Astronaut Garrett Reisman spent three unforgettable months living in space, but after landing he ended up on a different mission of sorts aboard the fictional spaceship Battlestar Galactica.

Just weeks after his return from the International Space Station to Earth last summer, Reisman found himself on the set of Sci Fi Channel's "Battlestar Galactica," watching actors play at spaceflight as they filmed the final episode of the science fiction television series. The two-hour series finale airs Friday night.

"The whole spaceflight thing was still very fresh," Reisman, 41, told SPACE.com in a recent interview. "And then to be on the set where they're simulating it, it was pretty neat to experience."

Reisman didn't just watch. He donned the garb of Galactica's Colonial Marines for a short scene, though whether it will end up in the final cut is anyone's guess, he said.

"There's an extremely good chance that it will not even be in it at all," Reisman said, adding that the scene is not integral to the plot.

• Click here to visit FOXNews.com's Space Center.

In a Jan. 15 issue of the entertainment trade magazine Variety, Reisman described the scene and his visit to the Vancouver set. Someone throws up on him and then he dies.

"I had so much fun that day," he told SPACE.com.

Real station, fake spaceship

Reisman watched the original "Battlestar Galactica" series as a child and followed its recent rebirth, which retells the story of an immense space battleship as it protects a fleet of civilian spacecraft while fending off attacks from the robot Cylon enemy.

While he was in space, Reisman turned the lights down aboard the space station and tuned in to the new series via computer with the station's then-skipper, fellow NASA astronaut Peggy Whitson, as Galactica's commander Lee Adama tried to keep his fleet together on the road to find Earth.

The astronauts briefly spoke, while in space, with the show's producers Ron Moore and David Eick.

While watching the show aboard the station, one glaring omission came to light, Reisman said. No one was floating around in weightlessness.

"Being able to shoot across the room and fly, you just can't beat it," Reisman said. "Why would you deny yourself the incredible pleasure?"

But Reisman answered his own question as he recalled the hours of exercise he had to do each day just to stay healthy in space.

"There are actually scientific reasons you might want to do that," he said. "We have to work really hard to counteract the effects of zero gravity on the human body."

It's also a lot simpler and cheaper to film a show without constantly mimicking weightlessness, so that probably helps too, he added.

Reisman was also surprised with how similar the communications protocols on "Battlestar Galactica" are to those used between the International Space Station, its various Mission Controls in the U.S, Russia, Europe and Japan, and other spacecraft.

"There are a lot of things on the show that they got right, as far as the communications," he said, "especially the communications between ships."

Getting the word out

During his 2008 spaceflight, Reisman was interviewed for Comedy Central's "Colbert Report," but he's not the only professional astronaut to appear on television.

Other spaceflyers have appeared on a variety of shows, included the International Space Station's current commander Michael Fincke, who appeared with fellow astronaut Terry Virts in the last episode of "Star Trek: Enterprise" and had a line of dialogue.

Science fiction, Reisman said, has a very real ability to inspire the public in real-life space exploration, though his passion was sparked by NASA's Apollo moon missions.

Growing up in Parsippany, N.J, he watched Super 8 films of those missions until they wore out, then he spliced them back together and watched them again.

"Science fiction works best when it's done as an allegory," Reisman said. "That's what's so powerful about the new show. They take on a lot of contemporary issues."

Unlike the original "Star Trek" television series, which tended to portray societal issues as moral parables, the modern "Battlestar" takes a more nuanced approach, the astronaut explained.

"The new mission drives at the gray area, where you assume what's right and wrong, and it forces you to reexamine your concept of that," Reisman said. "Well, couple that with some good spaceship shoot 'em ups."

Watching the glitzy spaceships on "Battlestar Galactica" zoom through space battles while the International Space Station stays firmly locked in Earth orbit could feel a bit disheartening at times, but there was a very positive upshot, Reisman said.

"When you're on the space station, nobody is actually shooting at you," he said with a laugh. "So that's nice."

Copyright © 2009 Imaginova Corp. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.