Preface

Hello everyone!

I'd like to make a thread to compile all player-made standards/presets/etc. for the different modules in the game, in a place where it can be kept updated and organized, so one can always come here to get the latest advice, recommendations, presets, modules, etc.

There are some modules that don't really benefit from presets or user-submitted modules, for instance, Crew Modules, for these kind of modules, it's better to list what materials perform the best, and/or any advice to go with it.

Let me know what you think and feel free to give me any suggestions you may have!

For the sake of not making this post super long, I'll link to pastebin or to the screenshot image, so as to keep all designs in one line

Ideally, the least amount of discussions going on over here, the better; the conclusions are more useful/easier to compile than having to comb over discussions to get the right numbers/suggestions.

Lastly, this threads's ORGANIZED BBCode, is hosted over [here] on GitHub, feel free to submit pull requests, or take it over if I ever disappear.

More importantly, it’s also over here, and anonymously editable, if anyone wants to make my job easier: docs.google.com/document/d/1QfArcpxbmph5hqQDS2aEakpl6gTl55lKblNYLz7UM7M/edit?usp=sharing

Make sure you go to Tools -> Preferences... and disable "Use Smart Quotes", as those will break bbcode when used inside []'s

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Submodules

Turbopumps

Turbopumps are used for cooling modules, such as Reactors, Launchers, and Lasers, or as the main mechanism, Pumps, in Refueler modules.

There are two things that are important for these, the composition, which ideally should be the cheapest material that can handle the forces involved in the submodule, and the Pump Radius/Rotational Speed ratio, which controls how the weight/cost to efficiency ratio.

For low temperature Turbopumps, Lithium is by far the best material, for being the cheapest available; once its limits are broken, or when high temperature is rquired, materials such as Diamond/Amorphous Carbon should be used instead.

On my LRR 10 MW Reactor (not the most optimized), the inner loop (2500 K) uses Diamond as the material, here's a table describing the efficiency of the turbopump. I changed the Rotational Speed only, and adjusted the Radius until the reactor stopped having issues due to inner loop overheating.



I would love to know how to process this data to get the best ratio, but I've no idea how to do so.

Getting anything cheaper than 12 kc seems impossible with fiddling with the values manually, so it seems a ratio of ~0.5 cm/RPM is the best for price.

Getting anything below 355 kg (@ 26cm / 400rpm) seems impossible fiddling with the values manually, so it seems a ratio of 0.065 cm/RPM is the best for weight (with a price of 12.2kc, so it seems ~0.06cm/RPM is pretty close to an ideal ratio).

Perhaps the ratio changes depending on the power level of the reactor? Confirmation needed

Perhaps the ratio changes depending on the composition of the turbopump? Confirmation needed

(Credit apophys for material research)

According to apophys, optimum rotating speed in reactors is usually somewhere between 400-600 RPM. Too low, and the coolant in the pump adds mass. Too high, and the bracing adds mass. For different reactors, the optimum is different. (Factors that affect this are unknown.)

Applications other than reactors can use slower rotating speeds, because there is less penalty on a larger size.

Below is a list of useful materials for turbopumps:



In order to find the optimal ratio for a turbopump for your own specific reactor, you'll have to inch the size of the pump up (if starting with a small pump radius) or down (if starting with a large pump radius), then the rpm adjusted until you get the results you want (e.g. efficiency, weight, cost, watch whatever you want to optimize against) and/or you get rid of the warnings.

You can do this with a few different sizes, and you'll find there's a most efficient/sweet spot. If sizing up makes things worse size down or vice versa, at some point the improvements get reversed, and that's where the sweetspot is.

Injectors

Same thing as Turbopumps, except these aren't affected by temperature.

Gimbal/Turrets

Similar to Turbopumps, Lithium is the best material for reaction wheels due to its weight. However, in turrets, reaction wheels consume power, and lots of it, and ideally, one would go for the most power-efficient material and turret diameter combination.

While Li seems to be the best as far as weight/cost for rotation wheels it's very difficult to get decent speed on low power turrets. So far the best I've found for <1 Mw designs is Magnesium. (Credit randomletters)

(Credit apophys for the following material research)



(Credit amimai for the following material research)

Tests per mass equalized on turret armor:

Lasers: (12x 1.5 MW output, 5 MW intensity) (measured as time to kill 20 turrets)
Nukes: 10MT nukes at 6km detonation
Shrapnel: 20 missiles carrying 600m/s 700x6g + 10x500g frags detonating at 1.5km range (amimai: Could you clarify what the Shrapnel test results mean?)



