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

[thrash]

A lot depends on your tech assumptions. If you don't have force field reinforcement on your structure ("inertial damping fields") or other applied phlebotium, you should check that your design would make sense if you stood it on its engines (since that is effectively what happens when you accelerate). Don't forget that cargo (including munitions) and fuel/reaction mass will vary a lot over time, so those have to balance around the center line.

Likewise, no one ever gets required radiator area even vaguely correct, because it looks terrible and would be lethally fragile in a fight. (Discovery, from 2001, was as long and skinny as it was because it was supposed to have realistic radiator fins all along its length. It looked dumb, however, so they were deleted.)

Finally, remember: form follows function. Freighters prioritize cargo space; warships emphasize weapon systems. Neither one puts a premium on comfortable quarters for the crew. Any ship with a balance of all three is questionable, unless it really is a rich person's privately owned, purpose-built yacht-and-pirate-hunter. Choose the role for each class and optimize for it.

[Michael Thayne]

Originally Posted by thrash

Likewise, no one ever gets required radiator area even vaguely correct, because it looks terrible and would be lethally fragile in a fight. (Discovery, from 2001, was as long and skinny as it was because it was supposed to have realistic radiator fins all along its length. It looked dumb, however, so they were deleted.)

The video game Children of a Dead Earth claims to be rigorously realistic in almost all respects and the ships look pretty cool IMHO. Incidentally, the warships in that game tend to have pointy noses even though they're not intended to fly in atmosphere. Rather, the game is trying to model the benefits of using sloped armor.

[Anthony]

Originally Posted by Michael Thayne

The video game Children of a Dead Earth claims to be rigorously realistic in almost all respects and the ships look pretty cool IMHO. Incidentally, the warships in that game tend to have pointy noses even though they're not intended to fly in atmosphere. Rather, the game is trying to model the benefits of using sloped armor.

Sloped armor won't be terribly relevant against beam weapons, or against kinetics at space combat speed (it basically increases defense by the same amount as it increases weight).

[Michael Thayne]

Originally Posted by Anthony

Sloped armor won't be terribly relevant against beam weapons, or against kinetics at space combat speed (it basically increases defense by the same amount as it increases weight).

A lot of ships in CoaDE are built for low-velocity intercepts. When I used to play the game, I tended to go for high-velocity intercepts myself, but I could never tell if this was a good tactic or if I had just found a blindspot in the AI.

[Fred Brackin]

Originally Posted by Michael Thayne

A lot of ships in CoaDE are built for low-velocity intercepts. When I used to play the game, I tended to go for high-velocity intercepts myself, but I could never tell if this was a good tactic or if I had just found a blindspot in the AI.

If you want intercepts and hard kills rather than rendevous and disables high velocity is great.

Armor on the other hand is pretty dubious. Even just abating the effect of high velocity KE weapons, ionizing beam weapons and nukes would be incredibly hard. Only a deeply spaced sort of honeycomb with many layers would be worthwhile at all (and they'd be ablative). Solid slabs of armor consisting of any sort of normal matter would just become a medium to conduct the blast wave or a source of secondary radiation.

Until there is a enough of a space-based economy to build big ships size is sharply limited. Just a SM+8 ship in Spaceships is a 1000 tons and that's 50 loads for the space shuttle (or similar vehicle) or 10 loads for the biggest heavy lift vehicle I think is realistic for Earth-launch.

A million tons is of course 1000x as many lunches required. If you've got enough space-based industry to handle that Earth-like planets are used as nature preserves or at perhaps luxury housing.

[Michael Thayne]

Originally Posted by Fred Brackin

Armor on the other hand is pretty dubious. Even just abating the effect of high velocity KE weapons, ionizing beam weapons and nukes would be incredibly hard. Only a deeply spaced sort of honeycomb with many layers would be worthwhile at all (and they'd be ablative). Solid slabs of armor consisting of any sort of normal matter would just become a medium to conduct the blast wave or a source of secondary radiation.

CoaDE is extremely conservative in tech assumptions—it doesn't even have everything GURPS calls TL9. So no x-ray lasers or charged particle beams, and even UV lasers are usually more trouble than they're worth. My memories of playing the game are that armor tended to be effective against (non-ionizing) lasers, conventional guns, and electromagnetic guns. It was not a remotely reliable defense against missiles, though rare occasions it might, say, save your butt against a small nuke detonated some distance from your ship. Though I don't think CoaDE tried to model transmutation due to neutron flux; nukes were treated purely as a source of electromagnetic radiation that would melt your ship at close range.

[Fred Brackin]

Originally Posted by Michael Thayne

C. Though I don't think CoaDE tried to model transmutation due to neutron flux; n

No one should. A high energy neutron from a nuclear explosion carries a lot of KE relative to an atomic nucleus. Any nucleus it hits will go flying and break the molecular bonds of a significant number of other nuclei that were in its' way.

When you're being hit by large numbers of those neutrons they should be treated as ionizing radiation rather than a source of heat. Individual atoms transformed by neutron capture are just anomalies in the ion cloud.

[Ulzgoroth]

Originally Posted by Michael Thayne

The video game Children of a Dead Earth claims to be rigorously realistic in almost all respects and the ships look pretty cool IMHO. Incidentally, the warships in that game tend to have pointy noses even though they're not intended to fly in atmosphere. Rather, the game is trying to model the benefits of using sloped armor.

It's been a few years since I dipped into it but I don't think the benefits of sloping as such were very significant. But using a tapering nose to allow more frontal weapon mountings so you could attack head-on rather than needing to swing broadside and expose a much larger aspect was quite useful. Also it gave you thicker effective front armor without having to mess with the controls (and possible penalties) for adding armor layers that only covered a portion of the ship.

Of course, that's influenced by the game leaning to sustained gun engagements by preference, but you certainly could build a missile carrier that used efficient atomic rockets to drop missiles onto high-speed intercepts where they'd proceed to punch through anything in their path. I did that at one point, pretty sure it made a mockery of all the big battleships. (It might have been vulnerable to flares though, since the game made missile guidance highly vulnerable to decoys.)