Affiliation United Federation of Planets / Starfleet
Year Beginning Service 2366
Design Specifications
Ship Type Escort
Length 119 meters
Beam 94 meters
Height 21 meters
Crew 40 (50 at most)
Tactical Specifications
Armament 4 Type XII Pulse Phaser Cannon, 2 Type X Collimated Phaser Array, 3 Photon Torpedo Launchers (All Forward)
Defenses Deflector Shields, Ablative Armor, Cloaking Device
Engineering Spefications
Top Speeds Warp 6.0 (Standard Cruising), Warp 8.0 (Maximum Cruising), Warp 9.982 (Maximum Attainable)
Impulse Engines Two Impulse Systems


The Defiant-class starship was a heavily-armed, limited-role Starfleet vessel, developed in response to the Borg threat as originally encountered in 2365, and spurred on by the shocking results of the Battle of Wolf 359 in 2367. With the knowledge that existing weaponry and defenses would be inadequate to meet this threat, it was recognized that a new type of starship was needed to meet the tactical requirements of facing this superior enemy. Shortly after the massacre at Wolf 359 in 2367, Lieutenant Commander Benjamin Sisko joined the development team at the Utopia Planitia Fleet Yards. (DS9: "The Search, Part I")

The USS Defiant (NX-74205) was the class prototype. It was Starfleet's first dedicated combat vessel, and therefore did not house provision for families or diplomatic missions, nor science labs or recreational facilities.

The Defiant-class was a heavily-armored, stripped-down starship and incorporated the latest in Starfleet weaponry and defensive technology and was equipped with a class-7 warp drive. The Defiant was considerably smaller than most other Federation starships. (DS9: "The Search, Part I")

Starfleet eventually decided to put the Defiant-class into full production. By the end of 2373, there were a significant number of Defiant-class ships in operation, and over the next two years they played a vital role in the Dominion War. (DS9 Season 7; VOY: "Message in a Bottle", "Endgame")

The USS Defiant was destroyed by a Breen warship in 2375, during the Second Battle of Chin'toka. Another Defiant-class ship, the USS São Paulo, was then assigned to Deep Space 9. Given the USS Defiant's exceptional record under Captain Benjamin Sisko's command, the Chief of Starfleet Operations gave a special dispensation to change the ship's name to Defiant. On this ship, the shield generators were completely reconfigured so that they would not be affected by the Breen's energy-dampening weapon. This new Defiant played a distinguished role in the final battle with the Dominion at Cardassia Prime, and remained stationed at Deep Space 9. (DS9: "The Changing Face of Evil", "The Dogs of War", "What You Leave Behind")

Knowledge of this class was retained well into the 31st century, as demonstrated when Captain Jonathan Archer and Lieutenant Malcolm Reed viewed schematics on the class in the 22nd century while accessing the database belonging to temporal agent Daniels. (ENT: "Shockwave")

Technical Data

Propulsion systems

The warp core spanned three decks in the aft section of the ship. The class-7 warp drive was extremely powerful for a ship of this size, and as such, Defiant-class vessels put out a warp signature equivalent to much larger starships. (DS9: "The Search, Part I", "One Little Ship")

The fastest that a Defiant-class ship has achieved independently on screen is warp 9.5, after diverting energy from the weapons' ready reserves. (DS9: "The Sound of Her Voice")

Tactical systems

Phaser cannons

A total of four phaser cannon assemblies were located in forward-facing locations on board Defiant-class vessels. The cannons were located above and below the nacelle root attachments on the main body on both port and starboard sides of the ship. (DS9: "The Search, Part I", et al.)

