Tomorrow night on TNT, "Babylon 5," the science-fiction fan's science-fiction series, ends the five-year odyssey its creator had always promised -- but only after an escape that would do even the most experienced starship commander proud.

For last summer, it looked as though "Babylon 5" would follow the path established by "Star Trek," although not in the way its fans would have preferred.

Just as "Star Trek" had promised, in that famous introductory voice-over from William Shatner, to take viewers on a five-year mission, "Babylon 5" creator J. Michael Straczynski had always envisioned a five-year plan for his intergalactic space station.

Unfortunately, "Star Trek" never made it past year three. And "Babylon 5," with no promise of a home beyond season four, seemed destined for the same unfulfilled fate.

"It was very iffy," says Straczynski, who spent years molding "Babylon 5" as a sort-of novel for television, with a definite beginning, middle and end. "There was definitely a very real possibility that [season four] was going to be it."

So allowances had to be made. Story lines were hurried up. A final episode, in which the fate of both Capt. John Sheridan (Bruce Boxleitner) and the Babylon 5 space station itself is revealed, was shot. The fans, as dedicated a group as ever attached itself to a television program, were left to console themselves on the dozens of Internet Web sites dedicated to the show.

And then a reprieve.

"TNT was aware that we had not finished our story yet," Straczynski explains. "They had just picked up the first four seasons for syndication, and they said, 'Well, if you're going to have a book, you should have the last chapter of it.' And they decided to go ahead and give us that opportunity."

The five-year run of "Babylon 5" ends at 10 p.m. tomorrow with "Sleeping In Light," a moving, quiet rumination on loyalty, honor, friendship and making peace with your destiny.

Watch carefully, and you'll notice a fitting detail: The last person you see on-screen, the man in whose hands rests the fate of the Babylon 5 space station, is none other than J. Michael Straczynski.

"Yeah, that's me," he says from his office in Southern California. "If anyone on the planet is going to pull that switch, it should be me."

A 44-year-old former journalist with script-writing credits that include such un-sci-fi shows as "Murder, She Wrote" and "Walker, Texas Ranger," Straczynski set two parameters for "Babylon 5." He wanted his saga of an intergalactic space station, where beings from anywhere in the universe can live and play in peace, to segue naturally from one chapter into the next. And he wanted a series that was truly science fiction, not one that only used the genre as a handy way of attracting viewers. It's that respect for the genre that garnered the show its rabid cult following.

Knows the genre

"At the networks, if you're going to do a cop show, you hire a guy who knows police procedurals," Straczynski says. "In a hospital show, you hire a guy who knows medical stuff. Traditionally, the networks have hired to do science-fiction shows guys who have done soap operas. The guy who did 'War of the Worlds' for Paramount, for instance, had come off of 'Love Boat.' They had no knowledge of the form. Same thing for the guy who did 'V.' They actually tried to say it wasn't a science-fiction show; they had great contempt for science fiction. But as long as we had the ray guns and the aliens and the funny ships, the audience would come, guaranteed.

"When you have that kind of contempt behind the show," he continues, "the stories you do will not be mature stories, they won't be character-based stories, they'll be gimmick stories, sort of like two kids and robots who fall down and make funny noises. Doing the show with a certain degree of integrity -- that's what we tried to do."

His fans say he succeeded.

"Knowing that the show would run for five years actually increased my confidence that the show would be done right, since Joe would have no vested interest in pandering to a lower common denominator," says Barbara Pfeiffer, who has her own Web page dedicated to the minutiae of "Babylon 5" (http: //www.bejay. com/b5.htm). "At its best, and there have been many classic episodes, it has the quality of classic high drama, dealing with life and death and real choices."

Adds Andrew A. Adams, who oversees his "Babylon 5" Web page (http: //www-theory.dcs.st-and.ac. uk/ (tilde)aaa/B5.Ref.html) from the U.K., "There have been some things that failed along the way, but I agree with JMS [Straczynski] that if you never fail, you're not pushing the envelope hard enough."

Fan input

And what the fans think has always been important to Straczynski. He's legendary for reading fans' e-mails and has even been known to incorporate their suggestions and criticisms into the show. Sometimes, the exchanges can get pretty spirited, as in last year's debate over the departure of actress Claudia Christian.

As Cmdr. Susan Ivanova, Christian had become a fan favorite. But with season four winding to a close and season five not yet guaranteed, Christian left. She claimed the producers forced her off the show and has posted several explanatory e-mails on various Web sites explaining how. Straczynski vehemently insists the only one who forced Claudia Christian off the show was Claudia Christian.

Regardless of who's telling the truth, the running dialogue re-inforces the notion that these fans take their show very seriously.

"But what really surprised me," Straczynski says, "is the way communities have formed around the show." One Washington fan, he notes, went so far as to post a notice on the Internet, inviting anyone and everyone to come over and watch the show on his big-screen TV.

"To do that anywhere, open up your house to total strangers, is nuts, let alone in Washington, D.C., where Jesse Helms could show up for all you know. But 50 people showed up, and they had a great time, and it became a regular thing."

Perhaps that's what makes Straczynski most proud: Like the space station at its core, "Babylon 5" has become a sort of communal meeting place.

"There's enough already out there in television, film and society that marginalizes us, tribalizes us and separates us," he says, "and not a lot that brings us together. I was surprised by the extent to which this show has achieved the goal of bringing folks together."

With "Babylon 5" already behind him -- tonight's finale, after all, was filmed over a year ago, when the show was going to end with season four -- Straczynski's already hard at work on his next series, "Crusade," with Gary Cole ("American Gothic") as the captain of a ship searching the galaxy for the cure of a plague RTC that's threatening to end all life on Earth.

"There are one or two characters [from 'Babylon 5'] who are going to pop up from time to time. It's still going to be in the B5 universe, but on B5, we really couldn't go anywhere; it's a space station show. This show is basically my opportunity to go out and explore that universe a little more.

More science

"We're trying to put the science back in science fiction, working with JPL [NASA's Jet Propulsion Laboratory] to make the show more visually interesting. Very often, science-fiction television shows, they go to a different planet with all the excitement of going to the corner 7-Eleven -- they all look like Malibu. So we asked, 'Binary star system, how would it look? If it had two suns, what would the colors be? What time would sunset be? What would the environment look like? What would the atmosphere look like? We want to create what it could actually be, how it would actually look."

He's also got a comic book in the works, a 24-issue series from Top Cow comics called "Rising Stars," about a group of people from a town in Illinois, all roughly the same age, who grow up with various superpowers.

"What's cool is they all know each other, they all grew up together. Imagine if Batman, Superman, Joker and all of them grew up knowing each other, there were no secret identities, and all their childhood problems were carried up into adulthood. How the law system would deal with this, how the authorities would deal with this -- it's a study of what happens to these people over the course of their lives."

Not that he needs another project, but was there ever any though to continuing the successful "Babylon 5" franchise beyond its fifth season?

Wonder that, and you prove you don't know Joe (that's what his friends call him) Straczynski very well.

"I know there were some folks at TNT who were much inclined toward that," he says, "but my feeling always was that the story had a beginning, a middle and an end, and to carry this particular volume of that story any further would make everything that preceded it a lie. And I wasn't willing to do that."

Farewell episode

What: "Babylon 5: Sleeping In Light" (series finale)

When: 10 p.m.-11 p.m. tomorrow

Where: TNT cable channel

Pub Date: 11/24/98