Fuels

[Lo.M]

Fuels;

Topic for general discussion of the types of fuels that will be in the game and also for speculation of fuels.

Confirmed;

• Helium-3 (tralphium)

• Metalic Hydrogen

• Nuclear Pulse 

• METHALOX (the good old liquid fuel)

• Xenon

• Monopropellant (Hydrazine)

• Blutonium (*p) (Few people mentioning about it)  (RTG)

• Solid Fuel (the good old Solid Fuel)

Speculated;

• Uranium
• Helium-2
• Hydrogen (liquid)
• Metastable hydrogen
• Metastable helium
• *Beamed Power and Sails (It's not really a fuel but it's interesting to be here)
• Antimatter (Antiprotons, antineutrons, Positrons, Antihydrogen and Antihelium)
• Hydrogen-Oxygen
• Aluminum-Oxygen
• Argon
• Biofuel
• Monopropellant variants
• Kerosene
• Thorium
• Lithium
• Polonium 
• Bohrium
• Uranium bromide 
• Uranium Hexafluoride
• Hybrid Fuel

 

 

Spoiler

Any more suggestions? Comment for me to add!

 

Edited March 4, 2021 by Lo.M

[Wubslin]

Nuclear salt water rockets apparently have their own dedicated fuel type (maybe 'aqueous Uranium Bromide solution'?). From what we've seen with the swap from Liquidfuel/Ox to being confirmed as Methalox, the folks at Intercept seem intent on abandoning the playful "Kerbal" names for real compounds. And honestly, I'm a big fan of that. One of the central tenets of KSP is teaching real science and physics, yeah? Maybe "Blutonium -238" might just recieve a minor spelling correction sometime soon.

Edited March 2, 2021 by Wubslin

[K^2]

A lot of your image links are broken. Try imgur or some other hosting site.

On topic, antimatter hasn't been properly confirmed, but this to me looks like a beam core antimatter rocket. (From original trailer.)

Spoiler

 

Edited March 3, 2021 by K^2

[minerbat]

if ksp 1 fuels go into confirmed, then solid fuel should be in there. and maybe intake air too

[Lo.M]

16 hours ago, K^2 said:

A lot of your image links are broken. Try imgur or some other hosting site.

On topic, antimatter hasn't been properly confirmed, but this to me looks like a beam core antimatter rocket. (From original trailer.)

  Revelar conteúdo oculto

 

Solved?

Ok added as engine.

[K^2]

2 hours ago, Lo.M said:

Solved?

The links you have to images on a google account aren't working. They seem to be private to your account. You can try to see if there are settings to make them public, or you can re-upload somewhere else.

A good way to do a quick check to see if other people can see your posts is open the page in "private browsing mode," which doesn't use your normal cookies, passwords, cache, etc. It's like logging into a browser for the first time, except you still have your bookmarks and settings. In Chrome or Edge the shortcut is Shift+Ctrl+N. In Firefox it's Shift+Ctrl+P.  That will open a new window with a private browsing tab, and you can just copy the link to the forum page.

[Kernel Kraken]

I wonder if nuclear-pulse engines will damage buildings in-atmosphere and damage nearby ships (or at least give their occupants radiation poisoning) out if atmosphere. It sounds like a fun way to play with your Kerbals for a bit.

[shdwlrd]

1 hour ago, Kernel Kraken said:

I wonder if nuclear-pulse engines will damage buildings in-atmosphere and damage nearby ships (or at least give their occupants radiation poisoning) out if atmosphere. It sounds like a fun way to play with your Kerbals for a bit.

Yes they will. Nate did give a warning about using the Orion drive close to buildings and other ships.

[Lo.M]

3 hours ago, K^2 said:

The links you have to images on a google account aren't working. They seem to be private to your account. You can try to see if there are settings to make them public, or you can re-upload somewhere else.

A good way to do a quick check to see if other people can see your posts is open the page in "private browsing mode," which doesn't use your normal cookies, passwords, cache, etc. It's like logging into a browser for the first time, except you still have your bookmarks and settings. In Chrome or Edge the shortcut is Shift+Ctrl+N. In Firefox it's Shift+Ctrl+P.  That will open a new window with a private browsing tab, and you can just copy the link to the forum page.

I'm going to take the pictures. I'll try for another hosting site.

[K^2]

1 hour ago, shdwlrd said:

Yes they will. Nate did give a warning about using the Orion drive close to buildings and other ships.

I know this is a bit of a tangent, but now I need to know what the smallest NPP size is and can I manage to load it onto an air-to-air missile for some epic dogfights?

