Why did Starfleet choose saucer-shaped starship design?

Question

Phoenix (the first warp ship of humanity) wasn't saucer-shaped (Star Trek: First Contact).

Enterprise NX-01 was the first to make first contact with species other than Vulcan. As Enterprise NX-01 already had saucer design, only Vulcans could influence the design if we consider inspiration from other species (Vulcans were holding back info about other species).

I think, "inspiration from Vulcan" can't be correct because Vulcans didn't have saucer-shaped starships:

We've seen Cargo vessels designed before Enterprise NX-01. We've also seen first warp ship designed by Cochrane. All were normal design followed from 21st century. What made Starfleet choose saucer design?

Answer 1

Purely in-universe speculation.

Warp fields are regularly represented as a squashed torus. This represents the volume of space the warp field can encompass. The filled can be stretched and spindled to wrap closer to the ship for various reasons (power usage, speed, defection, etc.) but at it's lowest complexity it is torus.

So a encompass the most amount of mass in the warp field you will shape your ships to fill the field as much as possible. That gives you a few options,

1. Making purely spherical, or elliptical ships.
2. A half circle crew section vacuum gapped from nacelles.
3. Saucer crew section vacuum gapped from nacelles.

The first is materials intensive, and does not allow for vacuum gapping the nacelles (highly energetic and hazardous to health) requiring more shielding. And the saucer shape is more structurally stable than the half circle.

So the early ships be designed to fit in a warp field as low energy and stable as possible, be as structurally stable as possible to get the the most mass and volume moved with the minimal amount of energy expenditure. From this you can estimate the class of a vessel by it's geometry.

• Slower cargo vessels have shorter travel distances between refuels would not need the efficiency of Explorer/Military vessels.
• Shorter range vessels are more wedge designed, have a less round footprint (Intrepid, Olympic)
• Combat vessels are more blocky as their armor/reinforcement can double as shielding from the nacelles. (Defiant, Nebula)
• Long range vessels are larger, but fit evenly within the torus with minimal wasted space. (Galaxy, Ambassador)

As with all design it is a balance between performance, power usage, and stability.

And we see other races following similar guidelines:

• TNG Romulan Warbirds fit the torus footprint almost perfectly and while maintaining the vacuum gap and fitting more mass into the same volume as Federation vessels. They get one of the best balances of power, range, and stability of any warship. It is one of the reasons why they are some of the most capable warships.
• Klingon vessels tend to be guns with a power-source and nacelles stuck on. They don't fill the torus footprint very well, probably trading vacuum gap for shielding, but are very flat (bird of prey arms swing horizontal for warp) allowing them to gain torus efficiencies allowing further range. Older style cruisers were less flat but they did not need the range of Federation explorer vessels as they were closer to base and do not need the efficiency. Also they have a history on not worrying too much about shielding their crew from the effects of the "Engine Pit", so vacuum gaping is preferable to added shielding.
• Ferengi vessels also fit the torus footprint running for range, but their nacelles are part of the main body with only the forward section vacuum gapped. So either more shielding or they use that section for cargo which would fit their idiom.
• Cardassian ships tend to break the torus more, but they are patrol/defense ships. They tend to be shorter range and more reliant on supply lines. On a side not there seems to be 2 almost traditions of shipbuilding, clockwise from earth they tend to be wedges with engineering and nacelles combined, while counter-clockwise they tend to be vacuum gapped.
• The Dominion - similar philosophy and limitations of Klingon but more structurally sound.

A big divergence from this is the Vulcans, but their ships seem unique as the use nacelles perpendicular to the line of motion as opposed to parallel. I don't know what benefits that would bring other then the Vulcans being able to smug that their warp fields are 90 degrees of everyone else's.

-Side note It was specified in-universe (Specifically ST: Voyager) that the Borg do not use the same warp methods as other species. I believe they used trans-warp conduits to travel. Therefore, because they use different methods than usual species, they may have no need to create designs that are as "efficient" as other ships.

Answer 2

Stealing Jeff's answer to a similar question:

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).

I doubt you are going to get a better answer than that. This Wikipedia article, and this interview with the designer of the original Enterprise show that the ship was developed by Matt Jeffries by direction from Roddenberry:

"I don’t want to see any fins or rockets, no fire," he said, "make it look like it’s got power"¹

The habitat part I felt ideally should be a ball, but it got too awkward to play with. It just didn’t look like it would get out of first gear, much less the speeds he was talking about. So it gradually got flattened. I was trying to stay away from a saucer because the UFOs or flying saucer were old hat but it did gradually turn it into a saucer.²

They designed the ship to look cool, to gain viewers, (keep in mind that the ship was originally going to be filmed the opposite side down) so any explanation as to why Starfleet chose the design is a moot point, because we already know why the ship has the design that it does.

