In English, the word ''frak'' means...absolutely nothing. But in the not-so-faraway fantasyverse of Battlestar Galactica — Sci Fi Channel's critically exalted reboot of the 1978–79 TV series about space-faring humans fleeing genocidal robots known as Cylons — ''frak'' is similar to a certain FCC-unfriendly epithet that also begins with f and ends with k. Judging from a recent visit to the show's Vancouver set, the multipurpose word will be heard frequently when Galactica returns for its third season on Oct. 6 at 9 p.m. It will be used to express angst when married military man Lee ''Apollo'' Adama (Jamie Bamber) finds himself yearning for married fighter pilot Kara ''Starbuck'' Thrace (Katee Sackhoff) and mutters ''Frak me.'' It will be used to express awe once chief mechanic Gaelin Tyrol (Aaron Douglas) discovers a secret saloon inside the titular battleship and marvels, ''Holy frak!'' And it will be used to express rage after a high-ranking officer (nope, we ain't tellin') drives a pen into the neck of tortured traitor Gaius Baltar (James Callis) and screams ''MOTHERFRAKKER!''

Yep: There sure is a lot of frakkin' human drama on this sci-fi show. Sometimes there's more of it than there is actual science fiction — and that's exactly how they like it in Galactica's little corner of the cosmos. To be certain, the show has its fair share of far-out bits, like visually stunning F/X, trippy concepts (a half-Cylon/half-human baby whose blood has cancer-curing powers), and, of course, Number Six (Tricia Helfer), an immortal platinum blond Cylon partial to wearing crimson red dresses and high heels. But more than that, the show has distinguished itself as one of television's very best dramas — on a par with 24, The Wire, and Lost — because it so utterly transcends both its genre and its source material.

The original ABC series was a one-season wonder of Star Wars-era escapism that over time has attracted a nostalgic, multigenerational cult following. But this gritty new version has taken the same bleak conceit of its predecessor — the unceremonious obliteration of humanity on the peaceful planet of Caprica by cybernetic invaders — and rewired it with prickly, challenging post-9/11 relevance. No longer are the Cylons chrome-plated toasters with oscillating LED eyes — they've evolved into flesh and blood, which allows them to hide in plain sight, like, say, as a muckraking journalist (D'Anna, played by Lucy Lawless). Moreover, they're now motivated by their radical belief in one God to wipe out their creators from existence. Fortunately, the Capricans are as resilient as cockroaches.

Exactly 50,298 surviving souls soon boarded a fleet of star cruisers — led by the massive battleship Galactica — and embarked on a possibly fruitless quest for a mythical lost colony called Earth. They were led by Adm. William Adama (Edward James Olmos) and President Laura Roslin (Mary McDonnell), along with ace fighter pilots Apollo and Starbuck; once-trusted pilot — and Cylon sleeper agent — Sharon Valerii (Grace Park); and the brilliant but slightly mad scientist Baltar, whose feverish visions of Number Six propelled his unlikely ascension to the presidency in season 2. That disastrous development only led to more problems once the refugees found a home on the barren planet of New Caprica; by the finale, their bid for a new beginning came to an end when the Cylons returned.

For nonviewers, this may induce a massive headache. But the series' sophisticated stories have also attracted a distinctively new breed of fan, one who's not necessarily a sci-fi buff. ''Some of the smartest people I know are addicted to this show,'' says McDonnell. ''All it takes is one or two episodes and you're hooked.'' Though routinely snubbed by the Emmys (yeah, it stings them), Galactica recently won a prestigious Peabody award, and the affirmation has the cast and crew psyched. ''The last thing that I wanted to be doing was science fiction on cable television,'' says Olmos. ''But this, to me, is a real gift. I'll be in science fiction every day of my life if they can give me this kind of drama.''

Now, if only they could give him a bigger audience. Galactica averaged 2.3 million weekly viewers in season 2, and while that's impressive by Sci Fi's standards, conventional wisdom says its ratings could — and should — be much larger. Blame the complicated plots and the genre's fringy rep, a stigma that's only exacerbated by a glut of similar-sounding (and inferior) shows like Stargate Atlantis, Farscape, and Andromeda. Says Callis: ''It's strange to exist in the popular consciousness, but so few people actually watch the show. I can't tell you how many times I've had to tell people, 'No, we're not Stargate. Really.'''

