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Defiant Class

Size Comp
Universe : Prime Timeline
Affiliation : Federation
Class Name : Defiant Class [1]
Type : Escort [1]
Unit Run :
NCC 74210 USS Valiant - Destroyed [2]
NCC 75633 USS Sao Paulo - Renamed [3]
NX 74205 USS Defiant [1] - Destroyed [4]
NX 74205 USS Defiant [3] - Active
plus 27 others built in total. 5 have been lost in all.
Commissioned : 2367 - present
Dimensions : Length : 170.68 m [5]
Beam : 134.11 m [6]
Height : 30.1 m [6]
Decks : 4 [7]
Mass : 355,000 [8] metric tons
Crew : 50 [9], 150 evacuation limit [8]
Armament : 4 [10] x Class I rapid fire phaser pulse cannon [10]
1 [11]
x Type X phaser bank [11], total output 70,000 TeraWatts
3 [10] x Pulse fire quantum torpedo tube [10]
1 x Probe/photon launcher [10] equivalent to standard photon torpedo tube with 120 rounds
Defence Systems : Auto modulated shield system, total capacity 2,376,000 TeraJoules
Heavy Duranium / Tritanium [12] Double hull plus 20 cm Ablative armour. [13]
High level Structural Integrity Field
Warp Speeds
(TNG scale) :
Normal Cruise : 6
Maximum Cruise : 8.7
Maximum Rated : 9.5 [14] for 12 hours.
Strength Indices :
(Galaxy class = 1,000)
Beam Firepower : 1,400
Torpedo Firepower : 2,150
Weapon Range and Accuracy : 810
Shield Strength : 880
Hull Armour : 3,400
Speed : 955
Combat Manoeuvrability : 8,660
Overall Strength Index : 1,551
Diplomatic Capability : 2
Expected Hull Life : 20
Refit Cycle : Minor : 0 year
Standard : 0 years
Major : 5 years


The Defiant class was initiated in 2365 as a crash programme to develop a starship capable of fighting and defeating the Borg. The design incorporated several new weapons concepts, including the Quantum torpedo and phaser pulse cannon. The design and construction teams were briefed to produce a small, tough, simple to build vessel packing the maximum possible level of firepower [10]. A secondary aim of the project was to develop new technologies for implementation in the Sovereign project and possibly into existing starship designs.

The vessel which emerged from the design office was unlike anything ever contemplated by the Federation before. In place of the usual graceful structures, Defiant was a compact, boxy, almost ugly design. The central body is a three deck block with the a single deck bridge mounted on the top for four decks in all. The upper deck contains the bridge, engineering support spaces and some crew quarters. Deck two features main engineering, a simple medical bay, more crew quarters and the ships communal mess hall. The third deck includes the transporter room  [10]and ships storage and cargo bays and the deuterium fuel tanks. Deck four houses the ships replication storage tanks and systems, the antimatter fuel pods and the small shuttle bay [14]. The single computer core is split between decks two and three.

The navigational deflector is located in a prominent housing on the ships bow, which also contains a probe launcher. Flanking the deflector housing are a pair of torpedo tubes capable of firing both Quantum and photon torpedoes. Aft of this the nacelles are fitted directly to the main hull, flanking the bridge. Each nacelle housing includes four warp coils and two of the ships pulse phaser cannon. The nacelles supporting equipment are contained within a fifth deck which hangs below the normal four; this deck is divided into three levels of crawl way spaces. Aft of the nacelles is the aft torpedo tube, and the ships armament is completed by a turret type phaser array aft of the bridge. [10]

In mid 2367 a Borg attack was launched on the Federation. [15] The Defiant was still not completed [1], but her crew nevertheless prepared to launch the ship in a desperate attempt to inflict some kind of damage on the attacking vessel. In the event the Borg vessel was destroyed in Earth orbit by the USS Enterprise-D [15] shortly after the Defiant left Spacedock to face it.

The Defiant continued to outfit in Spacedock for several months, but serious faults in the design surfaced. Overpowered and over gunned for a ship of its size, Defiant experienced serious problems with her structural integrity during warp flight and weapons operation. With the Borg threat now less urgent, the the Defiant project was shelved [1] in favour of the new Sovereign class which was then under construction.

