Updated description:
• Fixed Boron Filament changelog.
• Added third source to Diamond's melting point and expanded its notes section.
• Added link to (RSM) materials spreadsheet.

The experiment is done in a non-oxidizing environment and at pressures not exceeding 267 μPa. Those do not seem to be conditions found in lasers ("The arc lamp envelope will rupture from the stress" error seems to suggest that the arc lamp envelope has to withstand the gas internal pressure), and surely are not conditions found in a rocket engine (as I can not prevent diamond from being used there, it needs to have a safe use temperature that would make it survive in those conditions too).

The paper says that oxidizing agents cause oxidation of diamond at temperatures as low as 923 K (in the right conditions; usually 1273 K or higher), and current diamond melting point is 1235 K (the lowest I can go without breaking stock lasers).

Unless I misinterpreted something, I think it's safer to leave diamond melting point as is.

Thanks for the link, Zuthal. AtomHeartDragon has already provided it, but I still haven't implemented it. It's on my todo list though.

For the diamond issue, this article says [royalsocietypublishing.org] that heating at 1500 °C for 45 min under a vacuum yields barely any graphitisation and only on an exceptionally thin specimen, with the rate increasing rapidly up to full graphitisation in 5 to 10 minutes at 1900 °C.

So, I think it would be justified to set the "melting point" for diamond up to possibly as high as 1700 K (still 73K below the temperature at which only a very thin specimen showed any detectable graphitisation).

Added spreadsheet with all material properties. Link in the description.

Mod, description and change notes updated. If you've ever used this mod before this update, every time you booted the game while subscribed to this mod a new crash log was generated in %AppData%\Roaming\CDE\Crashes. If there are no crash logs you're interested in keeping, you can delete that folder. Sorry for the inconvenience.

Mod, description and change notes updated

It seems that material properties are irrelevant for arc lamp vapors, so this means that I don't have to make separate liquid and vapor states for the same material.

@AtomHeartDragon
Unfortunately I don't have much free time this period, but hopefully I should be able to fix the tracers relatively soon.
I don't understand what "blocks" means in the last sub-mod you're proposing. Materials cost and properties fixes mods woudln't be compatible with each other because of the diamond though, so I would have to make a mod for each combination.
The fact that people can select Tungsten Rhenium as a rocket engine material does not change the fact that they can select it as a thermocouple material...

@WarDaft
Thanks for the paper!

Didn't mean to leave a reply for so long, but, I do finally have a source for a supposedly common material for at least some kinds of rocket engines: Disilicide coated niobium alloys.

Source is:
https://arc.aiaa.org/doi/abs/10.2514/3.23967?journalCode=jpp#:~:text=engine%20combustion%20chamber%20requires%20the,of%20the%20propellant%20combustion%20temperature

And contains proposals for other materials.

One outcome I don't have a source yet for is simply considering the engine disposable and having part of the chamber literally burn away during normal operation.

Also, I don't think Tungsten-Rhenium change is good, since it breaks one of the primary applications of the alloy - rocket engine won't be running that long.

@Echo
This breaks a bunch of tracers (they are based on emission spectra).
Additionaly stuff like vaporized sodium or mercury are legitimate lamp discharge media (you probably see streets illuminated by them every night), so bl;ocking them is BS.

Also suggesting splitting this up to make it more modular. I'd go with:
* crewium cost
* reduction (or increase) of outrageous material costs
* property fixes (with replacers)
* blocks (with replacers, stressing not breaking anything it isn't supposed to break)

> As for decomposing to graphite, it has an estimated activation energy of between 367 and 583 kg/mol

At what pressure and temperature? If the estimate is not valid at 0 Pa and ~1175 K, then it's not useful for applications in COADE. Also, the conversion rate implies that there is a point, a percentage of diamond that has turned into graphite, that would structurally weaken the system, that is lower than the total conversion of diamond into graphite.

> in the presence of an oxidizer, it sublimates at much lower temperatures. You've already taken into account what I'm saying, but only for Diamond.

Sublimation temperature in the presence of an oxidizer wasn't mentioned in the paper I referenced. I didn't take that into account when lowering diamond melting point, but the temperature at a pressure of 0 Pa for which diamond is more stable than graphite. Unfortunately, such a temperature does not exist because at 0 Pa graphite is always more stable than diamond, so set diamond melting point to the minimum temperature that does not break stock lasers.

