Discussion of metallic hydrogen propulsion split from another thread.

[sh1pman]

Yeah, I have no problem with metallic hydrogen being in the game. In Kerbal universe it can be metastable, even if it isn't IRL. Jool system is also physically impossible, but it doesn't bother me at all, same here. Treat it like another "Liquid Fuel" - arbitrary resource that's kinda like a real rocket fuel, but doesn't represent any specific one. 

[KerikBalm]

I'd be ok with those engines if they called it "liquid Explodium" or "Mystery Fuel", and didn't promote bad science.

[Guest]

10 minutes ago, KerikBalm said:

I'd be ok with those engines if they called it "liquid Explodium" or "Mystery Fuel", and didn't promote bad science.

I would imagine that to be the easiest mod in the history of KSP mods.

s/metallic hydrogen/liquid explodium/g

 

[Guest]

BTW... why does the Metallic Hydrogen engine look like it has a muzzle break or something?

seems like a lot of stray thrust o_O

Edited February 21, 2020 by Guest

[Guest]

14 hours ago, NoMrBond said:

You're citing one failed experiment as a complete and irrevocably closed door for an entire area of study

No, I'm citing one experiment (it didn't fail, just produced a result you don't like) as disproving a theory (from the 70s, cited in your citation) which predicted metastability in those conditions. Which is exactly what it did. Other theories do not predict metastability at 0GPa, even the one you cited. I should also note, these are theoretical results. They didn't actually discover anything, they predicted metastable forms. Whether hydrogen assumes these forms under any pressure at all is an open question (it doesn't seem to). Recent theoretical work doesn't seem to predict metastabiliy in an usable range. I don't have access to the 70s papers, but given what they could do at the time, the result was most likely something like "well, looks like it might be metastable, hopefully all the way to 0GPa". Basically, the idea that MetH2 would work in a rocket is based on extrapolation of old, inexact theoretical calculations. It was a nice thing to hope for, but not something to bet on.

14 hours ago, Master39 said:

As already stated it's a game that accidentally teaches you things about space, not an educational software, some choices are taken with gameplay in mind and that's ok.

Did you actually watch the video to the end? "Accidentally" was a thing for KSP1, and then only until they realized that and made KSPEdu. KSP2 devs are serious about it being an educational game. Also note, a lot of kids were drawn in by Kerbals, the general public is very much an audience for KSP. It has a way of pulling people in with the little green guys and getting them hooked on realistic physics before they know it, which is a great way of promoting science. Hence why I agree with this:

38 minutes ago, KerikBalm said:

I'd be ok with those engines if they called it "liquid Explodium" or "Mystery Fuel", and didn't promote bad science.

...except that "mystery fuel" has no place in KSP2, IMO.  Indeed, they should explicitly rename LF to methane (having said that's what it is), but that's ultimately just cosmetics. That said, if KSP2 was leaning more towards "lolsokerbal" than "bright future of spaceflight" that the devs stated they were going for, it'd be fine. It's promoting bad science that I hate. I can name a laundry list of mid-range nuclear engines that could fill that gameplay role, and drum up public support for nuclear propulsion (if people see how awesome it is in KSP, they might be more open to trying it IRL). .

[Guest]

It's less about metallic hydrogen itself and more about peddling bad science. We know it doesn't work (the devs don't seem to... yet), so it's irresponsible to tell someone that it does. Spreading myths, especially in popular media, actually does a lot of harm to public perception of science and scientists. Even something as far-fetched as MetH2. People who know better will mod it out. People who don't will be taught a falsehood.

2 hours ago, Brikoleur said:

Personally I don't care. I'm squarely in the "gameplay before realism" camp and if metallic hydrogen rockets make for better gameplay then I'm all for them. "If metallic hydrogen was metastable, this is more or less how they'd work" is more than realistic enough for my needs.

Would you mind if you instead got a liquid core nuclear rocket to fill that niche? It's not that we can't get engines in this performance range, it's that they won't run on MetH2. From gameplay standpoint, there's no reason to keep MetH2 specifically.