[shdwlrd]

17 minutes ago, K^2 said:

I know this is a bit of a tangent, but now I need to know what the smallest NPP size is and can I manage to load it onto an air-to-air missile for some epic dogfights?

I can't imagine it would be small enough to fit on/in an aircraft. Now using it as some type of weird ICBM or SAM, I can see that. Of course since the explosion FX and damage profile would be in the game, I can see a nuke mods being a thing very quickly. 

[Kernel Kraken]

20 hours ago, shdwlrd said:

I can't imagine it would be small enough to fit on/in an aircraft. Now using it as some type of weird ICBM or SAM, I can see that. Of course since the explosion FX and damage profile would be in the game, I can see a nuke mods being a thing very quickly. 

Why would we need nuke mods when we already have them? Just put it on the end of a conventional missile and stage just before impact. I just hope we get different FX for surface, high-atmosphere, and space-based detonations.

[shdwlrd]

47 minutes ago, Kernel Kraken said:

Why would we need nuke mods when we already have them? Just put it on the end of a conventional missile and stage just before impact. I just hope we get different FX for surface, high-atmosphere, and space-based detonations.

I don't know, maybe the bomblets would be considered fuel and usable with only the drive. The drive itself looks to be a minimum size of 3.5 meters. So you wouldn't have access to the bomblets themselves. And the drive would be too large to effectively transport somewhere.

Edited March 4, 2021 by shdwlrd

[Dientus]

2 hours ago, Kernel Kraken said:

Why would we need nuke mods when we already have them? Just put it on the end of a conventional missile and stage just before impact. I just hope we get different FX for surface, high-atmosphere, and space-based detonations.

From what I saw and heard, ksp2 was treating each explosion "like a snowflake". That each would be different and based on whether it is in an atmosphere or not, as well as the type of fuel. It is said to be complex enough that each exploding piece takes into account its neighboring piece, and what it is, does it have fuel, etc.

 

But still, I do not know if uncontrolled nuclear fusion will be a thing or not.

 

Gonna have to fire up the 2 stage ICBM drawings for ksp2 now! As Kerbals, it is our job, nay, our DUTY to find out!

 

[thecodeadd]

Will the nuclear fuels destroy launchpads?

[magnemoe]

On 11/2/2021 at 5:57 AM, thecodeadd said:

Will the nuclear fuels destroy launchpads?

Pretty sure orion pulse nuclear will destroy the pad its an nuke after all. As I understand the engine is also dangerous for nearby ships and structures. 
Also think they said crashing one will set off the nukes, no this is not realistic but fun
Other engines mostly not, an nuclear thermal is not any worse than standard chemicals. 
Border area would be something like an fusion engine, probably work with an large enough pad and cooling, might launch from the sea or have an lake below the pad. 

[SciMan]

Far more likely that you'll need a Sea Dragon sized booster (or a mess of SRBs) to get whatever high-tech drive (that spews radioactive death out the exhaust) to a high enough altitude to fire it up without either glassing the entirety of the space complex that is KSC, or just rendering the whole place radioactive for 100 years.

Gotta remember the Kzinti lesson. Any drive powerful to be "interesting" on the scale of interstellar travel is to be treated with the same amount of respect as a WMD.

And if the nuclear pulse charges do "fail-deadly" when a container of them impacts the ground, well there you go that's your payload for an ICBM right there.

EDIT: Oh and if we have antimatter in the game, well that would obviously make the best payload for a destructive missile, all you need to make it go off is to cut off power to the coils of the magnetic bottle holding the stuff away from the walls of the container keeping it in as close to an absolute vacuum as can be practically managed.

Edited November 20, 2021 by SciMan

[Axelord FTW]

Consider the scene where they showed an Orion drive in the (first?) trailer. The craft used boosters to lift off the pad initially. KSP1 already models exhaust temperature, so it's fair to say KSP2 will too. Mods for the first game that add late-game propulsion engines (like FFT) make use of that after all. Anything directly behind some of those engines on ignition is gone. I'm not actually sure if that is just an effect carried linearly from the engine, though, or if the effect is modeled as a cone. It's not really complicated stuff to implement, really.

One easy drawbacks of (some) high tech engines is their absolute lack of thrust in atmosphere, which is good enough as far as balance go, but for airless world launches, there has to be something that will stop players from just igniting an antimatter torch drive (or whatever else exotic engine) right next to the hab modules.

Edited November 23, 2021 by Axelord FTW

[jimmymcgoochie]

I feel obliged to point out that in the OP’s list, “helium-2” is emphatically not a thing. The only element where the nucleus is solely protons is hydrogen, and that has one proton; adding any more would cause the nucleus to break apart as those positively-charged protons immediately repelled each other. The lightest feasible isotope of helium is helium-3.

