Defiant class

The Defiant-class was a type of Federation starship in use by Starfleet in the 24th century. Although officially designated as an escort, the Defiant ships were the first type of starship Starfleet ever created as a dedicated-purpose warship, and they are sometimes referred to as destroyers. 

Overview
The Defiant was conceived as Starfleet's first warship in response to the many new threats faced by the Federation in the mid-24th century but primarily the Borg. The vessels were purposed as a compact design, packing a great deal of weaponry into a very small, maneuverable ship. As such, many of these vessels were fielded in battle during the Dominion War. The class has a compact warp core that produces enough energy to power a vessel four times its size. 

History
The Defiant-class was one of many new Starfleet classes developed in response to the Borg threat following Starfleet's tragic losses in the Battle of Wolf 359. The class was the first that Starfleet ever developed purely as a warship—but for years following the Borg's early incursions, the expected invasion never materialized—the prototype USS Defiant (prototype) spent much of its time in space dock in the Utopia Planitia Fleet Yards. Rising hostilities with the Dominion spurred the Defiant into full service, assigned to Deep Space 9 in 2371 and fitted with a Romulan cloaking device to defend the station from Dominion attack and conduct undercover operations in the Gamma Quadrant.

By the time the situation escalated into full-scale war, several Defiant-class starships had been put into service and performed admirably. The original USS Defiant was destroyed by a Breen energy dampening weapon in 2375.

Following the Dominion War Starfleet developed a ship based on the lessons of the Defiant-class, the first and so far only vessel of this type, the USS Incursion is fitted with a holographic masking system and is operated by Starfleet Intelligence. 

Specifications
Defiant-class vessels crewed 50 officers and crew, with room for a maximum of 150 in evacuation situations. The Defiant vessels weighed 355,000 metric tons, measured 170.68 meters in length, 134.11 meters in width and 30.1 meters in height. The Defiant had a warp core power plant rated at over 1,500 cochrane units in output, feeding two warp nacelles. The warp drive was rated for a maximum output of warp factor 9.982 for 12 hours. The ships of the Defiant-class were also fitted with two impulse engine fusion reactor plants and thrust emitters.

The vessels have ablative armor to absorb enemy weapons fire and were fitted with beam weapons consisting of four pulse phaser cannons, capable of firing from numerous phaser arrays along the hull. Defiant ships also are equipped with two launchers, capable of firing either photon torpedoes or quantum torpedoes from numerous emplacements along the hull. In an extreme situation the Defiant-class's nose section, which contained the vessels stock of torpedoes, could be separated as a last resort to act as a large projectile. 


 * In official and licensed sources alike, the Defiant is always listed as having four phasers and two torpedo launchers. Onscreen canon evidence has shown that these weapons can be fired from more numerous points along the hull.

The Defiant-class was one of the few classes of Starfleet starships capable of planetary landing and lift-off. (SS ST (Safe Harbors))

The compact type-10 shuttlecraft was designed alongside the Defiant-class and two can be held in its shuttle bay.

In the later 24th century, the Defiant-class was slated to continue production at the ASDB Integration Facility at Antares Fleet Yards shipyards, on Antares IV. (Star Trek: Deep Space Nine dedication plaque)

Like other Federation and starfleet ship designs, the Defiant-class was fitted with intercooler systems to cool the warp and impulse engines and the power transfer grid. The plasma intercooler was fitted with safeties which could be taken offline at the discretion of the ship's chief engineer. Both Miles O'Brien and Nog had performed this action, in order to coax better performance from the engines, aboard the USS Defiant (prototype) and the USS Valiant (NCC-74210), respectively. 

