One of the most historically, politically, and strategically important space stations in the Alpha Quadrant during the latter half of the 24th century, Deep Space 9, originally known as Terok Nor, was an orbital space station constructed by the Cardassians in orbit of Bajor during their occupation of the planet. Under Federation administration, following the Cardassian withdrawal and relocation to the Bajoran system's denorios belt, DS9 became a vital commercial port and defensive outpost due to its location near the mouth of the Bajoran wormhole. It later became a key strategic location during the Dominion War, for both the Dominion and the Federation Alliance.
Terok Nor was the station's original Cardassian designation. Built by Bajoran slave labor during the Occupation of Bajor under the leadership of the Cardassian Union between 2346 and 2351, its original purpose was to serve as a refinery for uridium ore that was mined from Bajor's surface, a process carried out in temperatures as high as 55 degrees Celsius. Therefore, Terok Nor had extensive ore refining and transport facilities that occupied the large docking pylon structures and was built to accommodate up to seven thousand humanoid-sized people as well as process up to twenty thousand tons of ore a day. The station also served as a command post from which the Cardassian Prefect of Bajor, most notably Gul Dukat, oversaw the military aspects of the Occupation. In one of his recorded messages for the counter-insurgency program installed on the station, Dukat described Terok Nor as being "a paradise" compared to Bajor. Like the planet it orbited, the station operated on a twenty-six hour day.