Worried about KSP magic tech, unrealistic orbital mechanics, and lol-explosions

[Guest]

Just now, Brikoleur said:

No it's not.

Metallic hydrogen. And you're right, it's not. Alcubierre drive is still in "might or might not work" category, while metallic hydrogen drives are in "most likely about to be disproven" one. I would be very, very surprised if they were possible after all.

[Geschosskopf]

28 minutes ago, Dragon01 said:

Wrong. What they agreed not to do is claim ownership of any extraterrestrial land. As for high ground, check out Battle of Flodden.

Bad analogy   I bet you've never been a war yourself, and been tasked with taking a hill.

The thing about the Moon is that it's way up Earth's gravity well.  It can easily bombard the whole planet while retaliating, or defending against that, is extremely difficult.  Read The Moon is a Harsh Mistress by Heinlein.

Anyway, the reason for not owning the Moon is specifically to prevent somebody turning it into an orbital fortress.  So nobody's ever going to be able to establish anything there big enough, or permanent enough, to become a threat.

 

28 minutes ago, Dragon01 said:

Yeah, like that has ever stopped anyone. Seriously, you've got governments sitting on hundreds of nuclear warheads. What makes you think they'd stop developing a fusion drive just because you can turn it into a particle beam?

You missed the point entirely.  I was just noting that Orion isn't the only space drive capable of destroying civilization.  They all can.  Otherwise, they wouldn't work as space drives.  So nobody should think that Drive X is any safer than Orion simply because it doesn't actually use nuclear bombs.

 

28 minutes ago, Dragon01 said:

Then you're a complete physics-illiterate. Metallic hydrogen is at the same level as Alcubierre drive. Inertial confinement fusion, on the other hand, has been demonstrated, multiple times, in National Ignition Facility and its predecessors. In fact, in NIF they had achieved breakeven, which means the process is, very theoretically, capable of being turned into a power plant, or a self-powering engine. Now, the whole thing takes up a large building, so it's not quite on the level of NTR technology as far as readiness goes, but it does not require new physics.

I beg to differ.  Metallic hydrogen can be shown to exist, and its properties anticipated, for exactly the same reasons as with neutronium.  Or that various types of fusion, which we will never likely to be able to replicate, go on in the hearts of very large stars.  They all play by the same rules.

Also, NIF did not achieve breakeven as that has always been defined, and did not achieve actual ignition.  It got closer than before, but it failed.  And now they'd pretty much given up on the inertial confinement project. Go back and read about it.  Here's the easy version.

The most promising fusion thing currently in the pipeline is magnetic confinement, on which billions are currently being spent by pretty much everybody.  Having a commercially viable system is still decades away, however.

[Technical Ben]

1 hour ago, Brikoleur said:

Where does the reaction mass come from? 

They still use hydrogen. It's not a magic drive. Even Expanse AFAIK has reaction mass. They just don't generally mention it, to avoid breaking the suspension of disbelief by making an error (cast/actors could say "1kg of fuel" instead of "1 kilo tons of fuel" for example).

On twitter I follow a couple of game devs. Aiming for hard-sci-fi ship design. They designed the craft around a sphere of lithium (or Metallic hydrogen/lithium mix etc). It was only 1/3 of the ships *size*, but accounted for the 90% mass for the TMR of the craft (fusion rocket using laser confinement IIRC).

So as long as the Kerbstine drive uses normal fuel (it probably will, it may be multimode, and burn through each fuel quicker etc), then it will be fine. It's just a fusion drive shrunk and made 99% efficient (our cars are like 99% efficient currently, after the poor 25% fuel to oxygen combustion cycle that is ). With fusion drives, you would get limits in efficiency, but for a game, you can dial up to 11.