In 2370 the USS Odyssey was destroyed in a disastrous encounter with the Dominion. [16] The first of the Sovereign class was still months away from completion, so Commander Benjamin Sisko of Deep Space Nine requested that the Defiant be assigned to a mission to contact the Dominion leaders. The ship was equipped with a cloaking device by the Romulans in order to facilitate this mission, in return for Starfleet sharing any intelligence it gained. Despite a disappointing performance on her first mission, when she was quickly overpowered and captured [1], Defiant proved her worth as a combat vessel over the next few months. [10] The field engineering team under Chief Petty Officer Miles O'Brien have overcome her initial difficulties by re-calibrating and reinforcing the Structural Integrity Field system. [11] Although not an especially fast ship by Starfleet standards [14], Defiant is far more manoeuvrable than any vessel of comparable size at both Warp and Impulse speeds. This, combined with her inherent toughness and high level of firepower, makes the ship a formidable fighting force. Despite this, Starfleet has had a difficult time getting approval to put the ship into series production [10], due in part to the designs perception as having failed originally, but also because of political trepidation within the government over fielding a dedicated warship. Fortunately these problems have now been overcome and the Defiant class is finally in full production. [17]

The Defiant herself continued to serve at Deep Space Nine for some time [10], before being destroyed in late 2375 during the Dominion's recapture of the Chin'Toka system. Fortunately most of the crew were able to escape the ship. [4] The USS Sao Paulo was subsequently renamed to the USS Defiant in honour of this [3] "tough little ship" [18].

Colour key

Canon source Backstage source Novel source DITL speculation


# Series Season Source Comment
1 DS9 3 The Search, Part 1
2 DS9 6 Valiant
3 DS9 7 The Dogs of War
4 DS9 7 The Changing Face of Evil
5 Star Trek Deep Space Nine Technical Manual Stated on page 121
6 Star Trek Deep Space Nine Technical Manual Stated on page 121
7 Visible on the bridge Main Systems Display
8 Star Trek Deep Space Nine Technical Manual Page 153
9 DS9 3 The Adversary
10 Various Deep Space Nine episodes
11 DS9 4 Shattered Mirror
12 Star Trek Deep Space Nine Technical Manual Page 123
13 DS9 4 Paradise Lost
14 DS9 6 The Sound of Her Voice
15 TNG 3 The Best of Both Worlds, Part 1
16 DS9 2 The Jem'Hadar
17 DS9 5 Call to Arms
18 Star Trek : First Contact
Series : DS9 Season 3
Episode : The Search, Part 1
Series : DS9 Season 6
Episode : Valiant
Series : DS9 Season 7
Episode : The Dogs of War
Series : DS9 Season 7
Episode : The Changing Face of Evil
Book : Star Trek Deep Space Nine Technical Manual
Comment : Stated on page 121
Book : Star Trek Deep Space Nine Technical Manual
Comment : Stated on page 121
Source : Visible on the bridge Main Systems Display
Book : Star Trek Deep Space Nine Technical Manual
Comment : Page 153
Series : DS9 Season 3
Episode : The Adversary
Series : DS9 Season
Episode : Various Deep Space Nine episodes
Series : DS9 Season 4
Episode : Shattered Mirror
Book : Star Trek Deep Space Nine Technical Manual
Comment : Page 123
Series : DS9 Season 4
Episode : Paradise Lost
Series : DS9 Season 6
Episode : The Sound of Her Voice
Series : TNG Season 3
Episode : The Best of Both Worlds, Part 1
Series : DS9 Season 2
Episode : The Jem'Hadar
Series : DS9 Season 5
Episode : Call to Arms
Film: Star Trek : First Contact


To me, the Defiant has never made sense. She is, quite simply, far too small for the job she is supposed to do. The whole history of Trek has shown us that bigger is better - bigger ships mean more powerful weapons and more powerful shields, the two major factor in most Trek battles. Bigger ships have always been faster, as well; shuttle craft can only do very low warp speeds at best, while the original Enterprise was reputed to be the fastest ship of her day.

