Rocket materials

[SSTO Crasher]

I had an idea today, in ksp2 we should have parts with a toggle to set the material the part is made of, and each has benefits and drawbacks 

Edited December 7, 2022 by SSTO Crasher

[GoldForest]

Mmmm, I say leave that up to the modders to do. That seems like an advanced feature that some of the newer players will have trouble with. 

Like, only people who know rockets will know what a 'balloon' tanks vs a regular tank is. Furthermore, you got several different materials. Steel, aluminum, carbon composites, insulated, non-insulated, etc. 

[Domonian]

I love this idea! I've had a similar thought before, so I'll dump my thoughts here. 

I think different materials for different parts could fit quite well into the stock game, and it doesn't have to be difficult or very specific. Maybe the player needs high heat resistance, so they opt for thicker heat shielding (or a better material) that increases heat resistance, but also increases cost and weight. Maybe they can't increase the weight due to other limitations, so they use a more advanced material that has similar heat resistance, the same weight as the standard material, but is much more expensive (and maybe less resistant to radiation, physical impacts, or other factors). Sliding bars may be too complicated, but having a select few materials/options for parts could give the player more control over how they choose to design their vehicle. Maybe you can afford lightweight but still strong structural pieces for your interstellar craft, or maybe you can't and you need to opt for the cheaper, yet heavier version. This could be communicated to the player via a set of bars to show modified stats, with green on the positive sign and red on the negative sign (with descriptive words at each end; more weight =/= positive and that should be specified). 

I don't know if this feature could effectively be extended to parts such as engines, but for "body parts" it is definitely something I'm interested in. Late game could feature "super alloys," that have all the benefits but are incredibly expensive and time consuming to produce, or use resources that are incredibly hard to get a hold of. 

[机械主教71号]

The more expensive, the better.

[K^2]

11 minutes ago, 机械主教71号 said:

The more expensive, the better.

At the first glance, it might look like the netherite fuel tanks provide the same amount of storage as the diamond fuel tanks, but they're lighter, which gives your rocket a significant advantage in I_SP overall.

[机械主教71号]

 

6 hours ago, K^2 said:

At the first glance, it might look like the netherite fuel tanks provide the same amount of storage as the diamond fuel tanks, but they're lighter, which gives your rocket a significant advantage in I_SP overall.

I mean, the meterial which provides larger m0/mk, is usually more expensive, for example, aluminum alloy vs. stainless steel. Not  because the aluminum alloy is lighter, but the aluminum alloy has higher specific strength and specific stiffness.

Edited December 9, 2022 by 机械主教71号

[Rutabaga22]

Maybe it could change the look of the tanks. A foam tank would have External tank/SLS-like texture, while karbon fiber tanks would look like early Staship designs. You could even extend out materials to capsules by giving them thermal advantages. Maybe you could add thermal blankets or heat tiling and they would make your capsule look different.

[SSTO Crasher]

I think that we should at least have a selection in the right click menu with things like aluminum and titanium

[SciMan]

I can think of 4 (maybe 5) categories of options to choose from:

Base Material, Construction method, Insulation type, and Surface Finish.
The one that I'm thinking might be optional is "Bulkhead type", and that category would only show up if you selected more than one resource to go in the tank (options would be something like "Common Bulkhead" and "Intertank", but I can easily see this whole category becoming a sub-category to the Construction Method category).

Base Material is the closest to what OP wants. You'd be able to choose between things like Stainless Steel, Aluminum alloy, Al-Li alloy, Fiberglass composite (IDK why no rocket ever used that as a fuel tank material, it's stronger than aluminum mass-for-mass, but not quite as strong as carbon fiber), Carbon fiber composite, Titanium alloys, maybe even Nickel Super-Alloys (like Inconel) if you need to contain hot high pressure and potentially oxidizing gases in a tank rather than a rocket engine for some unknown reason.

Construction method is where you'd choose between options like "Sheet metal tank with internal ribs (the one you'd start off with)", "Isogrid (hex/triangle grid, strong and light)", "Orthogrid" (same as isogrid, but with squares instead of hex/triangle), "COPV" (for low temperature high pressure gases or RCS propellants, only shows up if you selected a composite base material), "Bladder tank" (RCS propellants and monopropellants only (if there's a difference)), "Balloon tank" (probably only available for stainless steel), and maybe "SRB Casing" (if we get modular (not procedural) SRB's), as well as "Structural tube", which would be a heavier option that can't hold any resources but is hollow and has a higher impact tolerance (material permitting, it would have a higher heat tolerance as well).

