Notes : One of the most unique installations under Federation administration, Deep Space Nine started life as a Cardassian space station in orbit of the planet Bajor. Built in place by Bajoran slave labour during the Cardassian occupation of that planet, Terok Nor - as it was then known - served as a major administrative centre for the Cardassian forces as well as housing a large ore processing facility manned by Bajoran workers.  The station has no Warp or Impulse drive and is not suited to towing; it was therefore considered essentially a fixed orbital base with a very limited ability to manoeuvre in space. When the Cardassian occupation ended, they therefore had to abandon Terok Nor and its sister station Empok Nor in place.

At this time the Bajoran provisional government had neither the equipment nor the experience to run a space station like Terok Nor. In addition the intentions of the Cardassian government regarding their sovereignty were unclear to them, so the Federation was asked to take over command of the station and operate it for the Bajoran people. Starfleet appointed Commander Benjamin Sisko to run the station and he assumed command in 2369. Initially the station - now renamed Deep Space Nine by the Federation - was intended to operate as little more than an orbital port facility. The outgoing Cardassian forces had rendered the ore processing systems non-functional, while many other major systems had been badly damaged.

Fate had other plans for DS9 however; within days of Commander Sisko taking over the station a wormhole was discovered nearby. An artificial anomaly created by a race of sentient beings, this wormhole is unique in being completely stable. Chief Miles O'Brien was able to modify the stations shield system to allow it to be moved at modest sub light speed, and DS9 was moved to the mouth of the wormhole where a Bajoran officer claimed the anomaly for the Bajoran government - over the objections of the Cardassians.

Subsequently, Deep Space Nine has become a major stopping off point for traffic travelling to the Gamma Quadrant via the wormhole. The revenue generated by the station has been a great boon for the Bajoran economy, making both the station and the planet a major centre of trade and diplomacy in the region.

In 2370 the Dominion declared that the Gamma Quadrant end of the wormhole now belonged to them. In the brief battle that followed the Galaxy class USS Odyssey was destroyed. A subsequent Federation threat to destroy the wormhole if a Dominion fleet attempted to come through established a fragile stalemate. As the front line against this new threat, Deep Space Nine moved much higher on Starfleets priority list. The USS Defiant was assigned to the station and Starfleet began to assign regular starship patrols to the area.

A comprehensive programme of upgrades to the stations own armament systems was also undertaken. The original Cardassian design mounted six phaser banks and six photon torpedo tubes on small towers on the Habitat Ring. Starfleet engineers installed a Rotary Weapon System on each tower - these carried four Type XII phaser banks and four photon torpedo tubes each. An additional Fixed Weapon Emplacement on each tower carried one torpedo tube and eighteen phaser banks. In addition to this a set of Retractable Weapon Emplacements was installed - twelve on the Habitat Ring flanking the towers and a further six on the main Docking Pylons. Each of these weapon emplacements carries another single photon torpedo tube and five phaser banks.

The station got the chance to use its new weapons system in anger almost the moment it was finished when Captain Sisko rescued the Cardassian leadership from the Klingon invasion. A Klingon taskforce under Chancellor Gowron attacked Deep Space Nine in order to capture the Cardassians. In the ensuing battle several dozen Klingon warships where destroyed or severely damaged, although the heavy disruptor cannon of the Negh'Var where able to penetrate the stations shields sufficiently to land boarding parties. The arrival of Starfleet reinforcements forced the Klingons to stand down and withdraw back to Cardassian space, beginning several months of conflict with the Federation.

When the Dominion took over Cardassia and forced the Klingon fleet to retreat, Gowron reinstated the Khittomer Accords and a combined Federation-Klingon-Romulan fleet made a stand at Deep Space Nine against the expected Dominion assault. In the event, the situation proved to be a Dominion ruse designed to destroy the fleet along with the station and the rest of the system by detonating a trilithium device within the Bajoran sun. The attempt was unsuccessful, and an uneasy stand off against the Dominion ensued.

This situation lasted for less than a year; at the end of 2373 a Dominion fleet of over two hundred warships attacked DS9 in response to the Federations mining of the wormhole exit. Although the station was overwhelmed and captured, the Federation crew under Captain Sisko were able to destroy over fifty Dominion vessels during the attack, and activate the minefield to block the wormhole. In addition, whilst the Dominion was occupied at DS9 a Federation-Klingon task force launched a major attack against a large Dominion shipyard in Cardassian space - destroying the yard, the ships in dock, the supporting facilities and supplies, and the small force assigned to defend the facilities.

Deep Space Nine remained in Dominion hands for some three months before a combined Federation-Klingon fleet was able to recapture it in the battle which has become known as "the valley of Death". The station is now back under the command of Captain Sisko.