Conclusion: For general purpose you want Amorphous Carbon, its cheap, its strong, its a wonder material, and you only need around 4mm to stand up to most things.

For money and 'murrica and EXTRA FREEDOM!, you can use Silicon Aerogel, it is as good vs lasers, balls at stopping any projectile, but will survive the Soviet Nuclear Alpha Strike.

Boron is pretty good as armour if you are particularly working to counter kinetics, but otherwise fairly bad.

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Does anybody know what the best diameter to rotational speed ratio is? It seems to be ~0.065 if it's the same as with injectors/turbopumps.

Rocket Engine Nozzles

I'm fairly sure NASA has some information on these...

These vary a lot, but it would be great to know the best ratio/s between added volume vs added exit velocity.

What are the best nozzle configuration in your opinion?

Do you think we can come up with a few presets?

Most efficient vs smallest

Missile nozzles vs Capital Ship nozzles

Personally, I've been using Boron or Amorphous Carbon for cheap nozzle material.

(credit apophys) For low mass and size, it is very important to keep throat radius small, because that controls the scaling of the entire nozzle.

Recommended material: diamond. It has very high thermal conductivity, very low thermal expansion, very high melting point, and high yield strength.

Thus, it will not easily crack from thermal stress, and it will have no difficulty spreading and radiating away its heat.

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Propellants & Propulsion

Propellants (non-chemical) for NTR and Resistojet Propulstion

In order of usefulness.

Feel super extra free to correct and improve this! Starting out with a short/incomplete list for my sanity's sake, as it takes a while to compile all the data.

I'm aware people have been using Decane and others, but haven't done so myself so I don't have the information to quickly add it to this list.

Propellants (Chemical)

(Credit: zuthal)

Hydrogen/Fluorine is the best propellant mix ingame. Delivers up to 5.1 km/s of exhaust velocity (at stoichiometric ratio), while being denser than all of the common NTR fuels (At an 18.8:1 Fluorine:Hydrogen ratio by mass, the average density of both is ( 18.8 * 1696 + 70.85 ) / 19.8 = 1614 kg/m^3, compared to 422.62 kg/m^3 for methane and 730.05 kg/m^3 for decane). Hydrogen/Fluorine rockets are, however, not really viable for MN-scale engines, due to combustion chamber heat issues.

Additionally, the inconvenient mixture ratio constrains the minimum total fuel mass to 2 kg. Also, the realism is sketchy, due to both a limited supply of Fluorine in the solar system and the rather... difficult chemistry of fluorine, especially when hot. PTFE tanks should realistically be able to hold it, though (as PTFE is already maximally fluorinated).

Volumetric impulse (how much impulse you get out of one cubic meter of propellant, calculated as exhaust velocity times propellant density) for an optimal HF chemical engine (5100 m/s exhaust velocity) is 8.23 MN*s*m^-3, or the normalised volume usage as used by apophys, is 0.122 m^3*MN^-1*s^-1. Thus, if your ship is small enough to use them, HF chemicals clearly beat any NTRs.

Here's a spreadsheet for all chemical fuels in the game, with a methane and a decane NTR for comparison (in light blue.) Credit to zuthal for this whole section, and hats off for making such a complete spreadsheet!

These are the most useful four:

Resistojet Propulsion

Suggested Materials Table

MPD Propulsion

(Credit apophys)

Vanadium Chromium Steel is very strong, which makes smaller MPDs. However, it reduces the GW/kg fuel you can put in significantly

(Credit amimai)

For ideal materials, check out amimai's designs. Cost for MPDs are really a non-issue, so you can go wild. (There's also a suggested materials table below based on this as well.)

For MPD systems, it's ideal to aim for ~50 GW of power. For Neon and Mercury, the saturation point is about ~45 GW, beyond which gains are flat. Below that point, however, you get more thrust per kg of fuel.

If you are going to use MPD as backup thruster for a combat ship use Methane as the main ship propellant, it allows 10 x more MW/g flow and gives higher fuel efficiency for small MPDs.

