Star Trek: Deep Space Nine (sometimes abbreviated to ST: DS9 or DS9) is a science fiction television series set in the Star Trek universe.
The show is set in the Milky Way galaxy, approximately during the 2370s. Unlike the other Star Trek TV shows, it took place on a space station instead of a starship, so as not to have two series with starships at the same time (the starship USS Defiant was introduced in season 3, but the station remained the primary setting for the show). This made continuing story arcs and the appearance of recurring characters much more feasible. The show is noted for its well-developed characters and its original, complex plots. The series depended on darker themes, less physical exploration of space, and (in later seasons) an emphasis on many aspects of war.
DS9 premiered in 1993 and ran for seven seasons, ending in 1999. Rooted in Gene Roddenberry’s Star Trek universe, it was the first Trek spin-off created without direct involvement from Roddenberry, although he did give his blessing to the concept shortly before his death in 1991. The series was created by Rick Berman and Michael Piller, at the request of Brandon Tartikoff, and produced by Paramount Television. Key writers, in addition to Berman and Piller, included show runner Ira Steven Behr, Robert Hewitt Wolfe, Ronald D. Moore, Peter Allan Fields, Bradley Thompson, David Weddle, Hans Beimler, and René Echevarria.
A spin-off from Star Trek: The Next Generation, DS9 began while its parent series was still on the air and there were a few crossover episodes between the two shows. The station's first appearance in Star Trek: The Next Generation was during the sixth season episode "Birthright" and in addition, two Next Generation characters, Miles O'Brien and (from Season 4 onwards) Worf, became regular members of DS9.