 

PS, What is it with people? Lol. The Alcubierre drive is pure fantasy, and we don't even know if the physics exists for it. Metallic Hydrogen has possibly been made (in science you tend to need a few more examples to prove no error has been made, so we need a couple more productions of it). It is possibly metastable in some compounds (mixing with lithium or something). So, given 100 years? We might be able to get a fuel tank (still under pressure!) with it in. This gives you good size vs weight vs thrust/reaction mass. It's still super expensive to make. But possibly a few orders of magnitude less than antimatter production and containment.

Colony making is also, plain and simply, the gameplay mechanics that allows you to build craft on/orbiting around a planet. That speeds up play/tests/trials/missions as you can, once a colony is kitted out, save on the few years transit time. It leads to more emergent gameplay. IIRC they said you'd have to bring parts across to build craft first, then later industry/kerbals can build the parts for you. So as a stepping stone, we get gradual tech/gameplay progressions.

 

Unless someone is using cheats, no one will be flying to another system at lightspeed in a self building ufo on day one... after a few days or months in game play? Then perhaps you could kit out a giant self sufficient orbital landing craft launcher, that also runs on antimatter pumped He4 fusion torches fed from buzzard collectors. XD

Edited August 27, 2019 by Technical Ben

[Guest]

1 hour ago, Technical Ben said:

They still use hydrogen. It's not a magic drive. Even Expanse AFAIK has reaction mass. They just don't generally mention it, to avoid breaking the suspension of disbelief by making an error (cast/actors could say "1kg of fuel" instead of "1 kilo tons of fuel" for example).

That's my problem right there. You have relatively small ships capable of maintaining 10G as good as indefinitely. You'd need to accelerate the exhaust plume to within a gnat's whisker of c to make reaction mass last. How do they do that? The LHC does that to a handful of particles at a time and it has a circumference of 27 km and is bleepin' huge. Similarly, we have some rough designs for fusion-driven starships, and they're mostly reaction mass. 

I'm no physicist but until someone explains how they make a necessarily very small amount of reaction mass work like it works in the books and TV show, I'm filing it with Star Trek's warp factor 9. 

(In fact one of my pet peeves about The Expanse is that people treat it like it was hard sci-fi although it really isn't, not even the authors started claiming it is until relatively recently. Like, no, you couldn't spin up Ceres to have Martian-equivalent centrifugal gravity near the surface without having it fly apart, and no, fusing the crust into glass wouldn't help.)

Edit: I'm watching Manley's video right now, and he starts off by calling them "magic sci-fi space drives" and explains that they're mostly story devices. Watching the rest of the video now but so far it's not really helping your realism case.

Edit 2: Finished Manley's video. He points out that a fusion-based Epstein drive would vaporise the craft it's on with only its waste heat. So, effectively, but very nicely and politely, saying that it is science fantasy, not science fiction.

Edited August 27, 2019 by Guest

[Guest]

16 minutes ago, Geschosskopf said:

The thing about the Moon is that it's way up Earth's gravity well.  It can easily bombard the whole planet while retaliating, or defending against that, is extremely difficult.  Read The Moon is a Harsh Mistress by Heinlein.

I did. Take a look when it was written (hint: before Apollo 11). Or the Outer Space Treaty, for that matter. All those "Moon as orbital fortress" stuff were mostly 60s-era concerns. Gravity gauge is not as useful as you might think. If something tried to pull "bombardment with lunar rocks" today, they would be able to get a few shots off before all their ammunition got stranded in orbit by ASAT weapons damaging the retromotors, or shattered by kinetic-kill missiles and burned up in atmosphere. Then Earth would retailate, and not by sending atomic warships to slowly land and be crashed, but by sending ballistic nukes. Which the loonies wouldn't be able to stop because guess what, no atmosphere and no weapons capable of physically destroying a nuke. Expensive, yes, but hardly impossible if you can colonize the moon in first place. It's just a matter of putting MIRV warheads on a lunar rocket and developing avionics for targeting them onto the Moon. Nevermind that you don't need a computer and fancy sensors to help you land in reality, seeing as Apollo 11 touched down under manual control, you only need a window and a good pilot. So if they wanted to invade, they could do that, too. Heinlein was writing under assumptions of his time, which, while not unreasonable, did not work out the way he thought they would. 

