"Lost in Space," right?

Actually, it's " Earth 2, " a big-budget science-fiction saga that launches with a two-hour opener at 7 tonight on WNBC / 4.

"It's all in the execution," contends Michael Duggan, one of the show's three creators and executive producers. " 'E. R.' is every other medical show I've ever seen, 'NYPD Blue' is every other cop show I've ever seen. But they're beautifully executed. It's in the details: the writing, the acting, the production design. It doesn't feel anything like 'Lost in Space.' It's a lot more like a John Ford western."

In fact, " Earth 2" has a far more complicated setup than the "Swiss Family Robinson" parallels of "Lost in Space," which aired on CBS from 1965-68. As outlined in the two-hour pilot, the group consists of the survivors of an advance party for a shipload of colonists who have fled the artificial environments of space stations orbiting the polluted, all-but-uninhabitable Earth of 200 years hence.

Their ship crashes on what is thought to be a pristine planet 22 light years from Earth. They discover, however, that they have landed far from their intended site; they must trek several thousand miles to reach it, and, contrary to their research, the planet is indeed inhabited.

Heading the ensemble cast is Debrah Farentino (formerly a regular on "Equal Justice" and for several weeks last season, Kelly's romantic interest on "NYPD Blue") as Devon Adair, whom Farentino describes as "an engineer, a mother and a leader."

Adair's 8-year-old son (Joey Zimmerman) is dying of "the syndrome," a malady stemming from the total lack of any natural environment. Her somewhat subversive plan involves saving him, and others like him, by launching an expedition to colonize an Earth-like planet.

"There's nothing like a sick child to motivate a mother," says Farentino, who in real life is the parent of a 3-year-old girl.

Her fellow castaways on these cosmic shores include a mechanic (Clancy Brown)and his preteen daughter (J. Madison Wright); a physician (Jessica Steen of "Homefront"); their space pilot (Antonio Sabato Jr. of "General Hospital"); a cyborg with an encyclopedic mind (Sullivan Walker); a conniving government official (John Gegenhuber) and his wife (Rebecca Gayheart), who is the only one to have actually lived on Earth. For the first three episodes, Tim Curry ("The Rocky Horror Picture Show") will be in the cast as the only human on Earth 2 when the crew lands.

According to Duggan, the concept of " 'Wagon Train' on another planet" was an idea hatched at Steven Spielberg's Amblin Productions, which also produces NBC's other Sunday-night adventure series, "seaQuest DSV."

Duggan, a veteran of "Miami Vice" and "Law & Order," together with former "China Beach" writer Carol Flint and "Wonder Years" writer Mark Levin, agreed to develop the concept, which NBC bought within 24 hours of their series pitch.

Fans of televised sci-fi will recognize the phrase " 'Wagon Train' to the stars" as Gene Roddenberry's original premise for "Star Trek." Duggan claims the similarity was only recently called to his attention. Unlike the original "Trek" and its successors, however, Duggan says " Earth 2" will not dwell regularly on grandiose philosophical themes.

"We're basically not sci-fi writers," he says. "We're writers of ten o'clock drama. We spent a lot of time conceptualizing what the world was like that they left, and what the world was like that they're going to.

"When you insert well-rounded characters into those two worlds with the normal amount of human conflict, you come up with some good stories. They are the same as contemporary stories - they just happen to take place two-hundred years into the future. The emotional conflicts are exactly the same: fear, wonder, awe, jealousy and the other things that go into making a good story."

Those "well-rounded characters" are what attracted top-billed Farentino to the project. "This script sat on my desk for a while," she admits during a break from shooting in Santa Fe, N.M., the show's permanent location. "It wasn't something that, on the surface, sounded interesting to me." Then she read the pilot script while on vacation and was hooked.

"I've done strong female roles before," Farentino says, "but they didn't encompass motherhood or the other aspects of what being a woman is all about." Most of the other parts she's read lately are for "girlfriends, or lawyer or doctor types [that] tend to lack a feminine edge."

Farentino also loves the location shoot. A veteran hiker and self-described "outdoors person by nature," she says, "We are outside on the some of the most extraordinary locations. The first day of the pilot, we shot at 10,700 feet, and the colors are different. You understand why Georgia O'Keeffe came to this part of the world to paint."

She says this series "is about rediscovering Earth," although she hastens to add that the show, despite its pro-environmental subtext, "is not message-driven. I don't find it preachy at all. Whatever discoveries are made in the context of the storytelling are more character-related. There's no moral at the end of the story."

The last of the season's 27 new series to debut, " Earth 2" is going up against CBS' powerhouse "60 Minutes" in what Duggan candidly describes as "the worst time slot in the history of television." NBC is hoping to snag the underserved younger audience at that hour, much of which watches "seaQuest" at 8.

It's a huge financial gamble. The pilot cost around $ 9 million, according to some sources, and the weekly budget runs 20 to 30 percent higher than the average one-hour network drama. One factor was Duggan's choice of music: A 68-piece orchestra performed the pilot score by French composer David Bergeaud, which combines a grand orchestral approach with otherworldly, ethnic sounds.

Another is the variety of visual effects required, and the creatures that have been created by Greg Cannom, who has won the Oscar the past two years for "Bram Stoker's Dracula" and "Mrs. Doubtfire."

"It's not going to be monster-of-the-week," Duggan insists. "We are trying to play it as real as possible. They don't walk up and speak the King's English," as on other series that he declines to name. "They only communicate with us in certain ways, on other metaphysical planes."

Other metaphysical planes: Now that's a phrase you never heard from Will Robinson or Dr. Smith.

The Attack Of Futuristic Forays

"Earth 2" joins the ever-growing ranks of science-fiction shows on television, which is enjoying a resurgence today.

Its companion series, "seaQuest DSV," continues to chart the Sunday-night waters on NBC, opposite ABC's "Lois & Clark: The New Adventures of Superman" (although purists might define "Lois & Clark" as more fantasy than SF).

Fox has just ordered nine more episodes of its Friday superhero show "M.A.N.T.I.S." (Friday, 8 p.m., WNYW / 5) and its "X-Files" (Friday, 9 p.m., WNYW / 5) is a certifiable hit.

With the cast of "Star Trek: The Next Generation" (rerun Monday, 8 p.m., WPIX/ 11) shifting to the big screen this month, "Star Trek: Deep Space Nine" (Monday, 9 p.m., WPIX / 11) dominates the field of sci-fi shows in first-run syndication. The United Paramount network's new "Star Trek: Voyager" debuts in January with Kate Mulgrew at the helm.

Bruce Boxleitner has joined the cast of "Babylon 5" (Wednesday, 8 p.m., WWOR / 9), while Ted Shackelford stars in "Space Precinct 2040" (Saturday, 3 a.m., WPIX / 11) from former "Space: 1999" producer Gerry Anderson. - Burlingame