Final Orbit for "3rd Rock"?

In what's been a season of tough competition and mediocre ratings for the Emmy-winning sitcom, 3rd Rock is now in danger of getting canceled. Producers, fearing the show might get canned without a proper send-off for the Solomon clan, had a series finale written, and last week, Lithgow proclaimed to a studio audience, "You may be witnessing history here tonight."

Which means when February sweeps begin Thursday, 3rd Rock's fate could be in the balance. It marks the last time the series will have a chance to prove itself: Starting March 6, the sitcom (normally in reruns during that time) will be replaced for two months by the new Brian Dennehy comedy, The Fighting Fitzgeralds.

3rd Rock will return for May sweeps, in what could either be the season finale, or the grand finale. NBC reps say the network expects to make a final decision regarding the Carsey-Werner series in March.

"I think generally, people [here] are prepared for a cancellation," says executive producer Christine Zander--who, along with Bonnie and Terry Turner, Jason Venokur and David Goetsch, helped turn the bizarre premise about aliens on an Earthbound mission into one of NBC's signature comedies.

"It was probably the beginning of December when we said, 'We need to make a decision,' " she adds. "As far as the end of the series, we needed to be prepared and write a finale and go all out if it did happen. But if it didn't, we could always write our way back in."

The season (and/or series) finale was shot January 23, and Zander says it had all the makings of a bittersweet farewell. Songwriter Elvis Costello, a self-proclaimed fan of the show, flew in from Sweden with his wife to serenade the cast with a rendition of "Fly Me to the Moon"--part of an extravagant going-away party Lithgow and his alien family throw for themselves by maxing out their earthly credit cards.

The show wraps with Lithgow and costars French Stewart, Joseph Gordon-Levitt and Kristen Johnston leaving the planet in the same convertible they arrived in.

Since its debut in January 1996, 3rd Rock has been, in Zander's words, "a soldier to send in when [NBC] wants us to fight a battle." The sitcom, also costarring Jane Curtin, has run in 18 different time slots during its 138-episode lifespan--more than any other show in TV history. And this season, 3rd Rock has had the unenviable task of both following the now-canceled Michael Richards Show, and competing head-on with ABC's juggernaut Who Wants to Be a Millionaire.

Currently, 3rd Rock airs on Tuesdays at 8 p.m. as a lead-in for the rookie comedy DAG. This season, the series has been trounced by Millionaire and CBS' military drama JAG, with the sitcom averaging some 8.3 million viewers (5.8 rating and 9 share in households). 3rd Rock's fate may already be sealed, but some network sources suggest that the show could survive if it has a strong run during February sweeps.

The show will wrap up in May with a four-episode arc that includes the return of former Monty Python man John Cleese, who reprises his guest-starring role to compete with Dick (Lithgow) for the affection of Mary (Curtin)--and subsequently tries to turn Earth into Planet Monkey World.

Meanwhile, 3rd Rock's stars are already spreading their wings elsewhere. Lithgow has signed on to do a yearlong Broadway musical, Sweet Smell of Success. In addition to his burgeoning career as an ad pitchman, Stewart has just begun shooting a sci-fi thriller called Clockstoppers. And 19-year-old costar Gordon-Levitt was at the Sundance Film Festival last week for his new film Manic, the story of a California psych ward for teens, costarring Don Cheadle.

Zander believes that, creatively, the series has remained strong and could continue. But she adds the cast, the writers and the crew are willing to accept whatever the network decides.

"I think everyone is prepared to move on if they have to, knowing that we did what could be a great finale," she says. "I think everyone feels very positive about the show, because it is a great experience, and I think they actually were all prepared to do it again.

In the meantime, she says, "It's a wonderful goodbye...or 'to be continued.' "