High ground remains a tactical advantage. It's just that sitting there is not going to win you the war. Of course, taking a hill is not an easy task for grunts, but faced with such a situation as a commander, however, my answer would be "shell it until either the enemy is gone, or the hill is". High ground or not, stopped=dead in modern warfare. You can lie in ambush for a while until you're discovered, at which point, you move. Stealth and movement are the name of the game, and you don't get the former in space. As it turns out, you don't get too much of the latter, too. You might move fast, but you move predictably, and that's the same as not moving at all in military terms. You either invest in a dV-heavy propulsion system to help you dodge, or your enemies have six days for your enemy to track your entirely ballistic payload, target it with whatever they want, and intercept it. For perspective, Israel won a war in six days. If the Arabs had a lunar fortress (a silly notion, but it's just for comparision), the first shot would be entering atmosphere (probably reduced to pebbles by ASAT weapons) by the time the war was over. In modern warfare, you're either hidden from sight, hidden from fire (usually behind civilians, seeing as there are very few physical objects that can stand up to modern penetrating weapons), or moving so erratically that you're very hard to hit. Even combat aircraft mostly do low level strikes these days.  

38 minutes ago, Geschosskopf said:

You missed the point entirely.  I was just noting that Orion isn't the only space drive capable of destroying civilization.  They all can.  Otherwise, they wouldn't work as space drives.  So nobody should think that Drive X is any safer than Orion simply because it doesn't actually use nuclear bombs.

Orion isn't exactly the best choice for destroying civilization, either. In fact, unless it's really gigantic, the pulse units tend to be rather wimpy in nuke terms. TBH, you could cause nuclear-level destruction by just aiming a Saturn V-sized rocket at the target (the N1 obliterated its own pad that way). You need actual WMDs to actually cause a world-ending catastrophe, however. A mishap/misuse of a space drive can be very destructive, but it won't end civilization.

39 minutes ago, Geschosskopf said:

I beg to differ.  Metallic hydrogen can be shown to exist, and its properties anticipated, for exactly the same reasons as with neutronium.  Or that various types of fusion, which we will never likely to be able to replicate, go on in the hearts of very large stars.  They all play by the same rules.

Yeah, and there are many scientists who say it won't be metastable. 

[Zacho]

Just to add a few things, the engines in the Expanse are super fusion rockets. They have higher ISP to let the story they wanted to tell work. They use water as reaction mass. If you want to learn more about fusion torch ships this is the best place to go. http://www.projectrho.com/public_html/rocket/torchships.php

Time to read up on Brachistochrone trajectories!

Edited August 27, 2019 by Zacho

[KerikBalm]

2 hours ago, Geschosskopf said:

I beg to differ.  Metallic hydrogen can be shown to exist, and its properties anticipated

Nobody is arguing that metallic hydrogen doesn't exist. The drive succeeds or fails on it being metastable at low pressures. This part we cannot anticipate, as our models couldn't even correctly predict to within an order of magnitude the pressures at which metallic hydrogen will form, so do you really think they are valuable for telling you the pressure at which it will be metastable?

We cannot anticipate its metastable properties at this time, and we have none to examine. I suspect it will not be very metastable, and when created, it won't remain metallic when the pressure is released (it would be awesome if I'm wrong though).

And yea, ICF fusion is much harder than initial estimates, but a tellam-ulam design is in essence an ICF design, with x rays from a fission weapon replacing the lasers. Its also for this reason that a lot of ICF-fusion research is thinly veiled weapons research to improve modelling of warheads that they can't test anymore.

https://en.wikipedia.org/wiki/Thermonuclear_weapon#Public_knowledge_concerning_nuclear_weapon_design

Quote

Though large quantities of vague data have been officially released, and larger quantities of vague data have been unofficially leaked by former bomb designers, most public descriptions of nuclear weapon design details rely to some degree on speculation, reverse engineering from known information, or comparison with similar fields of physics (inertial confinement fusion is the primary example).

