Star Trek: Deep Space Nine (sometimes abbreviated to ST:DS9 or DS9) is a science fiction television program that premiered in 1993, ran for seven seasons, and ended in 1999. Rooted in Gene Roddenberry’s Star Trek universe, it was created by Rick Berman and Michael Piller, at Brandon Tartikoff's request, and produced by Paramount Pictures. The main writers, in addition to Berman and Piller, included showrunner Ira Steven Behr, Robert Hewitt Wolfe, Ronald D. Moore, Peter Allan Fields, Joe Menosky, René Echevarria, Richard Manning, and Hans Beimler.
A spin-off of Star Trek: The Next Generation, DS9 began while its parent series was still on the air, and there were several crossover episodes between the two shows. In addition, two Next Generation characters, Miles O'Brien and Worf, became regular members of DS9.
However, unlike its predecessor, DS9 often broke the rules laid down by Roddenberry, such as the prohibition against interpersonal conflicts between the main characters. Also, unlike the other Star Trek programs, DS9 took place on a space station instead of a starship. 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 also depended on darker themes, less physical exploration of space, and an emphasis (in later seasons) on many aspects of war.
Although DS9's ratings were initially solid, it was never as successful as Star Trek: The Next Generation, with ratings declining in later seasons. A number of reasons were given for this decline, including an increasingly crowded television marketplace (Babylon 5 aired about the same time, mining similar themes), cannibalization of viewership between it, Star Trek: The Next Generation and Star Trek: Voyager, and viewer fatigue. Nonetheless, it remained the top-rated first-run syndicated drama series throughout most of its run.