The Defiant-class starship project was first created to defeat the Borg. Starfleet was concerned about the Borg threat to Earth and was looking for a small, maneuverable, and heavily-armored vessel with the weapons capabilities to defeat the Borg cubes. However, as the Borg threat deminished, Starfleet backburnered the Defiant project and the prototype ship was never completed. One of the designers working on the ship was Ben Sisko, who returned to Starfleet Headquarters to have the ship finished to help protect DS9 and the wormhole from the Dominion. The prototype ship, named USS Defiant after its class, was sent back to DS9 for active service. The ship was not properly tested, though, and could not properly handle the weapons power it was supposed to discharge. Chief O'Brien and his engineering teams spent a long time upgrading and changing the vessel to meet the needs of the crew and to ensure that the ship would not overload its systems. The Defiant was also equipped with a cloaking device that was lent to Starfleet by the Romulan Empire. This allowed the Defiant to become the first Starfleet vessel that was intentionally equipped with such a device which made undercover missions into the Gamma Quadrant easier and safer for the crew. The Defiant-class starships have a very unique design that is unlike the typical Starfleet vessels. The Defiant-class ships are among the smallest, with only 4 decks and minimal space devoted to crew quarters, science labs, and other non-military accomodations. The average crew compliment is less than 40 officers. There are no civilians or families aboard such vessels. The ship is composed of one hull, unlike most ships which feature a saucer-shaped primary hull and a secondary hull that houses the warp engines and deflector. This design places all of the ship's vital resources into one compact unit, making it less vulnerable to enemy attacks. The warp engines are very tight to the hull, which greatly changes the warp field geometry of the ship. Phaser pulse cannons and torpedo launchers are also built into the hull, as well as special ablative armor. The Defiant is equipped with only one small shuttlebay located in the belly of the ship. Shuttles are launched from the airlock on the underside of the vessel, allowing the Defiant's hull to block the shuttle from harm. One advantage of the ship's size and shape is that it is equipped with landing gear so that it may safely land on a planetary surface in an emergency, and should be able to lift off again. The main bridge is smaller and simpler in design; there is only one chair in the middle of the bridge for the captain, unlike two or three chairs for the rest of the command crew to sit in. The helm and operations controls have been condensed into one console at the front of the bridge. There are two tactical stations as well, to provide faster and more efficient control of the weapons systems. Main Engineering is one of the larger rooms on the ship, with an open two-story design. However, it is smaller than most engine rooms and the warp core is significantly reduced in size. The transporter rooms are also very compact, as is the medical bay. There are no holodecks or other energy-draining resources aboard the Defiant. The original USS Defiant, registry NX-74205, was destroyed by the Breen during the Dominion War. Captain Sisko and his crew were able to escape the vessel before it exploded, but nevertheless, it was a great loss to the crew. In need of a new vessel, the USS Sau Poulo was assigned to the station, and Captain Sisko was given permission to re-designate the ship USS Defiant, in honor of its originator. It is likely that this Defiant-class vessel has some improvements over the previous ship.