I’d also argue that LF/Ox as methalox makes less sense than kerolox- the ISP numbers are too low for pretty much every stock engine (vacuum ISPs of 300-320s for boosters and 330-350s for vacuum engines are exactly what you get with real kerolox rockets- the F1 used on the Saturn V first stage had a vacuum ISP of 305s, similar to the larger booster engines in KSP like the Mainsail, while the Soviet RD-58 upper stage engine had a vacuum ISP of about 350-355s, similar to the Terrier and Poodle), except for the Wolfhound (which matches the vacuum-optimised methalox Raptor’s 380s) and the NERV (which outperforms a methane NTR by about 200s of ISP; putting kerosene into an NTR is laughably stupid), plus the fact that kerosene is widely used as both jet and rocket fuel IRL whereas gas turbines are much less common for aircraft. One possible reason for picking methane instead of kerosene could be for ISRU purposes, since making methane from CO2 and H2O is easier than making long-chain hydrocarbons like kerosene, however unless KSP2 is going to model boiloff and/or buff rocket ISPs to match the better performance of methalox over kerolox it doesn’t make a whole lot of sense to me.

Kerbalism is designed so that LF is assumed to be methane for ISRU purposes, but then it also says that oxidiser is hydrogen peroxide in its ISRU system, possibly to balance the ISP numbers back down to what’s actually seen in KSP; a strange combination of fuel and oxidiser that (as far as I know) has never been used by any rocket.

[K^2]

11 minutes ago, jimmymcgoochie said:

I feel obliged to point out that in the OP’s list, “helium-2” is emphatically not a thing. The only element where the nucleus is solely protons is hydrogen, and that has one proton; adding any more would cause the nucleus to break apart as those positively-charged protons immediately repelled each other. The lightest feasible isotope of helium is helium-3.

It's true that He-2 is not a stable isotope, but your reasoning for why would imply to He-3 and He-4. Adding a neutron does not magically cause repulsion to go away. If anything, it brings protons closer together, increasing repulsion.

Moreover, decay mode for He-2, according to calculations, as it has never been created, would not be by flying apart into a pair of protons. He-2, were it to exist ever so briefly, would undergo beta+ decay, where one of the protons kicks out a positron and turns into a neutron. Rather than two protons, what you'll end up with is a single deuterium nucleus.

Stability of isotopes is nowhere near this simple, and trying to imply intuition based on everyday experience is a sure way to think yourself into a corner. To actually figure out if something like He-2 is stable you have to take into account such bizarre things as virtual meson exchange. Lots of dense math, and absolutely none of it is intuitive.

[jimmymcgoochie]

2 hours ago, K^2 said:

It's true that He-2 is not a stable isotope, but your reasoning for why would imply to He-3 and He-4. Adding a neutron does not magically cause repulsion to go away. If anything, it brings protons closer together, increasing repulsion.

Moreover, decay mode for He-2, according to calculations, as it has never been created, would not be by flying apart into a pair of protons. He-2, were it to exist ever so briefly, would undergo beta+ decay, where one of the protons kicks out a positron and turns into a neutron. Rather than two protons, what you'll end up with is a single deuterium nucleus.

Stability of isotopes is nowhere near this simple, and trying to imply intuition based on everyday experience is a sure way to think yourself into a corner. To actually figure out if something like He-2 is stable you have to take into account such bizarre things as virtual meson exchange. Lots of dense math, and absolutely none of it is intuitive.

Helium-2: exists

Logic: That’ll just fall apart into two hydrogen atoms due to repulsion-

Helium-2: Surprise antimatter! I is deuterium now lol

This is why I’m not a particle physicist…

[OHara]

1 hour ago, jimmymcgoochie said:

Logic: [²He] will just fall apart into two hydrogen atoms due to repulsion-

That seems like sound logic to me.  Nuclei with a proton/neutron ratio much higher than the stable line will happily toss out a proton.

Probably @Lo.M meant something else by "Helium-2", (possibly He₂ as a molecule?) or maybe mistyped.

[K^2]

5 hours ago, jimmymcgoochie said:

Surprise antimatter!

This is now my favorite description of β+ decay and the best thing I've seen today. Thank you.

4 hours ago, OHara said:

That seems like sound logic to me.  Nuclei with a proton/neutron ratio much higher than the stable line will happily toss out a proton.

