Fox has been the number one network on television for six years in a row, thanks largely to "American Idol." But with "Idol" slipping in the ratings this year - and facing a life without Simon Cowell next year - and with other Fox hits either aging ("House") or going away altogether ("24"), the schedule the network announced for upfronts has some more urgency than usual about developing new hits.

"Glee," which was the network's biggest success story this year (when "Idol" overruns weren't messing with people's DVR recordings of it), will be asked to stand on its own in the fall, and be rewarded for that with the post-Super Bowl timeslot. "House" will lead into a pair of new dramas in fall and spring, and "Glee" and then "Idol" will be used to try to get Fox its first live-action sitcom hit since "Malcolm in the Middle" went away.

And in response to viewer complaints about the lack of songs in the Tuesday "Idol" performance show and the padding in the Wednesday results show, Fox execs allege that they're going to stretch the former out to 90 minutes on a regular basis and compress the latter to 30. Given the number of previous times Fox has reneged on its promises for a half-hour "Idol" results show, I will believe that only when three of those air in a row, and possibly not even then.

The new shows, meanwhile, have a good pedigree, including a sci-fi epic from Steven Spielberg and rookies from the creative teams responsible for "The Shield," "Party of Five," "Arrested Development" and "My Name Is Earl."

Fox's schedule - and my thoughts on it - night-by-night:

MONDAY: "24" goes away next week, and FOX will try to use "House" at 8 to turn at least one of two new dramas into a hit. In the fall, the 9 o'clock slot goes to "Lonestar," a soap opera set in the world of Texas oil that features the return of "Party of Five" creators Chris Keyser and Amy Lippman to both FOX and TV after a decade away. In the spring, "Shield" creator Shawn Ryan gets back to the world of cops with "Ride-Along," a Chicago-filmed series starring Jason Clarke from "Brotherhood," Jennifer Beals and Delroy Lindo.

TUESDAY: And here's where "Glee" gets to put on its big-boy pants. Where last fall it was paired with "So You Think You Can Dance" (which didn't do so well in-season), FOX believes (probably correctly) that "Glee" is now strong enough to stand on its own for a while with no lead-in, and so it leads off the night at 8, followed by a pair of new sitcoms: "Raising Hope," from "Earl" creator Greg Garcia, which has an eclectic cast (Martha Plimpton, Cloris Leachman and the ubiquitous, usually-homicidal Garret Dillahunt) and an odd premise (slacker has to raise the baby he didn't know he had after the mom goes to prison); and "Running Wilde," an "Arrested Development" reunion of sorts with Will Arnett as an immature playboy trying to woo childhood crush Keri Russell. (Arnett created it with "Arrested" head writers Mitch Hurwitz and Jim Vallely.) 

"Idol" is back at 8 in the spring, and FOX seems to have finally figured out a way to deal with all the time overruns: the show will now allegedly have a regular 90-minute timeslot, followed at first by "Running Wilde," and then by "Mixed Signals," a comedy about three male friends in different states of romance from "Wedding Crashers" writer Bob Fisher.

"I love the night," said FOX entertainment president Kevin Reilly. "I think it's our chance to turn on the lights again with live-action comedy." 

WEDNESDAY: "Lie to Me" was an unlikely renewal (though the show was much better this year than its ratings would suggest) and will air at 8, followed by another round of "Hell's Kitchen."

After the Super Bowl, "Glee" moves here to 9, and will be preceded by "Raising Hope" at 8 and the potentially brisk "Idol" results show at 8:30.

And whether the format changes stick or not, FOX chairman Peter Rice acknowledged that Cowell's exit after this season means "there's no bigger question we're going to have this summer." And auditions won't begin until September, in part to give the network more time to find an adequate replacement. (Of which I am as skeptical as the idea of a half-hour results show.) 

FOX scheduling guru Preston Beckman noted that, whereas last year "Glee" had a huge mid-season hiatus while creator Ryan Murphy filmed a movie, this year the show will run in originals into December, then be back in February.

THURSDAY: For the first time in a long time - possibly since the days of "Martin," "Living Single" and "New York Undercover" - FOX has returned its Thursday lineup intact, with "Bones" and "Fringe" set to air here throughout the year.

FRIDAY: "Human Target" wasn't the huge hit FOX was hoping for this spring - Reilly blamed it in part on an erratic launch that was complicated by a speech by President Obama and a football game that wasn't scheduled where FOX expected - but the show will be back in the fall at 8, teamed up with summer series "The Good Guys" (which previews Wednesday at 8), which will stay in production to make more episodes for fall. "Kitchen Nightmares" will air at 9 in the spring.

"We always try to program Friday," said Reilly, "but there are times when we're doing it with shows that aren't necessarily compatible."

(Of course, "Dollhouse" and "Terminator: The Sarah Connor Chronicles" were compatible; it's just that nobody watched either one.)

SATURDAY: Same as it ever was (other than a brief blip in the late '90s), with "Cops" at 8 and "America's Most Wanted" at 9.

SUNDAY: The animation bloc returns intact, preceded in the fall by FOX's football post-game show. In the spring, "American Dad" moves to 7:30, "The Cleveland Show" to 9:30, and the post-"Simpsons" timeslot goes to "Bob's Burgers," a new animated comedy from the team behind "Dr. Katz, Professional Therapist."

Still-to-be-scheduled is "Terra Nova," a sci-fi series about a family who travels back in time to prehistoric Earth to find a way to save the human race. On the plus side, the show is produced by Steven Spielberg, and Reilly promised cutting-edge special effects. On the minus side, Spielberg's small-screen track record isn't that strong, and Reilly said he specifically requested that some of the "24" writers - including Brannon Braga, not very popular in the fanboy community from his days at the helm of the "Star Trek" franchise - be put in charge of things. 

Alan Sepinwall may be reached at sepinwall@hitfix.com