Sci Fi Channel is grounding "Stargate SG-1," the longest-running science-fiction series on U.S. television to date. The cable network has decided not to order additional episodes beyond the show's current 10th season, but it has picked up a fourth season of its more-popular spinoff, "Stargate Atlantis."

"Stargate SG-1," based on the 1994 movie starring Kurt Russell and James Spader, spent its first five years on Showtime -- which annoyed the show's producers by demanding full-frontal nudity -- before migrating to Sci Fi. Its 200th episode aired last Friday. "Having achieved so much over the course of the past 10 years, Sci Fi believes that the time is right to make this season their last on the channel," Sci Fi said.

The show's ratings have softened in recent years and series star Richard Dean Anderson left last season, but it boasts a strong fan base, with as many as nine official conventions taking place worldwide every year. Producer MGM is exploring the possibility of taking the series to yet another outlet. "MGM has tremendous amount of confidence in 'Stargate,' and we are vigorously working to continue the franchise," studio spokesman Jeff Pryor said. The final three episodes of "Stargate SG-1" are slated to air on Sci Fi Channel next year. Both "Stargate SG-1" and "Atlantis" also run in syndication.