Its the same concept, we know you get ignition if you pump enough energy into it fast enough. Fission bombs can do that... Lasers can, we know, because we're able to achieve any fusion at all with them. So far though, we've built some really huge facilities, and its still not igniting, meaning with current tech the laser array needs to be even more massive. If the light could be delivered more uniformly on the target, yields would go up, but slight irregularities in the focusing dramatically drop fusion yields. To some extent, we need more precision - but its nothing prohibted by the laws of physics.

Right now ICF isn't a question of possibility, but of practicality.

On the other hand, if metallic hydrogen isn't metastable, an intrinsic property of the material, any such engine is dead in the water.

 

1 hour ago, Brikoleur said:

Finished Manley's video. He points out that a fusion-based Epstein drive would vaporise the craft it's on with only its waste heat. So, effectively, but very nicely and politely, saying that it is science fantasy, not science fiction.

Exactly why I'm fine with fusion drives that have orders of magnitude less thrust... I don't care if you say its an ICF drive, a polywell, a z-pinch device, etc... we know fusion works (tsar bomba! 97% fusion energy), and I'm willing to handwave the details since its operating on an established principle.... but don'tgive it an Isp and thrust level that means that you need 99.99% efficiency (or something like that) to avoid instant vaporization.

High Isp and high thrust = utterly ridiculous power output levels... talking about terawatts and petawatts, which means that even at 99.9% efficiency the waste heat is in gigawatts and terawatts...

We're talking power output levels higher than the orion drive #1) where the fusion reactors are thermonuclear bombs #2) where the reaction happens outside the spacecraft.

An epstein drive would require the ship to handle a thermonuke going off inside it many times per second... 

No

[M_Rat13]

We are talking about interstellar travel here, something that many people already consider in the realm of fantasy. Big problems require big solutions, and the fact we can still point to the real world and go 'look, this is meant to represent that', is an achievement in itself.

My only real worry, is if these new engines make a planet like Eve, easy to get off of. As Matt Lowne has said, Eve is the boss mode of KSP 1. To take away that boss mode in KSP 2, would make the game feel too easy. Regardless of the tech we have, KSP should always have something to challenge us.

[Geschosskopf]

3 hours ago, Dragon01 said:

I did. Take a look when it was written (hint: before Apollo 11)

Well, if you read it, you misread and misinterpreted it.  The laws of motion haven't changed in the last half-century or somebody would have told me  

But hey, you also misread/misinterpreted everything else you've gone on about, including asserting easily verifiable untruths.  Your your ridiculous ideas about military operations here are just more of the same.  And you have loudly trumpeted your utterly incorrect positions without any attempt at polite debate, leading off your posts with name-calling.  So I'm done talking to you.

 

1 hour ago, KerikBalm said:

Nobody is arguing that metallic hydrogen doesn't exist. The drive succeeds or fails on it being metastable at low pressures. This part we cannot anticipate, as our models couldn't even correctly predict to within an order of magnitude the pressures at which metallic hydrogen will form, so do you really think they are valuable for telling you the pressure at which it will be metastable?

It seems to be rather more likely than not.  That's why they're trying to make it.  If the anticipated outcome was that it wouldn't be stable, they wouldn't have gotten the funding.  And from my understanding, they know about what pressure it would happen but just couldn't get there before.  The question about pressure is whether it can be reduced later on with some clever manufacturing technique, or so I understand.  But I readily admit I'm no expert on this subject, although I do watch with interest from the sidelines.

 

1 hour ago, KerikBalm said:

Right now ICF isn't a question of possibility, but of practicality.

Sure, your basic H-bomb eventually results in ICF but going that route is just Orion with different ammo.  That's a rather different thing from the ICF drive concept, which is basically an open-cycle reactor.  The "practical problems" of the ICF drive (or even just an ICF powerplant reactor) seem rather more difficult to solve than they are for Tokamaks, which is what everybody's betting on right now.  And they're still saying it's several decades away.  Nobody's that optimistic about ICF or they'd still be pursuing it.