Edited February 21, 2020 by Guest

[kerbiloid]

48 minutes ago, Dale Christopher said:

why does the Metallic Hydrogen engine look like it has a muzzle break

It haz.

Also it's a vacuum silencer.

[DStaal]

5 hours ago, mcwaffles2003 said:

I'm surprised more people aren't mad about torchships... way more game breaking IMO

cant wait to use them though :p

IMO as long as the game is balanced and the physics react in a predictable manner I'm pretty happy, just no warp please as that would kill the challenge.

'Torchship' just means the ship meets a pair of somewhat contradictory requirements.  It's likely possible to meet both of them at the same time - it's just not easy and we're not sure what the best way is.  There's no indication in that statement on what tech those are based on.  (Though both Orion and metastable metallic hydrogen are arguably on the edge of being torchships...)

 

3 hours ago, 5thHorseman said:

This made me think of something from Isaac Asimov's Foundation series, where the psychohistorians (people who apply mathematics to social interactions to foresee the future statistically) applied their speech math to a visiting dignitary from (if I recall correctly, it's been a long time) a new, dangerous, and growing political neighbor of theirs.

The analysis was made by people of the First Foundation (not the Second Foundation, which was the psychohistorians), and the dignitary was from the Galactic Empire - in it's waning days.  The point of it was that the First Foundation was still at this point considering itself a research institute, and was expecting the Galactic Empire to save them from their nearer neighbors - and the politician who ran the study was pointing out that the Galactic Empire was saying no such thing, in polite terms - and that they (the First Foundation) needed to step up and protect themselves by becoming a power in and of themselves.

Still the point of the quote was that the dignitary had said a lot and it sounded good - but none of it actually *meant* anything.

[Guest]

14 minutes ago, Dragon01 said:

Would you mind if you instead got a liquid core nuclear rocket to fill that niche? It's not that we can't get engines in this performance range, it's that they won't run on MetH2. From gameplay standpoint, there's no reason to keep MetH2 specifically.

Not in the least.

I do find this entire discussion completely pointless however.

[Guest]

For you, KSP2 is just a game. For most other people, including its developers, it's far more. If you don't understand it, go watch the video, they talk about it at the end.

[Kerbart]

2 hours ago, Dale Christopher said:

Not really, all those things represent real tech which might have been streamlined a bit for gameplay or aesthetics. Batteries charge and discharge, solar panels generate power reducing in effectiveness further away from the sun, reaction wheels are a thing, so is communication. But is it possible to use Metallic Hydrogen as a storable rocket fuel? So far signs point to no, so it might be pure science fiction rather than futurism.

“None of these things work in reality in the way they work in the game”

MH doesn’t seem exceptional to me in that sense.

[Dirkidirk]

You know what else *might* not work

http://www.icarusinterstellar.org/e-beam-icf-for-daedalus-reconsidered/

Spoiler

8 hours ago, kerbiloid said:

It haz.

Also it's a vacuum silencer.

SILENCE VACUUM!

and in mY OpInIOn, a good replacement for the MH engine would be the nuclear salt water rocket.

Edited February 22, 2020 by Dirkidirk

[kerbiloid]

Spoiler

Resource panel: "Meh" for Metallic Hydrogen.

Loading screen: "Forging hydrogen"

 

[Guest]

1 hour ago, Dragon01 said:

For you, KSP2 is just a game. For most other people, including its developers, it's far more. If you don't understand it, go watch the video, they talk about it at the end.

I resent that remark. 

[KerikBalm]

4 hours ago, Dragon01 said:

It's promoting bad science that I hate. I can name a laundry list of mid-range nuclear engines that could fill that gameplay role, and drum up public support for nuclear propulsion (if people see how awesome it is in KSP, they might be more open to trying it IRL).

I hate the promotion of pseudo science as real science, and that's why I wanted to rename it to liquid explodium - no one would mistake it for real science.