Insulation type would be things like "Foam (Pre-cast)" (starter cryogenic tank insulation, foam insulation panels cast to the correct shape before being applied to the tank in tiles and retained with fasteners), "SOFI" (spray on foam insulation, higher tech, slightly lighter because it's just stuck on there rather than needing fasteners, and more insulating launch vehicle cryogenic tank insulation based on that used by Shuttle/SLS), "Multi-Layer-Insulation" (the gold foil stuff you see on satellites, better than foam of any kind in vacuum, but useless if there's a significant atmosphere), and things of that nature.

Surface finish would have options like "Bare" (lowest mass option, might have penalties for insulation or tank durability), "Painted" (required if you want to put fancy designs on the side of the tank, and maybe useful to mitigate exposure to the elements), "TUFROC" (ablative paint that increases the maximum skin temperature of the part, at least until it's all burned away), and maybe even "TPS Tile" (basically shuttle heat shield tiles, with options for White (lower temperature) and Black (higher temperature) tiles, the tile option would be a non-ablative heat shield option usually used for spaceplanes if they have a base material incompatible with high internal temperatures (like most aluminum alloys).
Surface Finish is how you'd apply heat shielding to spaceplane parts without them having to create dedicated "airplane only" parts for the game that would be ignored by most people.

IMO this would greatly deepen the game by allowing the player to make many more design trade-offs.
For instance, do you want to make your spaceplane with a Titanium internal skeleton so that you can save money on the heat shield system by only using TUFROC, or do you want to spend more money on the heat shield system by covering it in TPS Tile and saving weight by switching to an Aluminum Alloy internal structure (like the Shuttle did)?
Do you want to use Carbon Composite, Internally Braced, Common Bulkhead tanks with SOFI and Bare surface for the upper stage of your Hydrolox launch vehicle, or do you want to build a Centaur-like stage that uses Stainless Steel Balloon tanks with a Common Bulkhead and SOFI insulation with Bare surface
There are a lot of possibilities here, and that should mean that there are enough options to allow someone who knows what they're doing to pick the options that optimize the fuel tank to whatever task they have in mind for it.
As for that "A person that knows what they're doing" disclaimer, don't let that make you think the idea isn't bad, the game could easily have a little tool tip that pops up when you hover over any of the options in any of the categories that has a short text blurb that describes why this option is different from the other ones, as well as out-and-out saying what each option is best suited for.

[K^2]

2 hours ago, SciMan said:

Surface finish

I know this isn't where OP was going with it, but the materials make me immediately think of rendering materials, and given the various painting options we're getting, I would absolutely love it if we can not only paint the color, but also various PBR properties, like roughness and metalness, maybe even some subtle emissives, so that we can really give our space-ships that sci-fi look if we want it, or just the opposite, go for worn and rusted for something a bit more Kerbal. This would be particularly great with custom decals. Want a spot of rust on a shiny chrome part? Set metalness to the max and roughness very low for the chrome look, then slap a rust decal where you want it, with low metalness, high roughness, and maybe even a bit of a normal map to make it extra.

That should be well within the capabilities of the engine and if they're already doing all the work for paint customization anyways, that's basically one extra layer that paint and decals can affect. Bonus points for virtual texture on the craft, so that the decal count doesn't affect performance. (Though, that would be a lot of work if something in the game isn't using virtual textures with decals already.)

[Drakenred65]

fiberglass was used in Apollo and Skylab as insulation, and Russia/former USSR used formed fiberglass structures in some projects or prototypes in the mid 60s to early 70s. 

[SciMan]

I was more referring to glass-fiber resin composite, not fiberglass insulation. Same material, but used in a structural context not a thermal context.

[MK2-DroneCore]

Great idea! As a CDE player, I really like this "Specific Mission Tanks" option. But mind that some materials are not able to handle some fuel. For example, You can't use Steel to bulid a H2tank, common Steel will become weaker in a low temperature enviroment espacily with Lqd Hydrogen.

Maybe we can add some Carbon-ceramics

[Drakenred65]

6 hours ago, SciMan said:

6 hours ago, SciMan said:

I was more referring to glass-fiber resin composite, not fiberglass insulation. Same material, but used in a structural context not a thermal context.

 

The solid resin Formed fiberglass was what the Russians tested for components. Not sure why it never went anywhere, but assume Politics.

[K^2]

1 hour ago, [email protected] said:

The solid resin Formed fiberglass was what the Russians tested for components. Not sure why it never went anywhere, but assume Politics.

The mechanical properties of fiberglass composites are very temperature sensitive. It's the main reason why the use cases for that material in aerospace industry are limited.