Phaser beam emitters

The standard phaser beam emitters aboard Defiant-class vessels served almost as a secondary supplement to the primary phaser cannon array. In all, the Defiant-class was equipped with at least three emitters: one forward and aft, as well as one behind the bridge on the dorsal surface. (DS9: "Paradise Lost", "Shattered Mirror", "The Emperor's New Cloak"; VOY: "Message in a Bottle")

The Defiant-class vessels' deflector arrays could also be refitted into a makeshift phaser emitter, providing one-shot capability in extreme emergency. The phaser emission was generated by the nose/deflector unit. (DS9: "Starship Down")

Torpedo launchers

Defiant-class vessels had a total of six torpedo launchers, four forward and two aft. The four forward launchers were located on the hull just ahead of each of the warp nacelles in dorsal and ventral pairs. (DS9: "Defiant", "For the Uniform") The two aft torpedo launchers were tucked in near the back end of the warp nacelles. (DS9: "The Die is Cast", "Paradise Lost") These torpedo launchers allowed the ship to fire both quantum torpedoes and photon torpedoes. (DS9: "Defiant", "The Adversary", etc.)

Deflector shields

The Defiant-class was equipped with deflector shields.

The most durable of its kind in all of Starfleet's shield systems' arsenal, it was quickly modified to be immune to Breen shield disruption technology.

Ablative armor

At least one Defiant-class vessel, USS Defiant NX-74205, was equipped with ablative armor. (DS9: "The Way of the Warrior", "Paradise Lost")

It was never made clear whether the ablative armor was ever added to the official Starfleet Defiant-class specification. As late as 2372, Starfleet Operations had not been informed that the Defiant had been so equipped. (DS9: "Paradise Lost")

Cloaking device

A special amendment to the Treaty of Algeron allowed the USS Defiant to be fitted with a Romulan cloaking device. (DS9: "The Search, Part I", "Defiant")

The Romulans loaned and allowed the limited supervised use of at least one cloaking device. Operation of the cloaking device was to be limited to the Gamma Quadrant and in return, the Federation would provide the Romulans any and all intelligence collected in the Gamma Quadrant and about the Dominion. (DS9: "The Search, Part I", "Visionary") The USS Defiant was the only Federation ship to be seen regularly operating a cloaking device.

It is of note, that soon after the cloaking device was brought into use the Dominion developed a way to penetrate the cloak using certain types of antiproton beams. The Defiant was especially vulnerable as the power of the warp engines in relation size of the ship led to a high power signature that wasn't fully masked by the cloaking device. It did however, at times provide a significant tactical advantage that was exploited on countless occasions. (DS9: "The Search, Part I")

Interior Design

Defiant class msd-2

Defiant Class Master System Display

Due to the militaristic nature of the Defiant-class starship, the interior design was the most spartan in Starfleet. The Defiant class had five decks.

The deck layout is from the Star Trek: Deep Space Nine Technical Manual and is largely consistent with the master systems display seen many times on-screen. In addition, three references were made to a "deck 5" during the fourth season: "The Way of the Warrior", "Rejoined" and "To the Death". The first two citations were in reference to hull breaches; the third citation had Captain Sisko traveling to "Deck 5, Section 1" via turbolift.

Main bridge

The bridge layout of the Defiant was compact, but nonetheless accommodated the familiar engineering, tactical, science, conn, and ops stations.

The main bridge acted as the nerve center of the vessel, and the entire module was sunken into a much larger deck 1 than on most Federation starships to provide added protection during combat situations. Access to the bridge was provided by two doorways at the back, located on both port and starboard sides. Just forward of the starboard entryway was the location of the ship's dedication plaque, as well as an auxiliary computer access panel.

The port side of the bridge housed the engineering and tactical I stations, while the starboard side featured the science and tactical II consoles. Because of its nearly exclusive role as a combat vessel, stations aboard Defiant-class vessels were designed with speed

in mind.

The center of the bridge featured the lone captain's chair, which was on a raised platform and had a clear view of all bridge stations, as well as of the main viewscreen. On both sides of the command chair were separate control panels, allowing the occupant access to virtually every system aboard the ship.

Between the command chair and the viewscreen was an integrated flight control and operations panel, capable of performing the joint duties of those stations' larger counterparts on other Federation starships. Like all of the bridge stations on Defiant, the conn had been designed for maximum speed and efficiency of commands input by the operator, allowing the craft to be handled almost like a fighter when under the hands of a skilled pilot.

