Discussion of metallic hydrogen propulsion split from another thread.

[KerikBalm]

On 2/28/2020 at 10:40 AM, kerbiloid said:

They should find a way to make the metallic hydrogen expansion statistically improbable.

They should find a way to make water changing phase in a vaccum statistically improbable.

They should find a way to make free energy machines failing to work improbable.

You might as well say

They should find a way to make it so that something that doesn't work, does work.

[kerbiloid]

11 minutes ago, KerikBalm said:

They should find a way to make water changing phase in a vaccum statistically improbable.

They should find a way to make free energy machines failing to work improbable.

You might as well say

They should find a way to make it so that something that doesn't work, does work.

I just follow the logic of the university course of statistical physics, distribution of particles = distribution of probabiity.
While the water analogy is correct, the "doesn't work - does work" analogy is less relevant.

The electrons in the atom are distributed between discrete orbits due to quantum effects.
The atoms in a crystal structure are also distributed discretly.

So, they should find out a quantum effect which makes improbable relocation of a metallic hydrogen "atom" to the outside.
And to make the air molecules gather in one half of a room.

Maybe some specific pattern of electromagnetic field making existence of a proton at particular place probable/improbable, or so.

Upd.
Currently they affect the statistic redistribution only by a piston pressure (or what they use else).
Probably, they should try some other ways to manage the local distribution of probability.

Edited February 29, 2020 by kerbiloid

[SciMan]

Can we solve the problem @KerikBalm has with Metallic Hydrogen engines and fuel by simply renaming them to some form of handwavium? It's a game after all, we don't play games for everything to be realistic.

IMO KSP is NOT a simulation, it's a game that makes heavy use of simulation elements but it's not in itself a simulation. RSS and the associated mods do turn it into a simulator, but the base software is still a game.

Don't expect me to reply much to this, I rarely pay attention to the forums anymore.

[PlutoISaPlanet]

If you dont like a engine dont use it

[KerikBalm]

On 7/1/2020 at 9:57 PM, SciMan said:

Can we solve the problem @KerikBalm has with Metallic Hydrogen engines and fuel by simply renaming them to some form of handwavium?

I'm fine with calling it the PSM engine, and the vacuum variant the PSM^2 : its the purple space magic engine.

On 7/8/2020 at 2:44 AM, PlutoISaPlanet said:

If you dont like a engine dont use it

I won't. However, I also have a problem with dissemination of false information as if it were true. Before you bring up "its just a game", #1) note how many people on the forum will defend it as a real possible tech, #2) @Nate Simpson has publicly stated he thinks its real tech (citing studies that only show his ignorance on the subject, but whatever).

Renaming it to the PSM engine solves this issue, so I'd be fine with SciMan's renaming, as long as the renaming doesn't make people think that it is real tech just on the horizon/near future tech that is coming soon™ 

[SOXBLOX]

Okie doke. There is not enough data to rule out the existence of your "purple space magic". mH almost certainly exists under high pressures. The debate is over whether it can be made to remain stable at more reasonable pressures. Fact is, no one knows. And even if pure mH is unstable, it might be possible to introduce impurities into it, stabilizing it. A metallic hydrogen alloy, if you will. I certainly don't mind it in my game.

[Snip] We have no way to say one way or the other. And why would you care if a bunch of crazed teens think its coming "real soon now"? That's their problem, not yours, sir.

Edited July 23, 2020 by James Kerman
redacted by a moderator

[Davi SDF]

This forum has not been the same since KSP2 developers said "metallic hydrogen", my flipping rocket god (kraken)!

[Bej Kerman]

On 7/1/2020 at 8:57 PM, SciMan said:

Can we solve the problem @KerikBalm has with Metallic Hydrogen engines and fuel by simply renaming them to some form of handwavium?

What would Handwavium be doing in a KSP game? Metallic hydrogen is one thing, made up stuff is another.

On 7/1/2020 at 8:57 PM, SciMan said:

we don't play games for everything to be realistic.

But KSP isn't just a game.

[DunaManiac]

26 minutes ago, Bej Kerman said:

What would Handwavium be doing in a KSP game? Metallic hydrogen is one thing, made up stuff is another.

 

What about Liquid Fuel, Monopropellant, Oxidizer etc?

[KerikBalm]

Before the whiners come: Note that I am merely responding to a post directed at me, made 10 days after my last post on the subject of mH. It seems other people don't want to drop the subject either.

Also, recently I was criticized for a lack of citations (even though I've cited all this stuff before), but I again find myself replying to a post by someone who seems not to have seen the citations, and isn't aware of the actual state of the science. 

