Spaceship design - a hypothetical excercise

[bobdude11]

... the images I've seen from Alcubierre's work shows something that looks like an elongated football with a ring around it, and I imagine the force of gravity would be oriented in the direction of travel; IOW, you'd be flying feet-first.

Thank you for the detailed explanation - admittedly, I have only a VERY basic understanding of the math, it still makes sense how you describe it! Also to your note, in the series Enterprise, the Vulcan ships are elongated with a warp ring instead of two nacelles. Perhaps a nod to Alcubierre?

Be aware I'm just a moderately enthusiastic code monkey, not an expert in theoretical physics, or aerospace engineering, or much of anything else, really.  I got through one semester of Differential Equations with a D for Done, so I'm going off of a layman's understanding of all of this.  Don't take any of this as more than poorly informed opinion.  I think I'm right in the large, but I couldn't math my way out of a paper bag so I wouldn't be able to back any of it up. 

You still have more math experience than I do ... in the dictionary next to neophyte, you will find my picture.

[JayUtah]

In the design of hypothetical spacecraft such as for fictional purposes, real engineering is often your worst enemy. Hence an expert knowledge of physics is not always an advantage.

In making Alien, first Ron Cobb and then Chris Foss was employed to design the alien ship. Both ended up making ships that were visually exciting, but spent too much effort trying to express how they worked. H.R. Giger gave us a ship that looked decidedly non-human and didn't give rat's ass how it might have worked. Neither Cobb nor Foss had an engineering background. But even as artists they believed that form followed function, and therefore some of the function had to be worked out even if it eventually boiled down to an appeal to magic. Cobb's design for the Nostromo is clearly a human design and alludes to a human vernacular of function. The flight deck is stuff scavenged from airplane boneyards. Giger's design for the alien technology is pure imagination, and that's why it works for the story.

I've corresponded many times with Rick Sternbach, who is an avid Apollo historian in addition to being one of the technical inventors of Star Trek. And his protege John Eaves is a good friend of mine. He designed the Enterprise NCC-1701E, but he started out as a model maker and a vintage airplane fan. Coincidentally he was heavily involved in restoring the Nostromo hero model. He and I have had many discussions on how to make fictional spaceships and it always comes down to deciding where to draw the line between physics and fiction. Every attempt to describe how a Starfleet engine is supposed to work is going to eventually arrive at a request to suspend disbelief in physics as we presently understand it. That doesn't mean it can't be a fun framework for discussing how real physics works (and therefore how the Enterprise doesn't), and to speculate on what might have to change in our understanding of the physical world in order to accommodate one. Maybe once you've had a heated debate over whether the Millennium Falcon could outrun the Enterprise or whether a photon torpedo could take out a star destroyer, you start to see where that speculation ceases to help. (I also got to meet Colin Cantwell at a convention—loved that guy!)

Rick Sternbach and his colleagues produce the Starfleet Technical Manual not because they finally had all the physics worked out, but because they were tired of writers bringing different ideas to the table about how the technology worked and trying to make plot points out of them. Back in the 1960s all you needed were magic crystals to make the ship go. You didn't need to know how the ship worked any more than you needed to know how to sail in order to appreciate Horatio Hornblower. And it's not important how John Carter got to Mars as much as it is what he did when he got there. But for a more educated and interested audience, it became necessary to standardize some of the speculation in order to preserve continuity. In the end, this serves good storytelling because it reduces the machina from which an unsatisfying deus can be extracted.

The more you know about physics, the farther into the realm of "physics you don't know" you have to push that line between fact and fiction in order to find intellectual satisfaction. But as long as you're talking about fictional spacecraft whose primary job is to support and enable an otherwise farfetched theatrical narrative, that line will always be out there. Therefore it's pointless to disclaim that one doesn't know enough about physics in order to determine whether a ship will work. No matter how elaborate the scenery, you'll always be able to look behind it and see plywood and lumber, so it's useless lamenting that you aren't as adept at looking behind the scenery as someone else might be. If thinking about how starships might work is a fun activity for you, then frolic in it without regret or excuse. It's meant to be fun for everyone no matter your background.

[Peter B]

I'm an avid gamer, having played both table top games and role-playing games over the decades.

Back in the late 1970s the science fiction RPG "Traveller" appeared, and for a decade or two it was really popular. It soon expanded into ship design, and then fleet design. The book "High Guard" provided rules for designing warships, and like some of my friends I wasted many weekends designing all sorts of ships in the (likely illusory) search for the ideal design.

The book's writers had clearly put a lot of thought into the rules (remembering this was before PCs and spreadsheets would simplify the design job). One of the early decisions you needed to make when designing a ship was what sort of hull shape you wanted. That decision affected (a) what percentage of the ships weapons could fire at a single target, (b) the cost of the hull, and (c) whether it could enter an atmosphere (i) always, (ii) never or (iii) sometimes, depending on the atmosphere.

Hull types included:

1. Needle (like a Saturn V);
2. Cone (sort of like the N1);
3. Wedge (like a Star Wars Star Destroyer - the similarity between them and early Traveller artwork is intriguing);
4. Flattened sphere (like a traditional UFO);
5. Sphere (like the SW Death Star);
6. Irregular structure (like the Battlestar Galactica);
7. Dispersed structure (like the ISS);
8. Planetoid (that is, built into an asteroid); and
9. Buffered planetoid (again, built into an asteroid, but leaving more of the asteroid).

When combined with the game's lore on how you travelled ('jumped') between star systems, the game often pushed you into very specific and interesting design choices. For example, if you wanted to maximise your ship's jump range you needed to allocate massive amounts of volume in the ship to fuel, which in turn encouraged the idea of massive jump ships which carried several more modestly sized warships with no jump capability as "battle riders".

= = = =

Then, in the 1990s came the tabletop miniatures game "Full Thrust". Again, in FT you can design your own ships, with a variety of weapons, armour levels and speeds. However, the game also provides preset designs for different fleets, along with the miniatures for those fleets.

The designs of these miniatures are visually distinct, so you can tell at a glance which fleet a ship belongs to. However the appearance of all the ships doesn't bother to take into account the weapons mounted on them; identically-armed ships from different fleets will look different from each other, while differently-armed ships from the same fleet will look similar.

In this case, the purpose is to give the players visually interesting objects (the ship models) to expend their painting skills on, on order to add an aesthetic angle to the game.