Spaceship Design: What makes sense, and what's nonsense?

[dcarson]

Originally Posted by Rupert

The early Skylarks in E.E. 'Doc' Smith's Skylark series of novels were spherical for this reason, complete with centre-mounted drive.

And it let you have big enough aiming gear to let you target a ship at hundreds of lightyears. Smith thought big.

[Anthony]

Originally Posted by dcarson

And it let you have big enough aiming gear to let you target a ship at hundreds of lightyears. Smith thought big.

And that was in a middle book. Skylark series I think takes the prize for fastest power escalation in any SF series I've seen.

[Rupert]

That's why I said 'early'. Skylark Six was spherical for an entirely different reason, and had her size determined by the requirement of her sensor and mapping system (which had to be big enough to resolve and map the entire universe).

[Opellulo]

As many have already pointed out you have to decide how much "Space Magic" (FTL, artifical gravity, etc...) you want to use but, even after considering this, you have to work into account an often overlook element: logistics.

"Standard" space ships makes no sense: too big to be built and launched from a planet and too resource expensive to be built in orbit. Anything that complex requires a logistic network that's going to be much more important than the space ships there produced.

So maybe a more sound approach would be to design the space infrastructure and then populate it with the necessary spacecrafts to operate it: unmanned mining drones, orbital space stations that works as switch from space travel to atmospheric descent, surface launch pad that works as heavy traffic cargo launchers, this kind of things.

An aircraft doesn't land on your backyard and for the same reason a craft able to deep space travel should not be able to land anywhere on the surface of every planet.

[Witchking]

Originally Posted by Opellulo

As many have already pointed out you have to decide how much "Space Magic" (FTL, artifical gravity, etc...) you want to use but, even after considering this, you have to work into account an often overlook element: logistics.

"Standard" space ships makes no sense: too big to be built and launched from a planet and too resource expensive to be built in orbit. Anything that complex requires a logistic network that's going to be much more important than the space ships there produced.

So maybe a more sound approach would be to design the space infrastructure and then populate it with the necessary spacecrafts to operate it: unmanned mining drones, orbital space stations that works as switch from space travel to atmospheric descent, surface launch pad that works as heavy traffic cargo launchers, this kind of things.

An aircraft doesn't land on your backyard and for the same reason a craft able to deep space travel should not be able to land anywhere on the surface of every planet.

Well for getting from ground to orbit two old sci-fi concepts come to mind. Both are plausible if on the edges of reality.

1. Space Elevator

2. Launch Catapults (electro-mag variety).

If a planet has either operable the cost per pound to orbit drops quite a bit. Since most of the cost is up front the longer you operate it the cheaper the per pound cost becomes.

[doctorevilbrain]

The best source of information is the Atomic Rockets website.

[Pursuivant]

The GURPS Spaceships series is a good starting point for what's realistic, what's theoretically possible given the current state of physics, and what's science-fantasy.

Any system of TL8 or lower is "realistic" - could be built or has been built with early 21st c. or earlier technology.

Any system of TL9+ is "possible with sufficiently advanced engineering and physics."

Any system with a ^ next to it violates the laws of physics as we know them.

The volume sizes for a given ship and relative size of components can also be used as a basis for making spacecraft drawings.

[Fred Brackin]

Originally Posted by Pursuivant

T
Any system of TL8 or lower is "realistic" - could be built or has been built with early 21st c. or earlier technology.

Any system of TL9+ is "possible with sufficiently advanced engineering and physics."

Any system with a ^ next to it violates the laws of physics as we know them.

The volume sizes for a given ship and relative size of components can also be used as a basis for making spacecraft drawings.

Some systems of TL8 and 9 have had their efficincy exaggerated to reflect that they were once thought to be viable and maintain their use in retrotech designs.

Also, the presence of the ^ cancels out any assignment to "realistic" TLs. Rotary Reactionless at TL7^ is an example.

Finally, Spaceships _mass_ numbers are (usually) hard within it's limits of resolution (scales of 1/3/10). "Volume" or even just "length" are vague suggestions.

[Lovewyrm]

Spaceships could be built in orbit using some sort of magical epoxy like substance that doesn't work in an oxygenated environment and offers superb strength and can be extruded into shapes from logistics friendly barrels/tanks, doing away with the need to shoot bulky shapes into space.
Space/mass wise it would be like shaving foam. It expands, is porous but hardy and gets sealed with another substance so it's not just swiss cheese)

That way only the first orbital factories would have to be 'hard mode' assembled.

Maybe this substance won't be the final chassis, but maybe it would be a 'good enough' a scaffold to fly from home planet to local star system megafactory.

Just good enough to withstand normal travel. Combat ships need armor bolted on there, or something.

[Johnny1A.2]

Originally Posted by FF_Ninja

I'm going to be spending some time in Inkscape and GIMP over the next few days working on some custom top-down spaceship layouts for use in a campaign later. In preparation for this, I started looking today for reference models (starting with my old stomping grounds, CGSociety).

It then ocurred to me that I'm highly influenced by sensational, flashy, exotic designs - and I don't have a clue what's more functional and realistic versus what might be highly improbably or unlikely a design feature to be incorporated.

To give you a point of reference: I don't see any functional or physical inconsistencies or design flaws with the typical Star Trek and Star Wars faire.

My plan is to design an entire hierarchy of new ships for futuristic Earth, starting from the earliest space-fairing vessels, gradually incorporating FTL into the design (haven't settled on what FTL actually looks like in this setting), and building on that form factor over time.

I would very much prefer to approach my designs with a practical understanding of what "would" and "wouldn't" make sense, rather than throwing elements together in an arbitrary fashion.

For those of you who consider yourselves more of an authority on "space-y" things, I would appreciate any insight into what would make sense in terms of spaceship design and form, and I appreciate any commentary on examples in media that stand out in one way or another.

Thank you all very kindly.

As others have pointed out repeatedly on-thread, what 'makes sense' depends on what the technology assumptions are, and also on the purpose of the ships and how rich the society is.

If you're looking for basics:

1. If the ship is rocket-propelled, 'down' is the direction toward the engine. The ship will be laid out internally more like a skyscraper than seaship. Except that 'down' is only that way while the rocket is firing. Then, unless you have artificial gravity tech, the interior is either weightless or you're spinning it, in which case 'down' is toward the outer wall.

2. If the ship is rocket propelled, then the designers will try to make it as light as humanly possible. Literally every milligram of mass they can shave off helps.

3. You mention media examples, and the problem is that in visual media there just aren't many. The reason is that a spaceship built with technology we can envision right now, under our current understanding of physics, looks fragile and clumsy and actually is going to tend to be fragile. Battle means that either you get hit and are destroyed, or they missed and you're fine. Not much in between, and very little margin to maneuver or do much else except hope your weapon gets him before he gets you, and the battle will be at distances where your unaided eyes won't matter.

Which is why Star Trek is perversely in some ways more believable than the Expanse. At first glance the latter show uses tech more grounded in the physics we think is real, while ST uses a lot of what we think is impossible magical tech (but keep in mind that nuclear bombs, radios, X-ray machines, spectrographs, etc. are impossible magical tech, too, by the physics of 1822).

But the problem is that given the more 'realistic' tech, it's highly improbable that the situations described in The Expanse will come about in the first place. Whereas once you posit the superscience, some of the Trek setting suddenly becomes plausible.

What makes for a believable space ship depends on the setting and the intentions of the creator.