> As far as chamber materials, you're talking about having a high temperature oxidizer beside an oxidizable compound. You don't really need a source to know that won't work

I meant to ask if you know what materials are used in combustion chambers irl, with sources.

> there's also to my knowledge nothing you can do to prevent that from working in the game.

I can confirm that unfortunately there is no way to simulate chemical incompatibilities in the moddable .txt files.

> Diamond has a stupidly high safe working temperature *in a vacuum* which is why it's so high in the game.

Like with all materials, only diamond melting point is defined in the game files. Like with all materials, diamond safe use temperature is melting point times 19/20. I don't know where/how QSwitched found diamond melting point, but my educated guess is that it's at 1 atm, in line with pretty much all other materials.

As for decomposing to graphite, it has an estimated activation energy of between 367 and 583 kg/mol (If you consider StackOverflow a source, https://chemistry.stackexchange.com/questions/34193/are-diamonds-really-forever) , while the infamously high vapourization energy of water is only 40 kj/mol, and that's with with 50% heavier mols for water. I'd have to find the right formula for calculating the exact rate, and tables for high energy specific heat, because temperature wise, that's an activation energy of *over* 50 thousand kelvin(!) for diamond using the STP specific heat.

As far as chamber materials, you're talking about having a high temperature oxidizer beside an oxidizable compound. You don't really need a source to know that won't work, but there's also to my knowledge nothing you can do to prevent that from working in the game.

That is to say, the "safe working temperature" depends on the chemical environment. Diamond has a stupidly high safe working temperature *in a vacuum* which is why it's so high in the game. But, in the presence of an oxidizer, it sublimates at much lower temperatures. You've already taken into account what I'm saying, but only for Diamond.

As for construction cost... fair point. I was going to say that the supposed 3d fabbing should neutralize it, but UHMWPE should still be cheaper than diamond with that capability.

> Why did you make diamond more expensive?

> we literally cannot build things bigger than a piece of gravel out of solid diamond right now.

You answered yourself there ;)

Do you happen to have a source regarding chamber materials?

Why did you make diamond more expensive? Synthetic diamond already isn't that expensive and industrial diamond even less so (industrial diamond can be as cheap as $1500/kilo).

As far as chamber materials, NASA never used it because we literally cannot build things bigger than a piece of gravel out of solid diamond right now.

That said, carbon's reactions with all oxidisers should rule out ANYTHING primarily carbon as a chamber material. Really, there are a *lot* of materials that would just start to burn before they melt or even weaken when in the presence of high temperature oxidiser.

> If I release a pack of ships or components on the workshop that are intended to be used with this mod, is there a tag or something I should use?

After you upload a module or ship that uses any mod, it's always a good practice to add that other mod / those other mods to the required items of your mod. You can find "Add/Remove Required Items" in the right of the mod's description, in a panel visible only to the mod's author(s). Click that, change the tab to "Subscribed Items", and add the mod(s) you used to make your own mod.

> I'd give you another award, but Steam won't let me

Thank you, knowing that someone uses this mod is reward enough for me :)

> it's no longer the hands-down ideal rocket chamber material!

It never was, otherwise NASA would have used it ;)
In-game I use reinforced carbon-carbon or zirconium carbide, but I don't know if they are actually used irl or not. I don't think this source suffices:
https://doi.org/10.1016/B978-012341834-0/50004-0 , p. 95

> use ethane for coolant anywhere sodium isn't doing it for me.

Ethane decomposes at high temperatures, so it might not even be useful in RTGs:
https://doi.org/10.1016/B978-0-444-64000-0.00002-0 , p. 44;
https://doi.org/10.1016/j.fuel.2020.117409

Sodium could be used as a coolant, but either at not very-high temperatures or in absence of carbon (fuel moderator in the inner loop, radiator in the outer loop and turbopumps in both loops):
https://www.researchgate.net/publication/228616619_Carbon-Carbon-Composite_Salt-Cooled_Electric_Space_Reactors , p. 6 (link provided by SevenOfCarina)

That's very useful info, thank you! I largely stopped using diamond with your mod (it's no longer the hands-down ideal rocket chamber material!), but I do happen to still use ethane for coolant anywhere sodium isn't doing it for me.

