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All Federation starships I have seen have a very similar configuration. Is there any in-universe explanation for this?

I know this configuration comes from human ships like the NX-01, but why was it kept for the federation after it was formed? why not follow a Vulcan or Andorian design instead? Is there any inherent benefit of having a big round section and external engines?

I remember from an Enterprise episode that they emit some radiation that is dangerous, but there should be a way to shield it to allow a less fragile design.

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Out of universe explination would be that it helps the audience recognise who is who. And the way it looks was just an asthetic the prop designers chose during creation. – OghmaOsiris Jun 28 '11 at 13:39
Suggested speculative in-universe explanation: “We spent 18 years designing and building one starship this way, and it worked. We’d rather not spend 18 years designing and building a starship in a different way only to find out it doesn’t work.” – Paul D. Waite Jun 29 '11 at 16:16
up vote 28 down vote accepted

In-Universe, the Federation has a standard design for their warp engines, and they use a technology for power and warp travel which is somewhat different than other species use. The necessities of their design compel them to build their ships along a standard model (saucer + nacelles).

Form follows function, in this case.

There is also a unification aspect: the Federation is composed of many species, some of which are radically different, physically and physiologically. Their ship design is part of the Federation shared culture, and serves to give all the races a cultural touchpoint. The origins of this go back all the way to the NX-01 and its sister ships.

Other races seem to use different technology (or at least a different method of nacelle design) for their propulsion. Romulans, for instance, somehow harness energy from micro black holes. Thus, other species designs follow their own culture, limited by their engineering constraints.


Here's a page which includes some Star Trek starship design guidelines, including nacelle pairing (they MUST be in pairs), placement (must be visible from the front), and size. They are included in a site devoted to people designing new types (for fanfic, fan images, etc) but are purportedly from Gene himself.

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@santiagozky: None is explicitly given, though Enterprise shows that the NX-01 was CRUICIAL to the formation of the Federation, and of the 3 main races (Humans, Vulcans, and Andorians) the humans were most neutral. Vulcan and Andoria had been at war as bitter enemies for a long time, either would have been hesitant to adopt the other's ship designs. – Jeff Jun 28 '11 at 20:19
Doesn't the Defiant break those rules? – HorusKol Jun 29 '11 at 0:11
@HorusKol yes, the Defiant is a radially different design. However, while being designed the goal was to make the Defiant (and its class of ship) specifically to counter the Borg. Most likely that design goal led to some non-convential thinking in the engineering and design teams which resulted in the ship we saw. – Xantec Jun 29 '11 at 1:03
The Defiant may be a different design. But the core concept remains the same. Like all Starfleet shişs she has twin nacelles. The only difference is they are placed in the body of a ship where other ship nacelles are far away from the body. IMHO this has two consequences; One is, Defiant is a more compact and this makes her a smaller target. Because unlike other Federation starships Defiant is a pure breed warship. The second consequence is because the nacelles are closer Defaint needs to be more compact cause the warp field will be smaller. – Sinan Jun 29 '11 at 12:30
The nacelles don't HAVE to be in pairs; the Enterprise-D from the future in "All Good THings..." was retrofitted with a third nacelle in the middle of the two original ones. Maybe it was double-wide and counts as two, I don't recall. – KeithS Sep 17 '11 at 1:29

The Not-In-Universe is the trope of "Shape identifies fleet." This trope is VERY common in Sci-Fi, being obvious in Battlestar Galactica (Old and New), Buck Rogers, Star Trek, Star Wars, the whole Mecha Anime subgenre, and more.

Gene Roddenberry, according to multiple sources, said the ships must have two nacelles, with nothing between them, and a saucer; they may have a secondary hull. All of the filmed TOS ships match this except for the Tholian and First Federation ships.

In universe, it's reuse of known strategies of ship design.

This can be seen in how the last several US carrier designs are pretty much externally identical, in ways that go beyond mere practical considerations. Elevator locations, cat and arrest gear locations, and defense systems are practical; tower shape is far less a practical matter. Much of what's in the tower could be relocated, making for a smaller, less imperiled tower.

The Saucer design provides a low frontal cross section, and high deck surface. (Ignoring the illogic of having thrust run along the decks, of course.) A tubular secondary hull is similarly efficient, but puts more vertical space together than horizontal space. All federation designs seen save 3 mix these elements; the other three are special cases (the Multi-Vector Attack ship, the Warp Shuttle in TMP, and the freighter in TAS).

Further, the use of similar pattern nacelles means crew familiarity with them... likely, they also carry the same drive systems in them.

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and don't forget spares commonality and construction cost. If you can have one facility build assemblies and parts for multiple classes of ships, the economy of scale kicks in to reduce cost and you also need less warehouse space for the gazillions of spare parts (and a ship in trouble can be more easily assisted by a ship of a different class of course). – jwenting Jul 7 '11 at 6:07
@jwenting: "spares commonality and construction cost" exists out of universe too. Lots of ship models in ST have been produced by modifying existing studio models or combining parts of CGI models, due to cost or time constraints. – thkala Jul 20 '11 at 20:57
of course. didn't mention it because the original answer was in universe – jwenting Jul 21 '11 at 13:37
@thkala Except that the scale varies widely for use of the same model part. – aramis May 27 '13 at 19:54
In this vein, it seems like color also identifies fleet. Federation blue, Klingon red, Romulan green, Ferengi orange, Cardassian yellow, Dominion purple, Borg white/gray, etc. – Michael Jun 13 '13 at 18:41

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