I've previously suggested using pebble bed or liquid/gas core designs instead, but that should require more than a simple rename of the part. At this point, it is clear that they are heavily focused on mH engine gameplay, and it seems too late for them to change what would need to be changed if they substituted nuclear engines. It now seems that the choice of lolzKerbal gibberish, and promoting pseudo/ bad science. Between those two, I will take the lolzKerbal gibberish.

3 hours ago, DStaal said:

There's no indication in that statement on what tech those are based on.  (Though both Orion and metastable metallic hydrogen are arguably on the edge of being torchships...)

Metallic hydrogen is nowhere close to being a torchship. It would take impulse trajectories, not brachistichrone.

Orion is arguable. I would call anything taking a brachistichrone trajectory with an acceleration of better than 1cm/sec a torchship (so solar powered ion drives don't count), but from the video, I get the sense that they are talking about something that can get over 1 g constantly.

[KerikBalm]

2 hours ago, Dirkidirk said:

You know what else *probably* doesn't work, at least in the way it does in the game?

http://www.icarusinterstellar.org/e-beam-icf-for-daedalus-reconsidered/

  Reveal hidden contents

SILENCE VACUUM!

 

Well if they explicitly say it is electron beam ICF... then yea, if its instead a more generic ICF engine, I am fine with that.

It seems clear that ICF can work, but it may need to be at a very large scale.

Its a hard engineering problem, but some form of net energy from fusion is possible. We don't have anything right now with a power output less than an exploding nuke, but we do have ways of getting net energy from fusion.

I'd rather have them be vague than wrong.

If all they get wrong is the minimum engine size, I am ok with that.

I am not ok with metallic hydrogen, given the current state of the research, with only very bad predictions from the 1970's to go on (they got the pressures required spectacularly wrong, why put any stock in their other predictions, when there isn't a shred of experimental evidence that agrees with or supports those predictions?)

Edited February 21, 2020 by KerikBalm

[mcwaffles2003]

6 hours ago, Dale Christopher said:

Not really, all those things represent real tech which might have been streamlined a bit for gameplay or aesthetics. Batteries charge and discharge, solar panels generate power reducing in effectiveness further away from the sun, reaction wheels are a thing, so is communication. But is it possible to use Metallic Hydrogen as a storable rocket fuel? So far signs point to no, so it might be pure science fiction rather than futurism.

But the real reaction wheels require desaturation (spinning down), they cant spin infinitely fast and saying "so is communication" glosses over the original point completely. That being yes, communication is a thing, but it doesn't go faster than light.

Battery charging maybe could be linked to supercapacitors, and maybe Kerbol is much brighter than we take it for. 

There's plenty of fiction in this series we all overlook, for gameplay reasons I'll give metallic H a pass.

57 minutes ago, KerikBalm said:

I've previously suggested using pebble bed or liquid/gas core designs instead, but that should require more than a simple rename of the part. At this point, it is clear that they are heavily focused on mH engine gameplay, and it seems too late for them to change what would need to be changed if they substituted nuclear engines. It now seems that the choice of lolzKerbal gibberish, and promoting pseudo/ bad science. Between those two, I will take the lolzKerbal gibberish.

I'm hoping they have designs like this included as well. If the design behind metallic hydrogen says anything it, other than their ties to realism , points to changing nozzles like in KSPIE. Maybe we will see those "pebble bed or liquid/gas core designs" as well. I doubt the devs have laid everything on the table in that episode as far as propulsion goes

[DStaal]

7 minutes ago, mcwaffles2003 said:

There's plenty of fiction in this series we all overlook, for gameplay reasons I'll give metallic H a pass.

True, but those are fictional for gameplay reasons - they're annoying to play with for the majority of users (or were judged so) so their effects were left out, or simplified.  No real tech works like it, but using real tech would be annoying.

Metallic H is one where there are other more realistic technologies that work like it, and even have similar performance envelopes - just with different trade-offs.  They could build the engines based on those instead - or just made something vaguely close to them up.  Instead they're explicitly using a debunked tech.