 

20 minutes ago, M_Rat13 said:

My only real worry, is if these new engines make a planet like Eve, easy to get off of. As Matt Lowne has said, Eve is the boss mode of KSP 1. To take away that boss mode in KSP 2, would make the game feel too easy. Regardless of the tech we have, KSP should always have something to challenge us.

Nobody is going to hold a gun to your head and force you to SSTO from Eve to a distant star.  If you don't want to do that, then don't.  If others want to, and it's possible, then let them.  It's really not your business how other people play their games.

[M_Rat13]

3 minutes ago, Geschosskopf said:

Nobody is going to hold a gun to your head and force you to SSTO from Eve to a distant star.  If you don't want to do that, then don't.  If others want to, and it's possible, then let them.  It's really not your business how other people play their games.

I'm not saying someone shouldn't be allowed to do something, just that it shouldn't be trivial. If anyone could easily do return missions involving Eve, what would make it different from any other planet?

[Geschosskopf]

1 minute ago, M_Rat13 said:

I'm not saying someone shouldn't be allowed to do something, just that it shouldn't be trivial. If anyone could easily do return missions involving Eve, what would make it different from any other planet?

Everybody ALREADY can make effortless returns from Eve (or anywhere else).  Just open the cheat menu and select infinite fuel.

Again, you have a perception that what other people do in the privacy of their own games somehow impacts you when it really doesn't.  When folks talk of their missions, they explain how they did them (if it wasn't obvious from the pics).  We've had a host of mods for years that allow Eve SSTOs, not to mention various conservation-breaking stock props and ladder drives.  If somebody uses one of these (or just the fuel cheat), they know it and you know it.  So how does that cheapen your accomplishment if you do things the hard way?

[M_Rat13]

10 minutes ago, Geschosskopf said:

Everybody ALREADY can make effortless returns from Eve (or anywhere else).  Just open the cheat menu and select infinite fuel.

Again, you have a perception that what other people do in the privacy of their own games somehow impacts you when it really doesn't.  When folks talk of their missions, they explain how they did them (if it wasn't obvious from the pics).  We've had a host of mods for years that allow Eve SSTOs, not to mention various conservation-breaking stock props and ladder drives.  If somebody uses one of these (or just the fuel cheat), they know it and you know it.  So how does that cheapen your accomplishment if you do things the hard way?

Ok, further clarification. I'm talking about stock KSP (+DLC), with no cheats.

[Guest]

2 hours ago, Geschosskopf said:

Well, if you read it, you misread and misinterpreted it.  The laws of motion haven't changed in the last half-century or somebody would have told me  

No, they didn't. It's just that there's more to orbit to orbit combat than laws of motion. Laws of aerodynamics, for instance, which tend to bias any engagement in favor of an atmospheric planet. What changed is technology, which developed in ways that would have been hard to foresee in the 60s. Keep in mind that Heinlein's writing isn't a gospel (not even Stranger in a Strange Land). He was good, but many of his predictions turned out to be way off. 

If those untruths are "easily verifiable", then go on, verify them. I stand by what I said. You made no attempt at refuting my statements, just a blanket assessment that they are wrong. This is not how debating works. Give me one reason why a modern nation, equipped with ASAT weapons and a space program on its own, would be unable to destroy, in six days, a non-maneuvering piece of rock coming at them from the Moon.

[Technical Ben]

6 hours ago, Brikoleur said:

That's my problem right there. You have relatively small ships capable of maintaining 10G as good as indefinitely. You'd need to accelerate the exhaust plume to within a gnat's whisker of c to make reaction mass last. How do they do that? The LHC does that to a handful of particles at a time and it has a circumference of 27 km and is bleepin' huge. Similarly, we have some rough designs for fusion-driven starships, and they're mostly reaction mass. 

I'm no physicist but until someone explains how they make a necessarily very small amount of reaction mass work like it works in the books and TV show, I'm filing it with Star Trek's warp factor 9. 