Defiants small size means less space for weapons, for shield generators, etc. Most of all it means less space for the warp core. Traditionally, warp cores are many decks tall - the Galaxy class warp core is twelve decks tall, the Sovereign warp core fourteen decks! Yet the Defiants warp core is only three or four decks, but is supposed to be more powerful than the Galaxy warp core. The galaxy class type 10 phaser arrays contain emitters some six metres across; Defiants pulse cannon are only about three or four metres on a side, yet four of these are supposed to put out a lot more power than the two hundred emitters which make up even one of the main arrays of the Galaxy.

Many people say one of the best advantages of the Defiant is that, being so small, she can dodge most incoming fire. But while that may be true against the likes of the Klingons, the Federation almost never misses a target - a good example being the battle between the Defiant and the Federation starship Lakota. The Lakota hit the Defiant with every single shot! It's been suggested that Worf was (a) holding back in order to avoid killing those on the Lakota, and (b) not very competent in his use of the Defiant. For the first, in my opinion holding back from hurting an opponent hardly involves sitting still and letting them kill your people in return! For the second - Worf was chief tactical officer of the Federation flagship for years, while Sisko was first officer on a Miranda class - a century old design. If anything Worfs starship combat skills should comfortably exceed Siskos.

What the show *should* have given us, in my opinion, was something Defiant shaped, about three hundred and fifty metres long, with two full-sized warp cores laid flat on their sides along the long axis of the ship. They should have used the 'deflector cannon' idea from "Best of Both Worlds", and turned that entire nose structure into one big gun.

However, my opinion counts for nothing next to on-screen canon, so I've written Defiant up as the warp speed death machine the writers have made her. The back history is pretty much canon, though I've twisted it a bit to fit in with the history I wrote for the Sovereign class.

The Defiant is a highly controversial ship in some ways. Firstly, it throws up yet another error in the DS9 TM. The book has the Defiant with a top speed of Warp 9.982, while the episode "The Sound of her Voice" establishes a more modest top speed of Warp 9.5.

But this is peanuts compared to the issue of the Defiants size. Surely it would not be so difficult to ask the creator of a Starship to set a concrete size of their ship which everybody then sticks to. Yet apparently, different departments use completely different sizes for the same ship!

Defiant is, without doubt, the biggest example of this problem. The official length of the ship is 170 metres, according to the DS9 Technical Manual. However, if we look at the ships deck plans in the back of the book, we see several illustrations of people standing on the four decks. Taking these to be about 1.8 metres tall, we get a length of about 115 metres for the ship - if it's 170 metres long then those people are 266 cm tall, or about eight feet nine inches!

Comparing the Defiant to other ships leads to all kinds of numbers. When we see the ship above a Galor in "Defiant", it appears to be about 60 metres long. This is reinforced by the battle sequence in "First Contact"; the Enterprise-E swoops past behind the Defiant. Given that the E-E is "nearly seven hundred metres long" according to Picard, the Defiant looks to be in the region of 50 - 60 metres in comparison.

On the other hand, the episode "The Sound of Her Voice" includes a shot of the hangar doors in the ships belly. Assuming the shuttle is a reasonable size, the circular doors are about 15 metres in diameter. If so, then the ship itself is about 130 metres across, and so about 170 metres long again. The episode "One Little Ship" includes a comparison with a Danube class Runabout - this ship is radically shrunk later in the episode, but we see it full size to start with - which makes the Defiant look significantly more than 170 metres long.

If you look at the inside of the nacelles of the Defiant, there are clearly visible two or three rows of lights. These look exactly like windows; if we assume that they are windows, then with a spacing of around 3.4 metres the whole ship becomes a good 8+ decks tall, and goes back to about 170 metres again.

So, what are we to believe? The DS9 TM schematics are repeatedly seen on screen, and so are canon. But so are the VFX shots which give a radically different size. It's a real mess, and there's just no way to settle it sensibly. What I've done is go with the 170 metre length, but you'd be just as correct to claim any of the other figures are true.

© Graham & Ian Kennedy Page views : 153,355 Last updated : 29 Mar 2014