18 hours ago, SOXBLOX said:

Okie doke. There is not enough data to rule out the existence of your "purple space magic".

Indeed, and we can't disprove the existence of unicorn farts as a viable form of propulsion, nor pixie dust. So would you would be ok if KSP 2 added unicorn fart engines, pixie dust, and purple space magic engines, alongside engines based in actual science?

Quote

mH almost certainly exists under high pressures.

No one has been arguing otherwise.

Quote

The debate is over whether it can be made to remain stable at more reasonable pressures. Fact is, no one knows.

There's not much of a debate, fact is that a study came out in 2019, which apparently made metallic hydrogen, and measured its properties, and determined that it was not metastable.

https://arxiv.org/ftp/arxiv/papers/1906/1906.05634.pdf

*edit* I was getting citations from my old posts, but the paper is out of pre-print and past peer review now:

https://www.nature.com/articles/s41586-019-1927-3

Quote

Upon pressure release, the metallic state transforms back to the C2/c-24 phase with almost no hysteresis

...

The vibron frequency shift with pressure was reversibly observed upon pressure decrease (see Extended data Fig. 6)

Upon pressure release, the infra-red transmission is discontinuously recovered and the pressure evolution of the IR absorbance of the hydrogen reversibly measured with pressure ( see Extended data figure 5). 

 

Quote

And even if pure mH is unstable, it might be possible to introduce impurities into it, stabilizing it. A metallic hydrogen alloy, if you will.

Biut we've already looked at alloys of it, because those are much easier to make, and they still need will 100-165 GPa of pressure:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2764941/

Even with lithium, you have over 1 kg of lithium for 1 kg of hydrogen% - pebble bed NTR outperforms it. We've also tried deutrerium- doubles the MW of the exhaust, and pebble bed NTR outperforms it.

The Lithium alloying example linked above only allows the compound to be stable in the range over >100 GPa, so compared to a shuttle tank at about 250 kPa.

100,000,000 kPa vs 250 kPa... you need a tank holding 400,000x more pressure, if that is related proportionately to mass, then the engine is non-viable

But that cited paper was a prediction, and like the predictions about mH itself, it underestimated the pressures (the ealier predictions had numbers much lower than 415 GPa):

https://pubmed.ncbi.nlm.nih.gov/26056306/   where we see thos allows predicted to be metallic at around 100-165 GPa, remained non-metallic up ot at least 215 GPa), and further modelling predicted even higher pressures: https://pubmed.ncbi.nlm.nih.gov/28318270/

And another study of different alloys, but this time looking for superconductors at high temperature (and still hundreds of GPa): https://pubmed.ncbi.nlm.nih.gov/28630301/

https://physicstoday.scitation.org/do/10.1063/PT.6.1.20180823b/full/ (note that its not a prediction, but measured properties)

 

Quote

The point being, your calling the concept false shows your ignorance. We have no way to say one way or the other. And why would you care if a bunch of crazed teens think its coming "real soon now"? That's their problem, not yours, sir.

We do have ways of saying, a "way of saying" is a prediction, we can turn to physics, and make predictions, which all say: No

In summary: We've measured mH's properties, its not metastable. We've looked into alloys, they decrease the required pressure to form it, but fail to bring metastability, and still require pressures of over 100 GPa to stabilize it. These alloys would increase the propellent MW by enough to make it inferior to solid core NTRs, while requiring a tank over 400,000x stronger than what we make now (and not even carbon nanotubes would be strong enough to contain the pressure, as their tensile strength would be a maximum of about 63 GPa. https://en.wikipedia.org/wiki/Mechanical_properties_of_carbon_nanotubes

So, lets say carbon nanotubes have about half the strenght required to contain a metallic hydrogen alloy (which will already suck because you have more lithium than hyrogen in it), 63GPa for the tubes, 126 for the alloy, or 50 for hte tubes, and 100 for the alloy (depending on how optimistic you want to be for each figure).

Now, between 55-115 GPa, you also have carbon starting to transform into Diamond. (the general pressure being different than the tension that the tubes would experience)

To contain such a pressure with a tank, using carbon nanotubes, you'd need the nanotubes enclosing the tank to be sqrt(2) the radius of the tank, so that the pressure is spread out over a surface 2x larger. Now, between the tubes and the surface of the tank, you'd probably have diamond, because that's what we currently use to contain high pressure metals made out of elements that are normally non-metallic (FYI, there's also metallic oxygen, metallic Nitrogen, etc, that can be made at high pressures, and these have been studied as well - they don't need as high of a pressure as hydrogen does... and none of them are metastable either).