(In fact one of my pet peeves about The Expanse is that people treat it like it was hard sci-fi although it really isn't, not even the authors started claiming it is until relatively recently. Like, no, you couldn't spin up Ceres to have Martian-equivalent centrifugal gravity near the surface without having it fly apart, and no, fusing the crust into glass wouldn't help.)

Edit: I'm watching Manley's video right now, and he starts off by calling them "magic sci-fi space drives" and explains that they're mostly story devices. Watching the rest of the video now but so far it's not really helping your realism case.

Edit 2: Finished Manley's video. He points out that a fusion-based Epstein drive would vaporise the craft it's on with only its waste heat. So, effectively, but very nicely and politely, saying that it is science fantasy, not science fiction.

[edit]

Never mind. I never claimed that there were not problems with the heat etc. But that the energy/mass ratios are correct. If you had containment. KSP also has no life support, timewarp, zero degradation of materials/fuel etc... so having a heat impervious fusion drive, is not beyond the realms of the game.

 

PS, not sure how you got that from the video. 4 or 5 tons fuel per ton of payload sounds rather reasonable for a fuel source meeting "scifi" levels of visual sizes. But you'd need metallic/compressed hydrogen to fit it nicely in most scifi ships. Though most scifi has nowhere for fuel to go. XD In KSP you will need tanks. Magnetic confinement could also be a thing. It's "future", not "magic" tech.

"as good as indefinitely", nope, as long as you get from tons of hydrogen having fusion work on it. Like nuclear power, this gives days/hours of use. See current nuclear fuel use rate.

 Finally, In expanse there are no radiators. In KSP, you need radiators!

Edited August 27, 2019 by Technical Ben

[Geschosskopf]

6 hours ago, Brikoleur said:

Edit 2: Finished Manley's video. He points out that a fusion-based Epstein drive would vaporise the craft it's on with only its waste heat. So, effectively, but very nicely and politely, saying that it is science fantasy, not science fiction.

That's why I analogize space opera as unicorns (interplanetary/interstellar ships) farting rainbows (speculative space drives) as they fly between fairy castles (major colonies all over the place).  All staples of space operas are indistinguishable from magic.  None can actually exist with foreseeable technology and even if the technology existed, if nobody can make money at it, it's not going to happen anyway.

HOWEVER, I'm quite willing to suspend my disbelief because the concept is just as enjoyable to imagine as a swords-and-sorcery epic.  I grew up during the height of the space race, watching it on a small B&W TV, and reading all the classic SF works by the great masters.  I believed at the time I'd be living on a Jovian moon by now.  So naturally I grew up into a bitter, disillusioned old man.  CURSE YOU, PHYSICS!  As such, I enjoy playing space games I know to be fantasy because they bring back the happily expectant mental state of my misspent youth.

So basically, the announced features of KSP2 mean it's a given that there will be magic (speculative high-tech).  So accept it as magic and don't look under the hood.  Magic can't stand up to scientific scrutiny--no matter how far you dial it down, it's still magic.  So, just as the author of The Expanse declines to say how his drive works, don't worry about how KSP2 drives will work.  The whole idea of a meaningful interplanetary civilization, let alone interstellar, cannot exist without such magic.  Otherwise, the Kerbals would be just as stuck on Kerbin as we are on Earth.  Where's the fun in that?

[chaos_forge]

3 hours ago, Geschosskopf said:

It seems to be rather more likely than not.  That's why they're trying to make it.  If the anticipated outcome was that it wouldn't be stable, they wouldn't have gotten the funding.  And from my understanding, they know about what pressure it would happen but just couldn't get there before.  The question about pressure is whether it can be reduced later on with some clever manufacturing technique, or so I understand.  But I readily admit I'm no expert on this subject, although I do watch with interest from the sidelines.

