Oprah Winfrey didn’t become a dynamic cultural force and one of the most famous figures in the world by keeping her aspirations in check. The woman dreams big.

But on Saturday she takes it to a whole new level with the high-stakes launch of the Oprah Winfrey Network (OWN). No longer satisfied to be a talk-show queen, she aims to rule over a vast cable TV kingdom.

Speaking to advertisers last year, Winfrey said OWN would be a network “built on great intentions.” Its programming, she has often stated, is intended “to inspire viewers and give them hope.”

Discovery Networks reportedly is sinking $189 million into the joint venture, which will reach nearly 80 million homes right out of the gate and offer 600 hours of original fare in its first year. Few cable channels have debuted to as much hype.

Still, success isn’t assured, according to Derek Baine, an analyst for industry consultant SNL Kagan.

“Oprah has a very powerful brand name, but it’s really difficult to get people to change their viewing habits and find a new channel,” he says. “Plus, the fact that she’ll still be on her syndicated show will probably be confusing to some people.“

Paul Levinson, a professor of communication and media studies at Fordham University in New York, also strikes a note of caution. He points out that Winfrey may not be able to muster her usual clout in an era of audience fragmentation.

“It’s very difficult to be a star in one medium and transfer that star power to another,” he says. “ ... I don’t think it will be an unmitigated disaster, but I can’t see her having the same kind of impact.”

OWN launches at noon with a half-hour introduction hosted by Winfrey, followed by a weekend lineup of sneak previews. Viewers will find shows designed to help them “live the best lives possible and feed their dreams,” says Christina Norman, the former MTV president now serving as chief executive officer for OWN.

But even though the tone will be upbeat, she insists the network won’t shy away from controversy.

“We don’t want to bring people down,” Norman says. “But there will be some grit. It’s not all airy, fairy and nice.”

Here’s what you need to know about Oprah’s new venture:

n Where to find it: OWN takes over the channel space formerly occupied by Discovery Health.

n Familiar faces: The OWN lineup features several well-known Oprah disciples, including Dr. Phil McGraw, Suze Orman, Dr. Mehmet Oz, Dr. Laura Berman and Gayle King.

The latter, Winfrey’s best friend, will host a daily talk show at 10 a.m. weekdays beginning Jan. 3.

n Oprah sightings: Don’t expect to see Winfrey 24/7. She’ll be busy with her syndicated talk show until production ends in May, but will also regularly pop up on OWN.

Shell host “Master Class,” a series dedicated to prominent people sharing life lessons, and will also appear in “Season 25: Oprah Behind the Scenes,” which takes an intimate look at the making of her farewell season. Altogether, she’s committed to 70 hours on OWN.

“We’re trying to make it clear that this is not Oprah TV, it’s the Oprah Winfrey Network,” says Norman. “We see it as the television equivalent of her magazine. She may not appear on every page, but you know she was the curator for every page, and that’s why you read it.”

n A reality check: Aside from the occasional acquired movie, OWN at the outset will primarily consist of unscripted programs, some of which resemble shows on other networks.

“Your OWN Show,” for example, is an “Apprentice”-style competition from producer Mark Burnett that has 10 contestants vying to become the next Oprah, with the winner to earn a hosting gig on the network.

OWN also is plugged into the celebrity-reality craze. Shows pegged to Sarah Ferguson and Shania Twain are set for spring.

The summer will bring series built around Ryan and Tatum O’Neal and Naomi and Wynonna Judd.

n Still to come: One of the marquee names on the OWN roster is Rosie O’Donnell, who has signed a multiyear deal. But don’t look for her new daily talk show to debut until September.