If I release a pack of ships or components on the workshop that are intended to be used with this mod, is there a tag or something I should use? Or maybe I should put it all in a collection and a link to this mod in that collection?

PS) Normally I'm opposed to "realism for realism sake" in games since it detracts from gameplay, but honestly this improves CDE if for no other reason than making diamond less OP. In CDE, excessive realism fits. I'd give you another award, but Steam won't let me, lol.

It depends on the material and for what you are using it for in a module. Materials that had their elements count, cost, refractive index and roughness coefficient changed will work fine in vanilla. If the melting point was reduced, then the module will work fine in vanilla. I'm not too sure about modules made with diamond or ethane, there might be cases in which they break.

Do you happen to know if designs made with this mod will function in vanilla?

Thank you. Human cost changes the Crew Module cost, is determined only by the crew capacity and is a cost per kg. Each human weighs ~58.7 kg, so that is 1.21 Mc per person.

Very nice mod. Thank you guys for taking the time to work on it.

Just wondering what does "human" cost does. Does it increase the ship's cost with crew size? Is it actually a cost per kilo or per unit?

Nerfing diamond and lowering melting points makes things much harder! Totally appropriate though.

SevenOfCarina, AtomHeartDragon and people from the forums are the masterminds, I mostly put the mod together. SevenOfCarina even shared some papers that touch on material incompatibilities in reactors and attached radiator modules, and reactor fuel burnup, but unfortunately I have no way to mod her findings in the game.

The designs should be fixed. I used your fixes for 2.90 km/s Nitrogen Nuclear Thermal Rocket and 234 kW Thermoelectric Fission Reactor. For the 1.04 MW Thermoelectric Fission Reactor, reducing the moderator mass causes the module to have a higher radiation hazard, which might result in broken user designs. So I changed the Control Rod to Titanium Diboride as per your suggestion, and I changed its mass to 33.1 kg.

I actually used Hafnium Diboride in those designs, which is not a stock material. Your game changed it to Aluminum because you don't have Hafnium Diboride as a modded material. When I made those designs fixes three months ago, I had released only one material mod in the forums which has both realistic replacements for stock materials and new materials. I'm splitting the two mods for the Steam release, and I forgot to check those old modules replacements since they worked flawlessly for me all this time.

@AtomHeartDragon It shouldn't be hard to fix.

@Arrow Thanks for the feedback, after a very quick investigation I found the problem is within the modified modules. It'll be fixed tomorrow. Thanks for sharing how you fixed the modules, it's been of great help. Sorry for the inconvenience.

And with that out of the way, I'd also like to say thank you for taking the time to research and put together this pack. I'm really enjoying study the material changes to tweak some of my module designs. It's really keeping this game interesting.

I get some errors with a few of the replaced modules. I've removed all other mods and verified the game files with Steam to check for other possible sources.

2.90 km/s Nitrogen Nuclear Thermal Rocket
- Reactor elements will not fit into the reactor dimensions.

The control rods changed from 0.4 kg Titanium Diboride to 344 kg of Aluminum. Changing the control rods back fixed the error.

234 kW Thermoelectric Fission Reactor
- Criticality Constant does not span Subcritical to Supercritical range.
- Control rods exceeds safety temperature margins.

The control rods changed from Boron Nitride to Aluminum. Changing them to Titanium Diboride fixed these errors.

1.04 MW Thermoelectric Fission Reactor
- Reactor will not fit into the reactor dimensions.

The control rods changed from 11 kg Boron Nitride to 55.2 kg of Aluminum. Changing the control rods to 40 kg of Titanium Diboride and the moderator from 18 kg to 10 kg of Graphite fixed this error.

Won't deleting emission lines break tracers?

Do you want to try my fusion ship?
I think it's time to moving forward about real space travel.

You're welcome!

Thankk you

Turns out there is a character limit for descriptions

Planned changes:
* Lithium, Potassium and Tin from solid to liquid because the first two can't be used as structural materials because they are alkali metals and the latter can't be used as structural material in space because it's not stable when too cold
* some Sodium properties will be changed because they are relative to the solid state
* Lithium, Potassium, Sodium and Tin gases to be used in arc lamps