This means that for a tank of metallic hydrogen 10 meters wide, you'd need at least 4 meter thick wall of diamond, and then you'd have to wrap that in carbon nanotubes. Then as soon as you release even a little pressure, you get a BLEVE, just like tryingto use supercritical water as an energy storage.

https://en.wikipedia.org/wiki/Boiling_liquid_expanding_vapor_explosion

Which is not suitable for a continuous thrust rocket.

if you want to say that we may be wrong, well, maybe magic exists, we may be wrong. Maybe pixie dust exists, you can't prove it doesn't! "You can't prove it doesn't is a horrible standard for including something in science fiction, you might as well, just have the "miracle" drive or the "god does it" drive.

 

but ... yea... sure, just say I'm ignorant, because, despite all the evidence and science saying that its not possible... I can't disprove it in the same way that I can't disprove the existence of magic... ok then.

 

Edited July 20, 2020 by KerikBalm

[Bej Kerman]

15 hours ago, DunaManiac said:

15 hours ago, Bej Kerman said:

What would Handwavium be doing in a KSP game? Metallic hydrogen is one thing, made up stuff is another.

  On 7/1/2020 at 8:57 PM, SciMan said:

What about Liquid Fuel, Monopropellant, Oxidizer etc?

It's called Liquid Fuel, not Grassanium. Liquid Fuel is clearly a stand in for many fuel types that power chemical engines.

2 hours ago, KerikBalm said:

if you want to say that we may be wrong, well, maybe magic exists,

Metallic Hydrogen is magic in the same way that controlled explosions propelling cylinders to space is magic to people who existed centuries ago.

[KerikBalm]

2 hours ago, Bej Kerman said:

Metallic Hydrogen is magic in the same way that controlled explosions propelling cylinders to space is magic to people who existed centuries ago.

"Metallic Hydrogen" is not magic - metastable Metallic hydrogen is. Stop conflating this. Furthermore, centuries ago, people were building internal combustion engines. An ICE engine was patented in 1794, 226 years ago, which is centuries ago. *edit- read explosions propelling cylinders and thought ice: rocket engines aren't explosions, but rockets have been in use since the 13th century. It would hardly seem like magic to them - while it would be very impressive, they would recgonize what the machine was doing

You are again (and again and again) basically arguing "you can't prove its impossible beyond any doubt", which is true of literally anything, so a Unicorn fart engine is also equally magic with a metallic hydrogen engine, using your criteria.

Edited July 20, 2020 by KerikBalm

[Bej Kerman]

9 minutes ago, KerikBalm said:

"Metallic Hydrogen" is not magic - metastable Metallic hydrogen is. Stop conflating this.

Whatever

10 minutes ago, KerikBalm said:

An ICE engine was patented in 1794, 226 years ago, which is centuries ago.

You get my point.

10 minutes ago, KerikBalm said:

You are again (and again and again) basically arguing "you can't prove its impossible beyond any doubt", which is true of literally anything, so a Unicorn fart engine is also equally magic with a metallic hydrogen engine, using your criteria.

Metallic Hydrogen may be impossible, but you can't be certain.

[KerikBalm]

14 minutes ago, Bej Kerman said:

You get my point.

I'm guessing your point is essentially that, as Asimov put it, "Any sufficiently advanced technology is indistinguishable from magic"

Quote

Metallic Hydrogen may be impossible, but you can't be certain.

Any you can't be certain that unicorn farts can't be used as an even better rocket fuel. You can't be certain that magic doesn't exist/isn't real.

Since the criteria you are advocating for is the lack of absolute certainty, and one can't be absolutely certain of anything (hard solopsim), it logically follows from your position that literally anything should be acceptable in KSP2, and there is no possible argument to be made against anything they put in, regardless of how ridiculous it is.

[sarcasm]I will look forward to purple space magic engines, unicorn fart engines, GMO popcorn engines, and miracle drives alongside metastable metallic hydrogen engines in KSP.[/sarcasm] All of them are equally scientific!

[DunaManiac]

3 hours ago, Bej Kerman said:

It's called Liquid Fuel, not Grassanium. Liquid Fuel is clearly a stand in for many fuel types that power chemical engines.

 

Yes, but Liquid Fuel is Handwavium. I don't understand how it would be any different from Handwavium. It is in essence, a "made up fuel", it doesn't quite match any Lf-Ox mix in real life. As long as it has the same stats as Metallic Hydrogen, it would please everyone to rename it to some kind of handwavium.