Known vessels

 * USS Ajax (Defiant class)
 * USS Alaska (Defiant class)
 * USS Albatross
 * USS Aldebaran (Defiant class)
 * USS Alexey Leonov
 * USS Armstrong (Defiant class)
 * USS Ark Royal (Defiant class)
 * USS Avenger (Defiant class)
 * USS Baracus
 * USS Barracuda (Defiant class)
 * USS Baton Rouge (Defiant class)
 * USS Bennington
 * USS Boxer (Defiant class)
 * USS Champion (Defiant class)
 * USS Cheyenne (Defiant class)
 * USS Cobra
 * USS Concord (Defiant class)
 * USS Condor (Defiant class)
 * USS Cormir
 * USS Corvus (Defiant class)
 * USS Crockett (Defiant class)
 * USS Dauntless (Defiant class)
 * USS Defiant (NX-74205) (I)
 * USS Defiant (NX-74205) (II)
 * formerly USS Sao Paulo (NCC-75633)
 * USS Eagle (Defiant class)
 * USS Eclipse
 * USS Falkirk
 * USS Fargo
 * USS Formidable (Defiant class)
 * USS Franklin (Defiant class)
 * USS Gallant (NCC-74206)
 * USS Galahad (Defiant class)
 * USS Gauntlet
 * USS Gawain
 * USS Grant (Defiant class)
 * USS Halberd
 * USS Havoc
 * USS Helena
 * USS Horizon (NCC-75668)
 * USS Hornet (Defiant class)
 * USS Hurricane (Defiant class)
 * USS Illustrious
 * USS Incessant (NCC-75636)
 * USS Iwo Jima (Defiant class)
 * USS Javelin
 * USS Kant
 * USS Kingfisher
 * USS Law
 * USS Lee (Defiant class)
 * USS Leyte (Defiant class)
 * USS Logan
 * USS Loki (Defiant class)
 * USS Man-o-War
 * USS Matador
 * USS Maya
 * USS Medvedev
 * USS Merrimack (Defiant class)
 * USS Michigan (Defiant class)
 * USS Mongoose
 * USS Monitor (Defiant class) (I)
 * USS Monitor (Defiant class) (II)
 * USS Monsoon
 * USS Morgana
 * USS Moscow (NCC-75655)
 * USS Myrmidon
 * USS Narcissus
 * USS Neptune (Defiant class)
 * USS Nomad
 * USS Pendragon (Defiant class)
 * USS Pleiades (Defiant class)
 * USS Potemkin (Defiant class)
 * USS Python
 * USS Quillon
 * USS Ramses (Defiant class)
 * USS Ranger (Defiant class)
 * USS Raven (Defiant class)
 * USS Redoubtable (NCC-75634)
 * USS Relentless
 * USS Renegade (Defiant class)
 * USS Revere (Defiant class)
 * USS Rockford (Defiant class)
 * USS Rome (Defiant class)
 * USS Saladin (NCC-74350)
 * USS Sao Paulo (Defiant class) (II)
 * USS Savannah (Defiant class)
 * USS Scorpion (Defiant class)
 * USS Sioux
 * USS Sirocco
 * USS Snake Eyes
 * USS Spitfire
 * USS Stalwart (NCC-75635)
 * USS Stromming
 * USS Tenacious
 * USS Thor (Defiant class)
 * USS Ticonderoga (Defiant class)
 * USS Titan (Defiant class)
 * USS Treplev
 * USS Triumph (Defiant class)
 * USS Triton (Defiant class)
 * USS Tsunami
 * USS Turin
 * USS Valiant (NCC-74210)
 * USS Valiant (NCC-75418)
 * USS Valorous (Defiant class)
 * USS Vanya
 * USS Victoria (Defiant class)
 * USS Victorious (Defiant class)
 * USS Vigilant (Defiant class)
 * USS Voltaire
 * USS Warspite (Defiant class)
 * USS Wasp (Defiant class)
 * USS Wolverine
 * USS Zeppelin

Incursion type

 * USS Incursion (NX-74808)

Mirror universe

 * The following Defiant-class starships were built in the mirror universe.


 * Defiant
 * Capital Gain
 * Jadzia
 * Terra Victor

Background
The USS Defiant first appeared in canon in.

Apocrypha
The ebook Dominion War Sourcebook: The Fires of Armageddon from Last Unicorn Games released after they had lost their Star Trek license mentions additional ships USS Victorious (NCC-66012) and USS Nemesis (NCC-72495).

Several more previously unheard-of ships of this class were described in unused code that can be decompiled from the software of the video game Legacy. These vessels include the USS MacGoohan, USS Portmeirion, USS Drake, USS Harmony and USS Grainer.