The heavier the nucleus is, the easier it is for it to shed a nucleon. Nuclear matter soup is way more complicated than electron orbitals, but some of that applies here. Most evidently, if you have just two protons or just two neutrons, they can occupy the equivalent of the s₀ orbital, which is exceptionally stable. This is why ⁴He is so stable. As you go to higher atomic numbers, things get progressively more complex. ¹²C, for example, is shockingly well described as three ⁴He nuclei bound to each other by atomic forces, which isn't something you'd expect if you were guided by the orbital shell model. But ultimately, Pauli exclusion is one thing you can rely on, and you simply cannot have all the protons and neutrons occupy the low energy states. Some nucleons have to have more energy than others, and that becomes more of a factor as you add more nucleons in. At some point, the easiest way to decay is to simply kick out one of the nucleons that already has a lot of energy.

While ²He can decay the same way, the barrier is significant, and energy gain isn't. Again, if you want to know exact branching fractions, you have to do a lot of math, but you can get some sense for it by looking at masses of products. Figuring these out is also a lot of math, but people have done that math, so we can make use of it.

²He - 2.01589amu

¹H - 1.00784amu

²H - 2.01410amu

e⁺ - 0.00055amu

So we can see that 2 ¹H is lighter than ²He, but only just. In contrast, ²H + e⁺ is lighter than either by a more substantial amount. That is, of course, not the whole story. There is also the question of the potential barrier to the decay. The decay to deuterium requires the emission of a W⁺ boson, because the whole process is actually p -> n + W⁺ then W⁺ -> e⁺ + ν. The energy cost of creating a neutrino is negligible, and the W⁺ is virtual, but because the mass of W⁺ is so comparatively high, it's still a relatively slow process. Not as slow as protons overcoming the attractive barrier, however. It is the same barrier that prevents two protons from coming together, and we know that's slow, because this is literal proton-proton fusion. In fact, you can think of p + p -> ²H⁺ + e⁺ + ν process to actually include the ²He²⁺ step, and then subtract the probability of the proton-proton decay from the overall rate. From perspective of underlying physics, the two processes are identical.

[SciMan]

On 11/24/2021 at 6:55 AM, jimmymcgoochie said:

I feel obliged to point out that in the OP’s list, “helium-2” is emphatically not a thing. The only element where the nucleus is solely protons is hydrogen, and that has one proton; adding any more would cause the nucleus to break apart as those positively-charged protons immediately repelled each other. The lightest feasible isotope of helium is helium-3.

I saw that error as well, and I just assumed that they meant "helium-4" instead, which would make an interesting propellant alternative for ion engines (which really don't much care what particular noble gas you put thru them, as SpaceX has shown by their Starlink satellites using ion engines, but using Krypton for the propellant instead of Xenon because it's so much easier to source Krypton than Xenon).
You'll get differences in thrust and ISP based on what particular element you put thru an ion thruster (Usually nobel gases, but also some metals, cesium and mercury were used in extremely early ion thruster experiments, and some modern ones consider using Lithium tho handling that particular chemical element in its molten state is anything but easy). Generally speaking, the heavier the element you put thru the thruster (by atomic mass, not by proton count), the higher your thrust will be but the lower your ISP will be, which follows from what we know of standard chemical rocket engines where hydrolox engines that run significantly hydrogen-rich are the best (practical) chemical rocket engines as far as specific impulse, but their thrust leaves much to be desired, whereas Kerolox engines are at the opposite end of the spectrum.

So, when you put Helium-4 thru an ion engine, what happens?
Out of all the non-radioactive noble gases, when used as reaction mass for an ion thruster Helium-4 will give you the best specific impulse, and the worst thrust. This could be useful for a spacecraft that's intended to have a very high Delta-V, as it's entirely possible to store helium-4 in a supercritical state in lightweight pressure vessels which are well-known, proven technology that has many examples that are available off-the-shelf. The type of pressure vessel I'm thinking of is commonly known in the aerospace industry as a COPV, which stands for Composite Over-wrapped Pressure Vessel. Basically it's a very thin aluminum tank (which actually seals the gas in), which is then wrapped with a lot of high strength fiber in a very specific pattern, with that high strength fiber then impregnated with epoxy to hold it in place (the high strength fiber is what actually withstands the pressure).
The same thing can be done with Xenon, but the problem becomes "where do you get enough of the stuff". I doubt we have even 100 metric tons of Xenon gas stored away at any one time waiting to be used. Back in the '90s I'd have said that most of it is in use in xenon strobe lights and xenon arc lamps, tho in both of those cases white LEDs have made inroads in those areas (for general illumination purposes xenon arc lamps are still quite popular and efficient, and xenon arc lamps can be relatively easily made in a size that requires something like 15kw of electricity to run, which is just a stupendous amount of light).