''Our name has always been a blessing and a curse,'' says exec producer Ronald Moore. ''Now it's really a curse. We've done market research. People who would watch Nip/Tuck, The Shield — that's our audience. But the minute you say Battlestar Galactica, you can see the lights go off in their eyes.'' Adds Park: ''I can't even get my agent to watch the show. I appreciate your laughter, but it's true. Sooooo true.''

And yet. Mounting buzz and fan-generated ardor have raised hopes that a giant leap forward in popularity is at hand. At the same time, the show is about to make some of its riskiest moves yet. In a strategic shift, Galactica will return in early October — not during basic cable's usual summer-launch season — but for the first time against the broadcast networks' big guns. ''Moving to fall isn't going to hurt,'' insists Sci Fi president Bonnie Hammer. ''With the right product, we can go toe-to-toe during network season. And we truly believe Battlestar Galactica can do it.''

But this is its third season, a critical time when even the best TV series start to struggle with maintaining their creative vitality. So Moore and coexec producer David Eick are, ironically enough, ramping up some of those allegedly alienating sci-fi elements for season 3, which features an exploration of Cylon society via an extended stay inside one of their base ships. Eick, naturally, feels compelled to share some jumping-the-shark anxiety here at the moment of Galactica's breakout opportunity. ''We approach season 3 with nothing but terror, insecurity, and sheer liquid horror that we're going to screw it up if we're not really, really careful,'' he says. ''That's our mantra: Don't screw it up.''

Then again, it seems that Battlestar Galactica has actually done pretty well for itself by trying to steer prospective viewers in the other direction. When Sci Fi relaunched the franchise with a 2003 miniseries, there was certainly a ragtag band of enthusiasts — including original star Richard Hatch — clamoring for it. Since 1998, Hatch had led a charge to get Galactica's copyright owners to resume the saga via a new show. He nearly got his wish: In 2001, a concept developed by director Bryan Singer and his X-Men producer Tom DeSanto for Fox focusing on a new generation of Galactica denizens imploded after delays infringed upon Singer's commitment to X-Men United. Enter Sci Fi — and exit the whole ''continuing the saga'' idea. The network instead optioned the property with the intention of ''reimagining'' the franchise — same characters and concept; different actors and aesthetic approach — and hired former USA Cable exec Eick. He, in turn, snagged Moore, well-known in sci-fi circles for his years as an acclaimed writer and producer in Paramount's Star Trek factory. Neither man had any nostalgia for the original series; to this day, Eick still hasn't watched the entire pilot.

The faithful got their first glimpse of Galactica 2.0 at a 25th-anniversary convention organized by Hatch at a Hollywood hotel. Reports of Moore's revisionist plans had already reached and irked fans (Starbuck's now a chick?! Heresy!), so Hatch invited him over to respond to his critics. Moore accepted, and even brought clips from the still-in-production miniseries. The reaction: boos, hisses, even threats of popcorn throwing. ''At one point,'' recalls Moore, ''they asked me, point-blank, 'Will you pledge to make a different show if this goes to series?' And I said, 'No.'''

And you know what? Those angry fans all probably watched anyway: The miniseries garnered promising ratings for Sci Fi, and the series launched in January 2005 (though not until a foreign partner was recruited to help underwrite the costly enterprise). This version still has its dissenters; you can Google ''Galactica in name only'' to sample their vitriol. Most of their fury is still directed at the now-female Starbuck. Her sex change rankled diehards because of affection for original portrayer Dirk Benedict (who reportedly was going to reprise his role in the Singer/DeSanto version), and because it represented the death of a dream: to see a continuation, not a revamp, of the saga. ''At first, it totally sucked,'' says the new Starbuck, Sackhoff, of the derision. ''There were petitions on the Internet to, like, save Starbuck's genitalia. I started becoming obsessed. I'd be up until 2 a.m. after every episode, trying to figure out if I won them over. And because it takes 100 positive remarks to let go of one negative comment, I would be going, 'Okay, one more positive, one more positive… S---! It's a negative!' I was like, I've got to stay off the Internet.''