[Chilkoot]

5 hours ago, Dragon01 said:

For you, KSP2 is just a game. For most other people, including its developers, it's far more. If you don't understand it, go watch the video, they talk about it at the end.

You have to be careful about where you draw the line in suspending disbelief and insisting on realism.  I find it far easier to accept MetH2 in the game than a race of anatomically and evolutionary impossible bipeds that can exist in space for decades with no air, water, or shielding.

If you're going to start saying "It has to be a hard science simulation", then we have to get rid of Kerbals entirely, change the scale of the solar system, eliminate/swap some of the planets, etc.

[mcwaffles2003]

5 hours ago, Dragon01 said:

For you, KSP2 is just a game. For most other people, including its developers, it's far more. If you don't understand it, go watch the video, they talk about it at the end.

This kind of arrogant comment makes me wish there were a thumbs down button, but the 766/4,541 ratio says enough on its own

[genbrien]

8 minutes ago, mcwaffles2003 said:

This kind of arrogant comment 

those are the same people that gets mad when you tell them that Flight Simulators are games. Its a game that simlutate things 

[Guest]

10 minutes ago, Chilkoot said:

You have to be careful about where you draw the line in suspending disbelief and insisting on realism.  I find it far easier to accept MetH2 in the game than a race of anatomically and evolutionary impossible bipeds that can exist in space for decades with no air, water, or shielding.

I draw the line at insisting Kerbals, or any other unreal thing, is real. Now, take a look at that video. They never claimed Kerbals were literally real, for MetH2 they make this claim. Kerbals are obviously fictional and this is perfectly clear from the start. MetH2 is supposed to be real science, and that it's easier to accept than Kerbals is the exact reason it has to go. 

7 minutes ago, mcwaffles2003 said:

This kind of arrogant comment makes me wish there were a thumbs down button, but the 766/4,541 ratio says enough on its own

That I made most of my posts back when the forum had a proper reputation system (which got wiped when we got that sorry excuse we have now)? Or perhaps that I made most of them back when even that wasn't a thing. You younglings' got nothing on me.  

1 minute ago, genbrien said:

those are the same people that gets mad when you tell them that Flight Simulators are games. Its a game that simlutate things 

KSP is a game that teaches things. Which devs said they're going for in the video. Really, if they weren't working "real tech" angle so much, I wouldn't be so hard on them. KSP1 was getting this sort of marketing, too, but KSP2 is all about it, it seems. Rewatch the videos released so far, and tell me, what have we seen more of: fancy new propulsion technology, or little green Kerbals?

[MechBFP]

Metallic Hydrogen is real science though. So in order to use it as a fuel those Kerbal fuel tanks just hold it at 600 Gpa using Kerbal skin and bones as structural support.

Problem solved.

 

[genbrien]

the point is: its still a game
they try to make it realistic in many ways, but call it anyway you want: its a game to have fun

[Guest]

I got to ask you this @Dragon01: are you a high-pressure physicist? If not, what are your qualifications regarding this question? 

I'm not. I'm no kind of physicist.

I have done a bit of looking into this matter and from what I gather, there doesn't appear to be a scientific consensus on this yet. Very few labs have even claimed to have synthesised solid metallic hydrogen. Theoretical models predict a whole bunch of phases for hydrogen, including liquid, solid, and crystalline. Then there are various alloys, notably with lithium, which are predicted to be a great deal more stable than pure hydrogen. Most experts seem to think that sufficiently metastable metallic hydrogen is unlikely, but they seem a lot more cautious about alloys, and they seem nowhere near as certain as you do even about the pure stuff. -- And yes, I'm looking at comments from 2018-2019. So from where I'm standing it looks like the jury is still very much out on this, and in fact if you include dopants and alloys in consideration -- and why wouldn't you? -- then it might be impossible to prove conclusively that metallic hydrogen as rocket fuel is a nonstarter.

Edited February 21, 2020 by Guest