It's been three seasons since viewers in the Tennessee Valley have been able to follow the adventures of the USS Voyager's wayward crew. Not only was the ship lost in the Delta Quadrant, but it also was missing from area TV screens.

ABC network affiliate WAAY Channel 31 dropped the program when UPN, the upstart network carrying "Star Trek: Voyager," insisted Channel 31 carry more of the UPN line-up.

Now the Valley has its own, full-time UPN affiliate, WHDF UPN 15, and "Voyager," in its sixth season, is back.

If you've lost track of the happenings aboard the USS Voyager during its local absence, don't worry. Not much has changed. Plus, you can catch repeats of past episodes weeknights at 10 on UPN 15.

Here is a quick rundown of what you may have missed: Kes, the annoying alien played by Jennifer Lien, left the show at the beginning of the 1997-98 season. She evolved into a powerful but no less annoying energy creature and struck out on her own.

That's one annoying "Voyager" character down, Neelix, Tuvok, Capt. Janeway and Ensign Kim to go.

Kes' replacement, on the other hand, is the best thing ever to happen to the show.

It's easy to be cynical about the decision of "Star Trek: Voyager's" producers to bring Seven of Nine, played by Jeri Ryan, aboard the USS Voyager. So I will.

Since Ryan joined the cast, Seven of Nine's face and body have graced the cover of nearly every science fiction publication in North America -- proof, as if there were any doubt, that sex still sells.

Clad in skin-tight jumpsuits, Seven of Nine stalks the Voyager's corridors like a feral predator. She has the proportions of a life-size Barbie doll and the lips to match. She is every fanboy's dream girl, almost as if the computer geeks from "Weird Science" created her from scratch.

Add to that Seven of Nine's cold, logical demeanor, which stems from her having once been assimilated by Trek's perennial baddies, the Borg, and you have sci-fi television's first dominatrix.

As a character, Seven of Nine seems conceived for only one reason: to draw viewers to "Star Trek: Voyager" by any means necessary.

Sex on "Star Trek" is nothing new. The original "Star Trek" series is still known for the short skirts and go-go boots worn by the USS Enterprise's female crewmembers. And if the rumors are true, Gene Roddenberry's original vision for "Star Trek: The Next Generation" was a bit on the risqué side as well.

What is surprising is that Seven of Nine is one of "Star Trek's" most engaging characters, whatever Ms. Ryan's, um, assets.

"Star Trek: Voyager" has a well-deserved reputation as the least of the "Star Trek" series. For most of its run, it has been a jumble of all of post-Roddenberry Trek's worst tendencies. "Voyager" substitutes technobabble for science. It recycles old plots and rarely lets an episode end without re-establishing the status quo ante. And the only alien life forms the Voyager encounters are the not-so-alien ones, who look like humans with bad skin.

But just in the last season and a half, "Voyager" has improved. It's still hit and miss, and at its best it's only as good as middling "Star Trek: The Next Generation," but "Voyager" has finally clawed its way, if partly by attrition, to the top tier of current sci-fi shows, along with the likes of "Farscape" and "The X-Files."

Seven of Nine has been a major part of "Voyager's" improvement. Seven-centric episodes like "Survival Instinct," in which Seven of Nine encounters three other Borg desperate to attain individuality, show that "Voyager" has potential.

Even "Fair Haven," one of "Voyager's" all-too-common holodeck episodes, is a surprise.

Unlike virtually every other holodeck episode since the first season of "The Next Generation," "Fair Haven" doesn't involve improbable computer malfunctions. (Why, if holodecks are potentially so dangerous, doesn't Starfleet build more failsafes into them?)

Of course, it's still a holodeck episode, and it has all the flaws that entails. (Wouldn't we all rather see the Voyager crew explore strange new worlds than play in imaginary ones?) But it gives you the impression that the show is heading in the right direction.

Mind you, "Voyager" still has its share of duds. Last week's "Virtuoso" comes to mind, and next week's episode, guest starring The Rock from the World Wrestling Federation, fills me with fear and loathing.

In any event, "Voyager" is back. And it's worth at least a second look.