Witnessing the End of the Enterprise?

They've gone where no one has gone before, but have they made the journey for the last time?

As Star Trek: Nemesis ads announce that "A Generation's Final Journey ... Begins," Trekkies are left to wonder if this is really the last time Captain Picard, Lt. Commander Data, Counselor Deanna Troi and the rest of the Enterprise crew will sail across the silver screen.

"There is some degree of finality to [the film's plot]," producer Rick Berman told Foxnews.com recently. "But, whether that means this is the last film for this cast, is yet to be decided."

It has been four years since the last Trek flick, Insurrection, underperformed at the box office, leaving fans concerned that the long-running franchise had lost its warp drive.

But Patrick Stewart, who plays Captain Jean-Luc Picard, said he advocated the long break.

"There was a sort of conveyor-belt feeling of all this," he said. "I benefited from [the time off]."

"[Stewart] was hoping we wouldn't be banging one out," Berman concurred. "His theory was, 'Let's let the audience wait and get a little bit hungry.'"

However, there's a limit to how many more films this cast can all make together. Many fans say the original crew outstayed its celluloid welcome. And unlike a character like James Bond, who has remained young through several incarnations, producers can't simply shave another actor's head and call him Picard.

"Bond is essentially timeless and doesn't age," said TrekToday.com editor Christian Höhne Sparborth. "But this isn't the case in the ever-developing Star Trek universe."

Each of the franchise's series and films have advanced the story of the Star Trek galaxy: The Next Generation takes place almost a century after the original series, Deep Space Nine moves the action from a starship to a space station, Voyager occurs in a different part of the universe and Enterprise is set between present day and Captain Kirk's adventures.

Still, after seven seasons on TV and four films, some Next Generation cast members say they're ready to let go of their sci-fi alter egos.

"Is [Counselor Troi] out? On a certain level, I hope so, because it is very hard to move on when you are doing this over and over," said Marina Sirtis of her telepathic Trek character. "As long as there is a thought that there is going to be another movie, you never really let go."

Others are uncertain about the future.

"I am kind of ambivalent about it, frankly," said Brent Spiner, who plays both the android Data and one of his prototypes, B-4, in Nemesis. "If this movie makes some money, then we will be back for one more. If it doesn't make the money they need, then you've seen the last of us. That's Hollywood for you."

Some fans are also looking at the future through the veil of the box office.

"If Nemesis proves a fan favorite … Paramount will seek to capitalize on one more TNG film," said Steve Krutzler, editor of TrekWeb.com. "If it does poorly at the box office, then without a doubt, we have seen the last of the Next Generation crew and characters."

As for plot, Nemesis is what screenwriter John Logan calls "an autumn story for Picard." As the captain looks to go in a different direction after 15 years with his crew, the Enterprise is called on a mysterious mission to meet with a warlord who's taken control of the rival Romulan empire.

The warlord Shinzon (Tom Hardy), is actually a younger clone of Picard himself. Brutalized by a traumatic life, the cloned Picard lacks the original's nobility — and has his own plans for the fate of the Enterprise.

While Nemesis provides a convenient exit for the cast, Spiner said there's a "never say never" attitude toward the series. After all, the death of Spock in The Wrath of Khan seemed to doom the series, but he resurfaced in several more Trek films.

Whatever the fate of the Nemesis cast, it's doubtful that the Trek universe will stop expanding, said Berman.

"The next film could have this cast or it could have a combination of this cast and people from other casts," he said. "I think there will be Star Trek movies until we are all at the home."

And fans are also optimistic about the future of the series.

"Star Trek fans seem to have a curious habit of forever declaring the franchise to be dead," said Sparborth. "But personally, I doubt Star Trek will ever cease to be."