The engineering station allowed for a direct link to the impulse and warp engines, as well as monitoring of the other various systems vital to the operation of the ship. This single station was capable of mirroring all the readouts and consoles located in main engineering, allowing the chief engineer or another engineering officer to issue commands from the bridge.

Mirroring the engineering station on the port side of the bridge was the science station. Normally occupied by the ship's chief science officer, the panels and readouts on this station allowed direct access to the ship's sensor systems. Capable of taking high resolution scans of both natural and artificial phenomena, this station played a vital role during reconnaissance missions.

Flanking both sides of the viewscreen were two tactical stations, which had primary access to the ship's powerful phaser cannons, torpedo launchers and various other special ordinance packages. Working closely with conn, the officers stationed at these consoles were responsible for firing the various weapons aboard Defiant-class vessels during combat operations. The purpose of the Tactical II station was to lighten the load on its sister station, particularly in battle.

Some time after the commission of the Defiant-class in 2371, various aspects of the bridge were redesigned. The captain's chair area was redone to remove the fencing and add new consoles, the dedication plaque was moved to the starboard door area, and addit

ional consoles were added to the side stations and the rear wall. (DS9: "Equilibrium")

Some time in 2373, Starfleet vessels were fitted with the new holographic viewscreen technology. A hologrid on the bridge could create a holo-simulation of the communique. (DS9: "For the Uniform")

Medical facilities

The main sickbay was located on Deck 2 between the mess hall and science labs. Containing four biobeds, this room served as the primary crew support facility during emergency situations. The room was equipped with limited surgical facilities and was primarily intended to stabilize patients until they could be delivered to a nearby friendly starbase medical facility.

In its limited role as a reconnaissance starship, the Defiant-class was equipped with two dedicated science and medical labs for field testing and investigations. These rooms mirrored their counterparts on larger Federation starships by making use of scaled down devices that could commonly be found on those ships. (DS9: "Broken Link")

Main engineering

Main engineering on the Defiant-class was situated on Deck 1 with the lower section on deck 2. The Master Situation Monitor was located in the starboard wall bulkhead. The warp core was placed on an elevated platform in the center of the room opposite the control consoles.

Crew quarters

Each cabin was equipped with one replicator port and one standard computer terminal. Overall, crew quarters aboard Defiant-class vessels were the most spartan when compared to other ships in the fleet.

With emphasis towar

ds the tactical systems being the foremost priority in the vessel designers' minds, crewmembers had to share their quarters with at least one other crewmate during normal times of operation. Only the ship's commanding officer was given his own room on Deck 1, which doubled as an informal ready room.

Mess hall

Ships of the Defiant-class lacked any sort of recreational facilities, and the only place for informal gathering were the two mess hall areas located on the port side of Deck 2. Like all the equipment and materials aboard the ship, the mess hall was spartan and compact. At the head of the room were three open slots that served as dispensers for the replicators. A counter extended from the underside and was used for the placement of trays, mugs and eating utensils. Seating inside the mess hall was provided by four metallic tables arranged in a semicircle at the wider end of the room. These tables were approximately one meter square, and each had four stools connected to its legs. In addition, the mess hall doubled as a makeshift meeting area that could be used to conduct crew briefings and mission profiles. A tall screen panel located on one of the walls could be used as a visual aid to display tactical graphics. (DS9: "Valiant")

Transporter rooms

Defiant-class ships were equipped with two transporter rooms, one located on deck 1 and the other on deck 2. (DS9: "Past Tense, Part I", "The Die is Cast", "The Way of the Warrior")

Ships Using This Class in Star Trek: Second Fleet Online

There are no ships of this class in ST:SFO.


Ship Information and Specifications are from Memory Alpha and Ships of the Star Fleet, Volume III

USS Defiant (NX-74205), quarter view

Defiant Class Escort

Pictures: From Paramount and CBS through Memory Alpha
Defiant class aft

Defiant Class Escort, Aft View