HOLLYWOOD — The end is in sight for “Battlestar Galactica,” and the beleaguered humans of the Twelve Colonies aren’t the only ones fretting about their survival. The executives at Sci Fi, the cable channel that has ridden “Galactica” as its esteemed flagship, will now have to carry on without her.

The final 10 episodes of “Battlestar” begin Jan. 19, and although a prequel series called “Caprica” has been locked in for 2010, that show begins with a new cast, a new story and no guarantees. Dave Howe, president of the cable station, owned by NBC Universal, said there was anxiety about losing the award-winning drama that gave Sci Fi much of its identity.

“Believe me, none of us could ever overestimate the success of ‘Battlestar’ in terms of putting us on the map with not just a critical audience but actually with a new audience,” Howe said. “I think all of us will be depressed when it’s over.”

On a recent visit to Los Angeles, Howe was plainly proud of the broader success of Sci Fi (formerly called the Sci Fi Channel), which for a considerable part of its 16-year history was known primarily as a fanboy corner of the cable dial with reruns of “The Incredible Hulk” and “Planet of the Apes.” Now the channel is in a different stratum.

“We’re at No. 5 for the year,” Howe said, “and within spitting distance of A&E at No. 4, which I think has shocked some people who have assumed that we’re so niche and narrow that we don’t even register on the Richter scale.”

The question is how the channel will make the Earth move again. Howe pointed to the series “Sanctuary,” which premiered Oct. 3 and saw its pilot finish as the night’s No. 1 prime-time cable entertainment program among adults 25 to 54, as part of the answer.

The fantasy show — about mysterious 157-year-old researcher Helen Magnus (Amanda Tapping), who tends to a refuge for magical beasties — is a symbol of Sci Fi’s eagerness to embrace new models.

“Sanctuary” began as an Internet series of Webisodes and is filmed on a virtual set of green-screen technology and CGI effects.

Howe and his team are pushing online as well and view the cable channel as just part of the hard-wiring needed to get to-day’s sci-fiand fantasy fans. Sci Fi is working on a project for a 2010 premiere that Howe calls “the Holy Grail”: The channel is teaming television writers with video-game designers to create a franchise that is both a television series and a massive multiplayer game on the Internet — the game players will help shape the show’s story arc.

Sci Fi also is making a push into scripted reality shows, such as “Estate of Panic,” on which contestants compete in a haunted house, and the delicately titled “Cash or Capture,” on which “men in black” hunt players.

If anything, Sci Fi seems to be dealing with too many ideas, with a staggering number of development deals. That might be a bit of anxious hyperactivity by a channel losing its go-to franchise. Howe clearly hopes there’s another “Galactica” in the stars.