Star Trek: 10 Secrets Of Deep Space 9 You Need To Know

10. DS9's First Appearance

Star Trek: The Next Generation's season six two-parter "Chain of Command" was initially intended to crossover with Star Trek: Deep Space Nine's first year, featuring a visit to the station and a guest appearance by Quark. However, release schedules changed, placing "Chain of Command, Part I" well before DS9's premiere, requiring the removal of Quark and any explicit references to the new show.

However, while the scenes that were intended to take place aboard the station were shifted to the planet Torman V, Star Trek: Deep Space Nine's sets were nevertheless used to film the episode. In the episode, undercover Picard, Worf, and Crusher go to a seedy bar on Torman V to meet with Daimon Solok (Quark's replacement in the script), with the production utilizing a redressed version of DS9's replimat set.

As "Chain of Command, Part I" aired nearly a month before DS9's "Emissary", this is the first on screen appearance of space station Deep Space 9, despite its use as another locale in the Star Trek Universe.