Suggested Materials Table

Propellants

Propellants for MPDs can be nearly everything, but the best propellants are ideally dense and cheap. Here we list three (feel free to submit more), in order of usefulness for MPD thrusters.



While Mercury can burn straight out most planet's gravity wells, with Neon you will often find you need to slingshot and gravity assist your way out that can add weeks or months to journey time.

Some number crunching by amimai

Density / 1k: Roughly correlates to dV/m^3 of fuel
SQRT adjust: More meaningful in some cases
10g/100g/1kg/4kg: Propellant flow rate

Modules

Propellant Tanks

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Thermoelectric Fission Reactors

Reactors

With enough fiddling you can get close to 10 MW (60 MW total heat) out of 100 grams of U-233 dioxide at 97% enrichment. So every value below that is going to be some lower enrichment value of 100 grams U-233 dioxide.

To be min-maxed for cost, use the lowest possible enrichment value, with the highest possible neutron flux to generate enough heat to leech the amount of power you want.

So if you want ~1 MW at 2400 K you need ~6.06 MW waste heat. You calculate that by taking the power you want and dividing that by the max thermocoupler efficiency rating for your outlet (16.5% for 2400 K so 1/.165 = ~6.06).

Max sustainable Neutron Flux is a little more tricky so I just kind of eyeball it based off previous reactor results for neturon flux stability (avoiding the reactor burning through fuel too fast error is the real pain).

After you get your reactor outputting the correct amount of waste heat you just need to make it not melt with turbopumps and a large enough thermocoupler. To be the highest efficiency possible you want it to be right on the brink of melt down, and thermocoupler yield strength. If you find yourself more meltdown prone than yield strength prone, reduce the size of the thermocoupler (or vice versa).

(credit jasonvance)

See Turbopumps above for advice on how to find the best size/rpm ratio.

Modules

Reactor Submission Template:

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Reactor Temperature

Reactors are best run at 2400-2500 K

2300 K most efficient, bigger radiatiors
2400 K best tradeoffs ^{[citation needed]}
2500 K
2600 K less efficient, smaller radiators

(If I remember correctly, the thermocouple can't reach the best delta-Temperature on 2600 K, making 2500 K the "best" choice for this...? I could be spouting nonsense tho^{[citation needed]})

(Credit amimai:)
Side notes on reactor designs :
- Higher neutron flux is better for radiation, mass and size
- Adjusting moderator allows for higher neutron flux

It's important to note that temperature changes reactor behaviour with size:

2400 K: Larger reactors, more efficient.
2500 K: Larger reactors, marginaly more efficient.
2600 K: Smaller reactors, More efficient. (Significantly so, ~5% gain for every 50% output reduction.)

(Credit n2maniac for the information table below.)



There's also these graphs based on amimai's table/information, based on his [reactor]

According to him, for designs over 2500 K, it is possible to make "heavy" reactors, maximizing power/heat at the cost of weight; these were added to data set (under spoiler below) (notably HV2600 reactors are marginally better then 2500 for radiator area)

Original info:

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Neutron Reflectors / Radiation Shiels

Lithium-6. That's pretty much it, it's orders of magnitude better than anything else, use it as an external radiation shield and don't bother with neutron reflectors.

On the other hand, if you DO want to bother with Neutron Reflectors, use Boron. Reactor too hot for Boron? Use Boron Nitride (cost optimized) or Boton Carbide (weight optimized).

Anything else is not really comparable. Have a graph, graphs are cool!



If you want to minimize radiation generation on a reactor, use a skinny reactor design. (credit jasonvance)

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Coolants

In order of usefulness for nuclear reactors. Let me know if you think I should include more/less properties!

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Radiators

Best Radiator Material based on Temperature


* RCC is more expensive than the step up, but less massive nonetheless

Credit jasonvance for this!

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Payloads

Nuclear Payloads

Nuclear Payload Submission Template:

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Weaponry

Lasers

(Credit apophys for this whole section)

You have effectively 2 choices for your laser medium: Green (Nd:YAG + Krypton) or Purple (Ti:Sapphire + Xenon).
Green is more raw power (higher efficiency), but requires larger apertures to make up for its lesser intensity (Green is lower frequency than Purple). Purple has somewhat improved efficiency at low power, but still not more than Green.