Edited July 20, 2020 by DunaManiac

[DStaal]

15 minutes ago, DunaManiac said:

 

Yes, but Liquid Fuel is Handwavium. I don't understand how it would be any different from Handwavium. It is in essence, a "made up fuel", it doesn't quite match any Lf-Ox mix in real life. As long as it has the same stats as Metallic Hydrogen, it would please everyone to rename it to some kind of handwavium.

It's not Handwavium because it's an abstraction - it's stats are similar to multiple existing fuels, if not quite the same as any one of them.  Therefore instead of having the two dozen or so existing fuels (and associated engines, tanks, etc) in KSP, we have one that is roughly the same as all of them.  It's stats are realistic, just not real.  No problems are being handwaved away, they're just being simplified for gameplay.

MH is explicitly trying to be real, and there's no real-world counterpart.  All the problems with it are being handwaved away.

[SOXBLOX]

I argued that the data isn't good enough to rule out metastable mH, not that it is impossible to disprove its existence. There is an obvious difference.

[Bej Kerman]

48 minutes ago, DStaal said:

1 hour ago, DunaManiac said:

Yes, but Liquid Fuel is Handwavium. I don't understand how it would be any different from Handwavium. It is in essence, a "made up fuel", it doesn't quite match any Lf-Ox mix in real life. As long as it has the same stats as Metallic Hydrogen, it would please everyone to rename it to some kind of handwavium.

It's not Handwavium because it's an abstraction - it's stats are similar to multiple existing fuels, if not quite the same as any one of them.  Therefore instead of having the two dozen or so existing fuels (and associated engines, tanks, etc) in KSP, we have one that is roughly the same as all of them.  It's stats are realistic, just not real.  No problems are being handwaved away, they're just being simplified for gameplay.

MH is explicitly trying to be real, and there's no real-world counterpart.  All the problems with it are being handwaved away.

Exactly. It isn't handwavium in the sense that it isn't something that can't exist. It's just a generic stand in for existing fuels to make designing rockets less needlessly difficult.

1 hour ago, KerikBalm said:

Any you can't be certain that unicorn farts can't be used as an even better rocket fuel. You can't be certain that magic doesn't exist/isn't real.

Except that we've checked if there's no unicorn farts that can be used as rocket fuel. Spoiler alert, there's no unicorn farts that we can use as rocket fuel.

1 hour ago, KerikBalm said:

[sarcasm]I will look forward to purple space magic engines, unicorn fart engines, GMO popcorn engines, and miracle drives alongside metastable metallic hydrogen engines in KSP.[/sarcasm] All of them are equally scientific!

I hope you're not expecting a comedy award for this.

28 minutes ago, SOXBLOX said:

I argued that the data isn't good enough to rule out metastable mH, not that it is impossible to disprove its existence. There is an obvious difference.

Precisely.

[KerikBalm]

4 hours ago, Bej Kerman said:

we've checked if there's no unicorn farts that can be used as rocket fuel.

What a ridiculous and obviously false statement

4 hours ago, Bej Kerman said:

Spoiler alert, there's no unicorn farts that we can use as rocket fuel.

How did you determine this?

How can you argue in favor of this statement in a way that wouldn't be equally valid by just replacing "unicorn farts that we can use as rocket fuel" with "metallic hydrogen that is metastable at low pressure"?

[Bej Kerman]

3 minutes ago, KerikBalm said:

4 hours ago, Bej Kerman said:

we've checked if there's no unicorn farts that can be used as rocket fuel.

What a ridiculous and obviously false statement

Care to explain why?

3 minutes ago, KerikBalm said:

Quote

Spoiler alert, there's no unicorn farts that we can use as rocket fuel.

How did you determine this?

How can you argue in favor of this statement in a way that wouldn't be equally valid by just replacing "unicorn farts that we can use as rocket fuel" with "metallic hydrogen that is metastable at low pressure"?

We've got enough data to tell that there's no fuelling unicorn farts. We haven't got enough data to determine if MH can be MS at LP. Besides, I never said that I know for sure that LPMSMH exists.

[KerikBalm]

18 hours ago, Bej Kerman said:

18 hours ago, KerikBalm said:

What a ridiculous and obviously false statement

Care to explain why?

Because its ridiculous to claim that "we've checked if there's no unicorn farts that can be used as rocket fuel"  

[snip]

 

18 hours ago, Bej Kerman said:

We've got enough data to tell that there's no fuelling unicorn farts. 

What a ridiculous and obviously false statement. Please cite our data regarding unicorn farts, and their properties that make them unsuitable for use as rocket fuel.