For his part, Hatch thinks they just need to get over it. ''The miniseries was very hard to watch for the original fans, and for me, not because it wasn't wonderful, but because it was so different,'' says the actor, who has a recurring role on the new Galactica as a political dissident-turned-leader. ''It's the same thing as life: We grudgingly yield to change, and ultimately realize that change is good. This Battlestar has balls. It has guts. It digs more deeply into the premise than the original ever could.'' Under Moore and Eick's watch, Galactica has thus become a TV think piece teeming with politically potent issues. Moore said he felt the very premise — a society is devastated and transformed by a catastrophic terrorist attack — demanded that the show's fiction speak to our post-9/11 environment. Embracing the opportunity, they resolved that Galactica ''was going to be about us,'' says Moore, ''about the experience that we're having right now.'' He and Eick praise Sci Fi for the freedom they've been given, although their penchant for coloring heroes with disturbing moral ambiguity (Starbuck brutally torturing a prisoner; Adama drowning a baby in a dream sequence) has sparked some clashes with network brass. ''They could be a wee bit more hopeful and aspirational,'' says Hammer. ''But it's a huge learning curve, and they're finding the right balance.''

Still, don't expect the bleak skies to clear up completely. The fleshbots may have again found their targets, but they're increasingly conflicted over their genocidal policy: They've set up Baltar as a puppet leader, and are making the New Capricans live under their boot instead of crushing them with it. Galactica's geopolitical touchstone, meanwhile, has shifted from Patriot Act America to occupied Iraq. As such, the rooting interest for viewers has become murkier. In the season premiere, for instance, human insurgents make a shocking choice to employ suicide bombers. For the actors, bringing to life this juicy dilemma was a mixed blessing. ''I was thrilled by the possibility of taking people that we know and love and seeing them put in a circumstance where anyone can become [someone] they don't want to be,'' says McDonnell. ''Shooting that particular episode, everybody looked sad, everybody felt sad. We realized we were all sort of going through the same thing: the hopelessness of an occupied nation.''

If relating to an oppressed people was rough for the cast, venturing behind the iron curtain of Galactica's oppressors was just plain weird, and not everyone believes that getting to know the Cylons is a good idea. ''My personal jury is still out,'' says Bamber. ''I think where the show really works is in the daily grind aboard the Galactica, trying to run from this unknown and therefore ultimately terrifying enemy.''

The encouraging news is that the creative gambit has been given considerable thought. To prep the Cylon actors, Moore wrote a veritable Cylon manual called ''Life on a Base Ship.'' ''It was like gold,'' says Helfer, who declined to divulge any nuggets. ''But I did share it with other actors who didn't get copies. Not any humans, mind you, just my fellow Cylons.''

For all the hand-wringing, Hammer believes the Cylon plotline enriches the provocative question at the center of season 3's stories: ''How do you know which side you should root for?'' She hopes Galactica's audience can grow this season; if it doesn't, its current ratings and network-enhancing reputation — combined with ancillary revenues from DVD sales and the hugely popular original webisodes that have netted 1.8 million downloads since launching earlier this month — still make it a very valuable asset. Sackhoff puts it in perspective: ''The show is good because we're on a smaller network that allows us the freedom to take chances. I don't know if this show could go mainstream, and if we'll get any bigger than we already are. Let them have their Grey's Anatomy, you know? We'll keep our secret to ourselves until it's time to give it up and move along.''

Like the original Galactica, this version has an implicit conclusion: the eventual discovery of Earth. Moore and Eick say they have an ending in mind, but won't say if it involves the Galactica and its fleet actually reaching our fair planet. Ask the cast, and they'll tell you (after insisting that Galactica is really about the journey, not the end...blah blah blah) about a popular joke on the set: The series' climactic scene will find the fleet being blown to bits by America's president. ''You know it's never going to end happy,'' teases Park. ''They think Earth is this magical Eden, but we all know how we treat each other here. Then again, you know the Cylons are just going to follow them to Earth and bring their little war to our backyard. So maybe it would be better all around if [the American president] ordered a nuclear strike on Galactica. That would be like the biggest 'F--- you.''' Or frak you, as it were.

Battlestar Galactica returns to the Sci-Fi channel in early October.