Green gets its best pumping when arc lamp radius is small. Purple gets its best pumping when arc lamp radius is large. This makes Purple slightly more expensive when optimized, in my experience. (Most of your cost will be turret armor.)

Increasing lamp radius requires also increasing lasing rod radius, which worsens M². Higher power input also worsens M², but increases intensity. You want M² to be 3.00-3.02 or else your intensity at range takes a hit.

For these reasons, I recommend Purple for low power (<100 MW) and Green for high power (>100 MW, arbitrary cutoff by me).

Cavity shape is best when it is as close to a circle as possible. Keep dimensions small; this saves a lot of mass (mostly as coolant) at a low efficiency cost.

Transparent parts are Fused Quartz.

Cavity wall and internal mirror are Silver (standard) or Copper (if you want to sacrifice efficiency to push your output temperature up for smaller radiators).

Use a frequency doubler for a greatly reduced aperture, and thus greatly reduced weight and cross-section. It is strongly recommended but not essential; you can choose to take the cost of a large aperture if for some reason you really want a laser in the near infrared.
Silver Gallium Selenide always gets you to 100% efficiency here, and it is the only one to do so. Its cost and weight are negligible. Therefore no other doubler is relevant.

Focusing mirror is aluminum (for Purple) or silver (for Green or near infrared).

The turret should be as small as possible to hold the aperture, due to reaction wheel mass being added.

Crank up engagement range to 1 Mm, because that's what lasers are for. If you're getting terrible intensity, increase the aperture. Aim for at least 1 or 100 MW / m2

Following these guidelines, you can get effective lasers in a few tons of weight, or even less.

(Credit amimai for the following)

Turret Sizes

On turret sizes for Offensive Lasers, for 45.1° (minimum turret design for light flywheels), spot diameter is not proportional to laser power output, only m²-rating changes spot diameter:

Ablation and Critical Intensities

(Credit zuthal for this whole section)

Critical Intensity: Laser intensity above which more intensity in a single laser results in no more increase in ablation rate.

The maximum ablation rates of various materials are calculated under the assumption that the game ignores heat of vaporisation/decomposition (which seems reasonable, as they would likely be otherwise noted for armour materials) and that it has 0 K as the ambient temperature.

[Have a spreadhseet]

Coolants

In order of usefulness for lasers. Let me know if you think I should include more/less properties!

Hydrogen or hydrogen deuteride are the only coolants that really make sense, because it doesn't need to work very hard and it must take a lot of space.

Design Guidelines/Philosophies

Apophys: Dedicated Offence Glass-Cannon Lasers

Amimai: Compact Secondary Weapons

Modules

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Kinetics

Conventional Guns

Rail Guns

Rail Guns are lighter than Coil Guns.

(credit amimai)

Rail Guns have 2 peaks for velocity depending on bore radius, one at 5mm or less, this is best for projectiles and gives high velocity, the second one at 2cm or more, this gives the best performance when launching payloads.

Good Barrel Materials:
Zirconium Copper (Best Speed)
Aluminum Copper Lithium (33% less speed, 50% less mass/cost)

Good Projectile Materials:
Amorphous Carbon: Good for light, Super Velocity Rail Guns; causes minimal barrel stress at 50km/s+ velocities
Osmium: Good for Heavy Mass Rail Guns; you can safely, and effectively, launch 100g of this at 30km/s+ velocities

Good Shuttle Materials (for shooting payloads):
Osmium: For narrow payloads; 100g payload to 20km/s
Beryllium: For wide payloads; expensive but best
Aluminium Zinc Magnesium: For wide payloads; cheap, 5% slower (than Beryllium)
Gamma Titanium Aluminium: For hot payloads (ie, if shuttle material melts); cheap, 15% slower, 100 times more thermostable (than Beryllium)

On Rail Gun Warnings:

If the projectile shatters, try lowering velocity
If the barrel ruptures, increase projectile mass (which does not decrease velocity)

Coil Guns

Good Barrel Materials:
Aluminium Copper Lithium: It offers 25% lower velocity, but is 4x as light, matching results of rail guns (not that this matters, a 60 MW 1g, 51km/s rail gun has a mass of only 5t)