Please tell me how you think the above quoted statement can be logically valid, but this one isn't: "We've got enough data to tell that there's no fuelling unicorn farts metallic hydrogen that is metastable at low pressure." 

Note: mere assertions neither constitute evidence nor a logical argument.

18 hours ago, Bej Kerman said:

We haven't got enough data to determine if MH can be MS at LP

"We haven't got enough data to determine if MH can be MS at LP unicorn farts can be used as rocket fuel."

"We've got enough data to tell that there's no fuelling unicorn farts metallic hydrogen that is metastable at low pressure." 

These last two statements of mine are actually MORE valid than your statements, because we do have data on the properties of metallic hydrogen (suggesting it won't be metastable at any relevant pressure), and we have absolutely no data on unicorn farts.

Edited July 21, 2020 by Snark
Redacted by moderator

[Snark]

Quite a bit of content has been removed, due to,

• being off-topic (e.g. arguing about arguing)
• telling people what to do or not to do
• making personal remarks

Folks, let's please remember that we're all pals here and conduct ourselves accordingly.  It's never okay to make personal remarks about other people.  It's also not okay to tell other people what to do-- you're not a moderator.  And please stick to the topic at hand, e.g. discussing metallic hydrogen as a KSP2 fuel, without haring off into off-topic blather about whether someone is arguing "appropriately" or not, or about their posting habits, or the like.

And take it down a notch, please.  People are getting way too worked up about this, to the point that they're slinging insults around.  Please try to keep a sense of perspective.

To be clear, here are some inarguably true statements:

• There are people who like that KSP2 will have metallic hydrogen, for what they believe to be good reasons.  And this is a perfectly reasonable position to take.
• There are people who dislike that KSP2 will have metallic hydrogen, for what they believe to be good reasons.  And this is a perfectly reasonable position to take.
• There are people who don't really care about the issue, for what they believe to be good reasons.  And this is a perfectly reasonable position to take.

All of those people are perfectly entitled to their own opinions.  It's perfectly okay for all of those people to state their opinions.  The mere fact that their opinion happens not to agree with yours does not constitute an attack on you, so it's not something worth getting worked up about.

It's perfectly understandable to feel compelled to argue against someone, if their opinion differs from yours, and if their stated reasons seem like "bad" ones to you.  It's a natural human impulse, because, well, duty calls. 

But please remember that the same things aren't important to everyone.  Different people have very different priorities, and nobody is ever in a position to call someone else's priorities "wrong".

So.... remember that, please.  If someone has a different opinion than you about what's "right", most likely it's because they simply have different priorities than you, not necessarily that they're "misinformed" or being "unreasonable".  Their opinions are reasonable... given their priorities.

We now return you to your lively discussion, already in progress.    Please try to keep it friendly, folks.  Feel free to explain your opinions, but please try to keep the discussion focused on your rationale, and on metallic hydrogen and/or its role in KSP2.  As soon as you start focusing on other people's behavior and why they're "wrong", you're veering off the rails, so please try not to head off into the weeds.

Thank you for your understanding.

 

[K^2]

On 7/20/2020 at 8:17 AM, SOXBLOX said:

I argued that the data isn't good enough to rule out metastable mH, not that it is impossible to disprove its existence. There is an obvious difference.

It's starting took bad for metastability. The tests that have been ran aren't exactly flawless, but the fact that they haven't found any signs of metallic hydrogen even at fairly high pressures, while backing off from the point where they did detect it, suggests that it's probably not all that stable even at high pressures, and that doesn't say good things about pressures in which you'd care to store it in a rocket.

Granted, there are still a few things you can do to extend metastability, like dropping temperature, doping the material, adding a magnetic field... But I would hold out hope on that if we've seen any indication of metastability at least at high pressure, which we haven't. So the space of possibilities under which MSMH is a viable fuel is rapidly shrinking. Based on data we have now, I'm comfortable calling it "very unlikely".

[KerikBalm]

Its pseudo-science at this point.

There was one paper from 48 years ago, using a now thoroughly disproven model, that predicted the possibility of metastability.

In the 48 years since then, no model predicts metastability, and no experimental evidence shows any hint of meta-stability - the experimental evidence includes alloys and isotopes, in addition to pure protium mH.

The only response possible is that our knowledge of the universe is not perfect, which applies to literally anything, unicorn farts included.

[snip]

Edited July 22, 2020 by Snark
Redacted by moderator

[Guest]

[snip]

"It might work because a KSP2 dev believes so" is the way some people look at it, because KSP had made quite a reputation for its scientific accuracy, and hence has, believe it or not, built up scientific credibility. 

Edited July 22, 2020 by Guest
Redacted by moderator