Even as many streaming and cable dramas lean into the idea of assembling a season-long movie (a concept that, granted, sometimes leads to underpowered slogs), “The Expanse” is a bit too frantic to supply incident and telegraph rising stakes. But the stakes will only matter to the degree that its characters and allegories become complex, idiosyncratic and resonant.

In the early going, the drama is not quiet an adventurous slice of sci-fi escapism, like Syfy’s highly enjoyable “Killjoys,” nor a serious parable about power and exclusion, a la the powerful re-imagining of “Battlestar Galactica.” Trying to be both sometimes causes “The Expanse” to split the difference and ultimately seem a bit generic and perhaps overly aspirational. (And it’s hard not to wonder if a larger episode order would have alleviated some of the character and pacing problems here, but in the cable realm, 10 episodes appears to be the new standard.)

In a TV universe in which dozens of dramas are creating deeply memorable characters and mining their own allegories with exceptional skill, “The Expanse’s” sparks of life may not be enough to power it into must-see territory. To be more certain of survival in this unforgiving atmosphere, this middling space saga will have to reach a higher orbit, and quickly.

For a discussion of “The Man in the High Castle,” “Marvel’s Jessica Jones” and “The Expanse,” check out the most recent installment of the Talking TV podcast.