Defiant class

## SPACECRAFT CLASS

Class development patch

The ***Defiant*-class** was a type of spacecraft developed by Starfleet in the late 24th century. It was the first vessel in over a century designed by the service that was formally classified as a destroyer.

## History

The *Defiant*-class was one of many Starfleet designs rushed to completion in response to first contact with the Borg Collective. The starship began development at the Antares Ship Yards in 2366 as part of the Perimeter Defense Directive. After the Battle of Wolf 359, the prototype was quickly procured as an urgent operational requirement and entered official testing. It was the first vessel Starfleet had developed purely as a warship since the *Perseus*-class and it was the first design to integrate the new pulse phaser cannons from its inception.

The expected Borg invasion never materialized and the prototype USS *Defiant* spent much of its time in space dock due to design flaws and issues during testing.

Rising hostilities with the Dominion threw the *Defiant* into active service and the starship was assigned to Deep Space 9 in 2371. Numerous adjustments and upgrades were made to the starship, including the installation of a Romulan cloaking device, to defend the station from Dominion attack and conduct undercover operations in the Gamma Quadrant.

The success of the USS *Defiant* gave new life to the class. Additional vessels were ordered, implementing the changes made to the class's namesake. As other *Defiant*-class starships left the shipyards they were placed in service defending Federation space and in combat in the Dominion War.

In the 2380s, Starfleet began moving away from combat starships and towards exploration and multi-purpose designs. Though active *Defiant*-class vessels were kept in service, the design was officially retired. This decision was reversed a decade later as tensions rose between the Federation and the Klingon Empire.

## Technical specifications

### Deck plan

The following was the standard internal layout of *Defiant*-class vessels.

 2
 3
 4

### Propulsion systems

Eight plasma vents, four for each warp drive unit, were situated on the dorsal side of the hull to allow for rapid ejection of warp plasma in emergency situations.

### Tactical systems

The design's defenses included ablative armor overlaying a duranium-tritanium composite hull, which was augmented by synthetic castrodium alloy structural members. The starships operated the FSQ Primary Force Field and Deflector Control System connected to 2 Gjermundbu Mod 18C Unified Deflector Field Emitter Arrays.

## Derivatives

### *Vigilant*

The *Vigilant*-class was one of two designs developed in the early 2390s in an effort by Starfleet to update the *Defiant*-class. The *Vigilant* was created by engineers at the Antares Ship Yards and began testing in 2392. The design failed to meet expectations and was not put into production, but elements of the design proved to be viable in refits of existing *Defiant*-class vessels in service.

### *Gallant*

Engineers at the Laikan Starfleet Shipyards designed the *Gallant*-class in 2392 as an update the *Defiant* design. Like the *Vigilant*-class, its performance was lackluster, but elements of the design were incorporated into refits of *Defiant*-class starships.

### *São Paolo*

Though refits using *Vigilant* and *Gallant* components had extended the service period of the *Defiant*-class, the destroyers were not keeping pace with comparable Klingon designs. As tensions rose with the Klingon Empire, Starfleet Command ordered yet another update to the *Defiant,* hoping that the success of the new *Bellerophon*-class would carry over. Engineers at the San Francisco Fleet Yards eventually presented the *São Paolo*-class in 2396. The design proved itself an able replacement for the aging *Defiant*-class and was immediately put into production.

### *Valiant*

Carrying more armor and a larger torpedo payload, the *Valiant*-class was designed to combat the threats encountered by Starfleet in the 25th century. The vessel had a stubbier nose and longer engine struts than its parent *Defiant*-class. It combined many of the elements of the other subclasses and variant to become the premiere warship fielded by Starfleet at the time.

### *Adamant*

Developed alongside the *Valiant*, the *Adamant*-class implemented elements from Project Deep Shadow.

## Ships commissioned

The naming conventions of the *Defiant*-class varied by the shipyards where vessels were constructed. Those spaceframes launched from the Antares Yards were named for adjectives associated with combat and heroism; those constructed at the San Francisco Fleet Yards were named after notable individuals and vessels; and those constructed at the Copernicus Ship Yards were named after Earth animals.

## Gallery

*Defiant*-class Master Systems Display*São Paolo* variant firing its quad phaser cannonsThe *Valiant*-subclass
## Appendices

### Connections

**Project groups:** **Union Station** (*Geneva* • *Concorde* • *Presidio*) • **Century Cruiser** (*Springfield* • *New Orleans* • *Challenger* • *Niagara* • *Freedom II* • *Galaxy* • *Nebula* • *Cheyenne*) • **Multi-Mission explorers** (*Brigid* • *Esquiline* • *Palatine*) • **Deep Shadow** (*Eclipse* • *Phantom* • *Scryer*) • **Miracle Worker** (*Scott* • *Daystrom* • *Tucker* • *Gagarin*) • **Aeronaut** (*Mercury* • *Ajax* • *Icarus* • *Shran*)

**Other named classes:** *Aegian* • *Aerie* • *Akula* • *Atlas* • *California* • *Centaur* • *Challenger* • *Cheyenne* • *Constellation* • *Constitution III* • *Crossfield* • *Curry* • *Daedalus* • *Dauntless* • *Excelsior II* • *Freedom II* • *Gemini* • *Glenn* • *Guardian* • *Inquiry* • *Iwo Jima* • *Jupiter* • *Lexington* • *Niagara* • *Obena* • *Okinawa* • *Parliament* • *Perseus* • *Pioneer* • *Ranger* • *Sagan* • *Solanae* • *Springfield* • *Turing* • *Ulysses*

**Auxiliary craft:** *Aero* • Class C • Class F • *Danube* • *Flyer* • *Gondola* • *Kodai* • *Mollard* • *Peregrine* • *Selenic* • Type 4 • Type 5 • Type 6 (Type 6A • Type 6S) • Type 7 • Type 8 • Type 9 (Type 9A) • Type 10 • Type 11 • Type 14 • Type 17 • Type 19 • *Valkyrie* • *Venture* • *Waverider* • *Yellowstone*

### Sources consulted

* Defiant class article at *Memory Alpha*.
* Defiant class article at *Memory Beta*.
* Defiant class article at the *Star Trek Online Wiki*.
* *Star Trek: The Official Starships Collection* issue 09: "U.S.S. *Defiant* NX-74205."
* *Star Trek: The Official Starships Collection* special issue "U.S.S. *Defiant* NX-74205."
* Defiant class article at *Trekipedia*.
* Vigilant Class at the *Star Trek Online Official Site* (archived webpage).
* Defiant Problems article at *Ex Astris Scientia*.
* Defiant-Class Specs article at the *Advanced Starship Design Bureau*, a website for *Star Trek: A Call to Duty*.
* *Star Trek: Deep Space Nine Technical Manual*.
* *Star Trek: Deep Space Nine Core Game Book* by Last Unicorn Games.
* *Star Trek Roleplaying Game: Starships* by Decipher, Inc..
* *Star Trek Adventures - Core Rulebook* by Modiphius Entertainment.
* *Star Trek Adventures - Utopia Planitia Starfleet Sourcebook* by Modiphius Entertainment.

### Footnotes

1. ↑ Derived from "Defiant class decks" article at *Memory Alpha* and MSD created by Tim Davies.