The reason most ion engines currently use Xenon is that it's one of the easiest noble gases to ionize, and also the most massive per atom that is not radioactive.
This means that using Xenon has two benefits in an ion engine.

Firstly, because Xenon is easy to ionize, little energy is spent performing that task on each atom of Xenon, which is beneficial because all the energy spent ionizing the reaction mass is energy that needs to be input to make the thruster work but it is also energy that can't contribute to thrust.

Secondly, because Xenon is a very massive element by atomic mass, the (notoriously low) thrust of the ion engine is boosted, even tho the specific impulse does suffer.
However, this still ends up being a favorable compromise, as even with using Xenon the specific impulse of the ion thruster will still be far higher than any chemical engine (and many nuclear thermal engines too).

[magnemoe]

30 minutes ago, SciMan said:

I saw that error as well, and I just assumed that they meant "helium-4" instead, which would make an interesting propellant alternative for ion engines (which really don't much care what particular noble gas you put thru them, as SpaceX has shown by their Starlink satellites using ion engines, but using Krypton for the propellant instead of Xenon because it's so much easier to source Krypton than Xenon).
You'll get differences in thrust and ISP based on what particular element you put thru an ion thruster (Usually nobel gases, but also some metals, cesium and mercury were used in extremely early ion thruster experiments, and some modern ones consider using Lithium tho handling that particular chemical element in its molten state is anything but easy). Generally speaking, the heavier the element you put thru the thruster (by atomic mass, not by proton count), the higher your thrust will be but the lower your ISP will be, which follows from what we know of standard chemical rocket engines where hydrolox engines that run significantly hydrogen-rich are the best (practical) chemical rocket engines as far as specific impulse, but their thrust leaves much to be desired, whereas Kerolox engines are at the opposite end of the spectrum.

So, when you put Helium-4 thru an ion engine, what happens?
Out of all the non-radioactive noble gases, when used as reaction mass for an ion thruster Helium-4 will give you the best specific impulse, and the worst thrust. This could be useful for a spacecraft that's intended to have a very high Delta-V, as it's entirely possible to store helium-4 in a supercritical state in lightweight pressure vessels which are well-known, proven technology that has many examples that are available off-the-shelf. The type of pressure vessel I'm thinking of is commonly known in the aerospace industry as a COPV, which stands for Composite Over-wrapped Pressure Vessel. Basically it's a very thin aluminum tank (which actually seals the gas in), which is then wrapped with a lot of high strength fiber in a very specific pattern, with that high strength fiber then impregnated with epoxy to hold it in place (the high strength fiber is what actually withstands the pressure).
The same thing can be done with Xenon, but the problem becomes "where do you get enough of the stuff". I doubt we have even 100 metric tons of Xenon gas stored away at any one time waiting to be used. Back in the '90s I'd have said that most of it is in use in xenon strobe lights and xenon arc lamps, tho in both of those cases white LEDs have made inroads in those areas (for general illumination purposes xenon arc lamps are still quite popular and efficient, and xenon arc lamps can be relatively easily made in a size that requires something like 15kw of electricity to run, which is just a stupendous amount of light).

The reason most ion engines currently use Xenon is that it's one of the easiest noble gases to ionize, and also the most massive per atom that is not radioactive.
This means that using Xenon has two benefits in an ion engine.

Firstly, because Xenon is easy to ionize, little energy is spent performing that task on each atom of Xenon, which is beneficial because all the energy spent ionizing the reaction mass is energy that needs to be input to make the thruster work but it is also energy that can't contribute to thrust.

Secondly, because Xenon is a very massive element by atomic mass, the (notoriously low) thrust of the ion engine is boosted, even tho the specific impulse does suffer.
However, this still ends up being a favorable compromise, as even with using Xenon the specific impulse of the ion thruster will still be far higher than any chemical engine (and many nuclear thermal engines too).

Agree, read helium-2 as an helium molecule  
For ion engines you have 3 factors, the first is ionization energy, how much energy do you need to ionize the element, this is pure loss for the energy used, 2 how heavy it is. An heavier ion give higher trust but lower ISP but for ion engines I say you mostly want trust over ISP
Last is storage, noble gasses stay gas unless cryogenic and an lighter gas need an larger tank for the same ISP. 
For starlink krypton make plenty sense, I assume it will be increasingly popular for cheaper satellites and probes. 
Going down to helium, I guess at this time you rater use other stuff, I would start looking at fusion at this level. 
Ion engines are nice in an small easy to handle engine and power with solar panels.