That's . . . not how science works. At all. It's not like they're getting contracts to produce industrial quantities of the stuff. The funding is so they can produce some in order to find out if it's metastable or not. Because they entire point of the government funding research is so we can do experiments that are useful but not necessarily profitable. There's no theoretical consensus at the moment as to whether metallic hydrogen is metastable or not, because doing theoretical quantum physics is really hard.

[DrRansom]

On 8/26/2019 at 8:52 PM, Geschosskopf said:

While I understand your concerns, you're actually complaining about the wrong thing   The magic actually comes from the interplanetary stuff.  The interstellar stuff is just the logical outgrowth of the interplanetary stuff.

Ahahaha that's so true. Colonization - and especially self-sustaining life support - is basically space-magic already. 

I wonder if Metallic Hydrogen was conceived as necessary for interstellar travel. It serves as a high DeltaV / Mass fuel, which can be carried on interstellar ships and carry colony supplies from orbit to the surface. That way, the developers can constrain the power of interstellar ships to something reasonable, say <0.3c to avoid any special relativity effects, and still give players enough fuel to make a reasonable landing attempt. 

[Geschosskopf]

22 hours ago, chaos_forge said:

That's . . . not how science works. At all. It's not like they're getting contracts to produce industrial quantities of the stuff. The funding is so they can produce some in order to find out if it's metastable or not. Because they entire point of the government funding research is so we can do experiments that are useful but not necessarily profitable. 

When was the last time you applied for government funding?   I usually do it once or twice a year and rarely succeed.  Believe me, they don't just give you money if they don't think the result will be of some practical benefit.  And even if it might, you're not the only one asking for money so your project has to compete with the apples-and-oranges projects of everybody else with their hands out.  Some of whom are probably in the district of one of the guys on the committee, and you're not.  So a lot of it comes down to salesmanship.

So, imagine yourself as the king.  2 alchemists come asking for funding.  Each gives a different sales pitch.

Alchemist #1:  I want a gazillion dollars to try to produce metallic hydrogen.  Just cuz it's cool to crush stuff at extreme pressures.  I have no idea if this will provide any benefit, but we can at least show the world we can squeeze stuff the hardest.  And the crushing machine might explode, which would be cool to see.

Alchemist #2:  I want a gazillion dollars to try to produce metallic hydrogen.  This is because I believe it will be metastable.  If so, then it will have all sorts of both practical uses and general scientific benefit.  That will make you, Highness, even richer than you already are.  While there is some debate amongst alchemists as to whether it will be metastable or not, the preponderance of the evidence leans in that direction (produces lots of papers on the subject; for you and your court magician to examine, which do indeed seem to show there's a better chance of success than failure). 

So, which one, or both, or neither will you fund?  Your court magician is shrewd and will look around for more papers the 2nd guy might not have brought along, just to check his story.  If the court magician finds a lot more negative papers, he'll recommend the 2nd guy get burned at the stake for attempted fraud.  But if the 2nd guy's story checks out, then it's your call. 

EDIT:  But you have to balance this against some nuns who want to build an orphanage and similarly unrelated but compelling projects all asking for your money.  Which one(s) are most likely to keep the peasants from revolting?  Which one(s) will generate the most tax revenue?  Which one(s) are reasonable things nobody will argue about?  Which one(s) appeal to your fancy and are cheap enough to slip in with nobody noticing after you've hit the high points?

 

20 hours ago, DrRansom said:

I wonder if Metallic Hydrogen was conceived as necessary for interstellar travel. It serves as a high DeltaV / Mass fuel, which can be carried on interstellar ships and carry colony supplies from orbit to the surface. That way, the developers can constrain the power of interstellar ships to something reasonable, say <0.3c to avoid any special relativity effects, and still give players enough fuel to make a reasonable landing attempt. 

Who can say?  But I got the opposite impression from watching that interview where the dev identified the metallic hydrogen engine as being on the Mun lander's transfer stage, whereas the ships seen in other solar systems had ginormous ICF-looking engines.  So I was seeing metallic hydrogen as a sort of improved LFO, for like the landers of the colony stuff, whereas the interstellar motherships carrying all the colony stuff (and the landers for it) are of the torch ship variety, to reduce travel times.

