Time is catching up with the ageless "Star Trek" (search) franchise.

Born during Lyndon Johnson's administration, it is showing its age - and signs are in the stars that this could be the end of one of TV's longest and most popular series.

The series' fifth spawn, UPN's "Enterprise," (search) is in the ratings dumps. And even the last "Trek" movie, 2002's "Nemesis," tanked at the box office, garnering only $18.5 million its opening weekend - the lowest opening ever for a "Trek" movie.

"I think 'Star Trek' still could be viable, but I don't think it needs to be a weekly [TV] series anymore," says industry maven Marc Berman. "'Star Trek' has been around for 40 years, and we've gotten a lot out of it."

"Star Trek" merchandise, once a powerhouse, has warped into a shadow of its former self - and even the show's official publication, Star Trek: The Magazine, has folded.

UPN, in a bid to drum up more interest for "Enterprise," changed the show's title to "Star Trek: Enteprise" this year - but ratings were still off 10 percent last month versus Nov. '02.

TV Guide even ran a feature titled "How to Fix 'Star Trek.'"

So, the question needs to be: Is the franchise still viable?

"If ratings for 'Enterprise' continue to go down next season, it's going to hurt the franchise," Berman says. "They can still do a movie or a TV special if there's not a weekly series - it is and will always be a viable franchise if treated properly."

To be fair, "Enterprise" had the bad luck to open this season against the dramatic baseball playoffs - which notched the best ratings in years.

"Enterprise" has taken a further pounding from The WB's popular "Smallville," (search) its timeslot competitor Wednesdays at 8 p.m.

Series creator Rick Berman (no relation to Marc), who is notoriously press-shy, wasn't available to comment - but he did tell trektoday.com that he thought UPN didn't effectively promote the show's early start date this season.

"UPN is never going to take 'Enterprise' off," Marc Berman says. "'Star Trek: Voyager' launched UPN and gave them the advantage over The WB, and that show lasted for seven years.

"But 'Voyager' was not as popular as 'The Next Generation' (search) - and 'Enterprise' isn't as popular as 'Voyager,'" he says.

Officials at Paramount TV, which produces "Enterprise," declined to comment.