Answer 3

It's a time loop. Cochrane saw the Enterprise-E through his telescope, therefore he decided to design the NX-01 along similar lines because he knew that it worked.

Answer 4

I think I know what you mean, in the original cannon, starships of a earlier lineage were designed to have spherical "saucer sections" In my opinion, I like to believe that Zefran chochrane saw the Enterprise E in the events of first contact and attempted a similar design, not fully understanding how the full thing worked. this would explain why the NX class ships (ENT) has a saucer shaped sections while later ships shown in TOS has spherical shapes before returning to saucer shaped ships.

Answer 5

Conjecture:

For suitability during emergency landing.

The role of a saucer is to keep the majority of the crew separate from the secondary hull, so that in emergency situations involving warp core breaches, the crew can use the primary hull as a long-term life craft.

We don't know how exactly how many saucers are capable of separating, but Constitution, Galaxy, and Sovereign classes are. Classes of ships that can't separate (Defiant-class), or are widely believed to not support separation (Intrepid-class) or separate for other reasons (Prometheus), tend to deviate from the saucer design.

Saucers might need to be able to land.

The role of life-craft can be served by say, a sphere or cube, and those designs may have benefits, but landing in such a situation might be necessary for long-term survival. Saucers from Constitution-class ships are capable of landing. As are those from Galaxy-class ships. It would stand to reason that many Starfleet saucers are capable of landing.

They fly better.

If you're going to land a saucer, you're probably hoping for a planet with an atmosphere to land on (hopefully M-class!).

A saucer shape is not the greatest shape for flying in an atmosphere but it is much better than a sphere; it's more aerodynamic and would resist tumbling, and so would require less thrust to produce a survivable landing. The neck of the Constitution-class saucer could serve some function as a poor-man's tail-fin, helping to keep the saucer pointed forward.

They're more stable on the ground.

Aside from flying, a saucer would have a relatively low center of gravity. By contrast, a sphere would require massive landing gear in order to achieve stability.

Spheres tend to.. well, roll on surfaces, and in a rough landing, like the one seen in Star Trek: Generations, the consequences to the crew would be catastrophic. A cube would beat the sphere here, but not by much, and you might end up on your side (which is in my opinion much worse than upside-down).

Answer 6

Two out of universe answers, one aesthetic, one practical.

1. The flattened front, lowered engineering area, and winged warp nacelles going up again and to the sides, makes the craft's profile approximately that of an ocean-going ship of ancient days, but with the command and control sections on the top front, like the cockpit of a modern jet aircraft. This evokes our images of exploratory ships like those of Columbus and Magellan, with the modern sensibilities of a jet plane, yet rounded rather than sharp to be less militaristic and aggressive (compare the more angular Klingon and Romulan craft).

2. A large rounded passenger section allows you to represent the insides with gradually curving hallways. Since you can't see down any given curved hallway very far, this saves money on set design since you need only build one (or at least very few) short sections thereof, using them over and over again from different angles to portray interior action. If you had long straight hallways in a rectangular ship you'd need to build a bigger set with more people in scenes looking down the hall. (Cf. why they used "transporters": it was a far cheaper special effect than shuttle landing sequences.)

Answer 7

I remember reading somewhere that table saucer shape may actually aid and be partially vital to the running of the vessel. The saucer shape could contain a gravity wheel. Creating and maintaining an 'up' for the crew onboard. The gravity wheel needs a circle or saucer in which to spin. Thus, starships with saucers may have been brought into thought. I cannot remember where I read this, or if I read it at all and I myself just came up with this nonsense. But, it makes sense to me. So I thought I'd share my thoughts.

Answer 8

I can think of three possible ways:

1. military advance
2. protect the bridge
3. crew border.

That means straight out fight hard on the Bridge. It will provide advance when it comes to all sensors UFP starship carry.

Answer 9

It may come from a section of the Tiberius Cæsar palace located in capri. Isn't it?

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Answer 10

The "Phoenix" was made from a missile shell and was a proof of concept, the other ships started the saucer for maneuverability in and out of the craft. Space has no atmosphere and other designs could lead to a slower speed in the relative pitch, roll and yaw to the ship. The saucer holds the best stance for pitch and roll and the ships would rarely need yaw control except inside atmosphere. Almost all the control is in the saucer from easy thrust placement and the shape is also perfect for crash landing from it gaining lift from decent. This gives more control allowing for the reduction of casualties from a (theoretically)smoother landing. Saucers also allow for easier escape pod access and launches from lower chances to hit the ship and easy access from flat and easy to travel halls.

Answer 11

The design for the dish came from the Andorians. The lower section came from the humans because they felt that they needed the room.