Star Trek: Deep Space Nine (sometimes abbreviated to DS9) is a science fiction television series set in the Star Trek universe in the Milky Way galaxy, in the years 2369–2375. In contrast to the setting of the other Star Trek TV shows, it takes 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).

The show is noted for its well-developed characters, original and complex plots, and religious themes, and for starring the only black captain in any of the televised incarnations of Star Trek. The series often showcased 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 until 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 was produced by Paramount Television. Key writers, in addition to Berman and Piller, included showrunner Ira Steven Behr, Robert Hewitt Wolfe, Ronald D. Moore, Peter Allan Fields, Bradley Thompson, David Weddle, Hans Beimler, and René Echevarria.

DS9 began while Star Trek: The Next Generation was still on the air and there were a few crossover episodes between the two shows. The station’s first appearance in TNG was during the sixth season episode “Birthright”. In addition, two Next Generation characters, Miles O’Brien and (from Season 4 onwards) Worf, became regular members of DS9. The station also appeared in the Star Trek: Voyager pilot episode, “Caretaker”.

https://en.wikipedia.org/wiki/Star_Trek:_Deep_Space_Nine