"I think there will be closure for Starbuck," Sackhoff says. "But I can't see her happy, in love and with babies. She's the happiest when she's alone, feeling pain and stress. She's tremendously flawed, but out of everyone she's the most human."
Battlestar Galactica begins its final season with the Cylons, rapidly evolving robots created by man, hot on the heels of humans racing towards Earth.
Starbuck has returned from the dead, saying she's been to Earth and can lead the refugees to their promised land.
The lusty, hard-living Starbuck has a complex romantic life. She's in love with two men: Apollo, the dedicated son of Galactica's commander, and Anders, a resistance fighter who may not be the man she thinks he is.
At the end of the third season, after a steamy night with Apollo, Starbuck married Anders the next morning.
But while the personal encounters can cause a viewer's set to sizzle, it's the overall theme of what it means to be human that has earned Battlestar Galactica critical acclaim, including the 2006 George Foster Peabody Award and the American Film Institute's award for outstanding programme in 2005 and 2006.
The science-fiction series has tackled such contemporary issues as genocide, biological warfare and food-supply shortages.
Sometimes, the Cylons can seem more human than their flesh-and-blood creators.
"Sharon is a Cylon. There is no human version of herself, but she reacts in some human ways," Grace Park says of her character. "Science says that emotions break down to chemicals and receptors."
In the final 20-episode season, viewers will see the humans and probably even the Cylons reach Earth.
However, in the dark tradition of Battlestar, there's more beneath the surface, and Sharon's Cylon-human hybrid child may open up a whole new avenue.
But don't expect any story lines to continue beyond the final episode. Executive producer Ronald Moore says he's not keeping the door open for movies or another season.
"The premise was that they were looking for Earth, and we had to pay that off," Moore says.
The show's writers have always had a plan for the final season but last year's writers strike gave Moore an opportunity to tweak that plan.
"I had time to catch my breath and really think about some things," Moore says. "We're still going to have an ending, not an ambiguous ending, but how we get there has been changed a little bit."
Moore said he always believed in Battlestar Galactica but was surprised by the recognition the series has garnered.
"You just get used to the idea that you'll be ignored because of the genre," Moore said. "But this series cut hard against science-fiction cliches. It was a character drama piece, not escapism, that tackled complicated matters and challenged the audience to do more than just come along for the ride.
The series so far
Battlestar Galactica begins in a distant universe where humans live on planets known as the Twelve Colonies, which have been at war with a race of robots known as the Cylons.
Created to be slaves for humans, the Cylons launch an attack on the Colonies with the help of Baltar (James Callis), a human under the influence of a sexy human-looking Cylon named Number Six (Tricia Helfer).
The planets are destroyed, but some people escape on spaceships one of which is the Galactica, an about-to-be-retired military vessel.
Admiral Adama (Edward James Olmos) leads the ragtag group in a search for a mythical refuge called Earth.
Former teacher Laura Roslin (Mary McDonnell) is the elected president.
Adama's crew includes Sharon "Boomer" Valerii (Grace Park), a pilot who turns out to be a "sleeper" Cylon.
There are numerous copies of her model, including one that gave birth to the first human-Cylon hybrid.
The season 3 cliffhanger finale revealed four surprise sleeper Cylons; a fifth will be unmasked in this, the fourth and final season.
•Battlestar Galactica screens on C4 at 8.30pm on Fridays.
