Defiant class starship

The Defiant-Class is a fictional class of starship in the television series Star Trek: Deep Space Nine, Star Trek: Voyager and the feature film Star Trek: First Contact. The Defiant-class was designed by James Martin under the direction of Herman Zimmerman and Gary Hutzel and introduced to the TV series Star Trek: Deep Space Nine in its third season.

History and design
The Defiant class vessel is one of Starfleet's most advanced ship designs, conceived in response to the Borg threat. In the Episode "The Search", the Defiant Class is officially designated as an "escort" ship, which Captain Sisko noted was due to Starfleet policy of not operating warships.

Starfleet's Advanced Starship Design Bureau at the Utopia Planitia Fleet Yards began the project in 2366. Benjamin Sisko was also part of the project. After the Borg threat was deemed lower, research and production for these vessels slowed. Engineering problems – particularly in regard to the small ship's overpowered engines – led Starfleet to mothball the project. However, in 2371 Starfleet put the class into full-scale production as a response to the Dominion War.

The design is a semi-saucer fore with a squared-off aft section and measures 120 meters in length with 4 decks, making it much smaller than most Federation starships. A short, rectangular extension houses the navigational deflector and the main docking port at the bow. The 1.5 megacochrane warp nacelles are housed on either side of the ship. Unusual for Starfleet vessels, the Defiant class' nacelles are not parallel; their axes intersect less than a ship-length aft of the starship. The Defiant class was also described as "overpowered" for her size during her trials.

Another trait distinguishing this class is that it was specifically designed for war, boasting among its armaments distinctive phaser pulse cannons seemingly unique to the class. Ablative hull armor, added to the design after its launch, allows Defiant class ships to take a considerable beating even after the incapacitation of its active deflector shields. (DS9 "The Way of the Warrior", "Paradise Lost"))

The ship has few of the creature comforts that are normally found on most Starfleet vessels and has small racked bunk-styled quarters. The infirmary is small and the design does not include science labs. The standard crew complement for the Defiant class is forty-six personnel.

Known Defiant class starships

 * USS Defiant (NX-74205) : The class pathfinder built at the Antares Fleet Yards. The Defiant is assigned to space station Deep Space Nine in 2371 to help protect the Alpha Quadrant from the growing threat from the Dominion. The Romulan Star Empire equipped the ship with a cloaking device for use on intelligence-gathering missions in the Gamma Quadrant. In addition to engaging the Dominion's Jem'Hadar, the Defiant also sees action against Breen, Cardassian and Klingon vessels. The ship is severely damaged while fighting the Borg at the Battle of Sector 001 in 2373 and is destroyed in 2375 after attempting to stop the Dominion and Breen from retaking the Chin'toka system during the Dominion War.


 * The Defiant retains "NX" in its registry even after the class enters mainstream production. This may be due to the continued presence of the Romulan cloaking device, a feature not shared with the Defiant's sister ships.


 * USS São Paulo (NCC-75633) : Assigned to Deep Space Nine after the Defiant's destruction and rechristened as the USS Defiant. The studio did not wish to spend the time or money to redo stock effects shots of the Defiant used to depict this new vessel. As such, exterior shots of the ship include the registry number "NX-74205".


 * USS Valiant (NCC-74210) : Used by Starfleet cadets of Red Squad and destroyed by the Dominion in 2374. The only survivors are Jake Sisko, Nog, and Cadet Dorian Collins (DS9: "Valiant").


 * Four unnamed Defiant class ships are among the task force that the IKS Rotarraan and the USS Defiant join following Starfleet's withdrawal from DS9. (DS9 "Call to Arms")
 * Two unnamed Defiant class ships are among the task force sent to recapture the starship Prometheus in Star Trek: Voyager's "Message in a Bottle".
 * Two unnamed Defiant class ships are among the task force sent to intercept a Borg sphere emerging from a transwarp aperture near Earth. Following the emergence of the USS Voyager from the debris, the unnamed Defiant-class starships assisted in escorting Voyager back to Earth in the series finale of Star Trek: Voyager, "Endgame"