Edited August 28, 2019 by Geschosskopf

[Guest]

Sadly @Geschosskopf is right.

t. married to an academic

[KerikBalm]

10 hours ago, Geschosskopf said:

It seems to be rather more likely than not.  That's why they're trying to make it.  If the anticipated outcome was that it wouldn't be stable, they wouldn't have gotten the funding.  And from my understanding, they know about what pressure it would happen but just couldn't get there before.  The question about pressure is whether it can be reduced later on with some clever manufacturing technique, or so I understand.  But I readily admit I'm no expert on this subject, although I do watch with interest from the sidelines.

No, just no. #1) The research into metallic hydrogen has value whether or not it is meta stable. #2) The mere possibility that it is meta stable would warrant further investment even if we don't know if its more likely than not. #3) There's no clever manufacturing technique that can save it if its not metastable, it would be an intrinsic property of the material. That's like saying you could have a clever manufacturing technique to have water remain liquid in a vacuum, or have an ice cube remain solid at 100 C.

 

10 hours ago, Geschosskopf said:

Everybody ALREADY can make effortless returns from Eve (or anywhere else).  Just open the cheat menu and select infinite fuel.

Again, you have a perception that what other people do in the privacy of their own games somehow impacts you when it really doesn't.

And in my private game, I want an engine with a reasonable acceleration, and I want to feel like if I use the engines and craft available, the craft will be realistic in overall qualities (even if the colonies aren't, and stuff like engine starting and part wear isn't modeled). If there aren't just tiny cracks in reality, but gaping chasms, then that puts everything into doubt.

I'd rather leave the magic tech as a mod... like KSP did. You want farther future tech, get it in a mod (like you can in KSP already).

6 hours ago, chaos_forge said:

That's . . . not how science works. At all. It's not like they're getting contracts to produce industrial quantities of the stuff. The funding is so they can produce some in order to find out if it's metastable or not. Because they entire point of the government funding research is so we can do experiments that are useful but not necessarily profitable. There's no theoretical consensus at the moment as to whether metallic hydrogen is metastable or not, because doing theoretical quantum physics is really hard.

+1

2 hours ago, Geschosskopf said:

When was the last time you applied for government funding?   I usually do it once or twice a year and rarely succeed.  Believe me, they don't just give you money if they don't think the result will be of some practical benefit.  ....

Alchemist #1:  I want a gazillion dollars to try to produce metallic hydrogen.  Just cuz it's cool to crush stuff at extreme pressures.  I have no idea if this will provide any benefit, but we can at least show the world we can squeeze stuff the hardest.  And it crushing machine might explode, which would be cool to see.

Alchemist #2:  I want a gazillion dollars to try to produce metallic hydrogen.  This is because I believe it will be metastable.  If so, then it will have all sorts of both practical uses and general scientific benefit.  That will make you, Highness, even richer than you already are.  While there is some debate amongst alchemists as to whether it will be metastable or not, the preponderance of the evidence leans in that direction (produces lots of papers on the subject; for you and your court magician to examine, which do indeed seem to show there's a better chance of success than failure).

Well, this may be why you fail (for the record, I have been part of various applications, from ERC grants in Europe to SBIR grants in the US) more often than not.

Tell me, how did they sell the hubble space telescope? the James webb space telescope? CERN? You think CERN was saying they'd make mini black holes for the govermnet, or antimatter? Did the James Webb space telescope say they'll propbably find a habitable planet for the government to claim?

No.

CERN allows improving physics models, testing theories, etc, which have a plethora of benefits. There's a funny situation where if the research is too direct to a commercial application, then its left to commercial investment (let the companies make the IP and the profit). That said, it is nice if you can point in the direction of a practical application.

Making metallic hydrogen would lead to improvements in many fields, it would allow refinement of quantum models, perhaps leading to improvements in the field of superconductors. It would allow us to investigate the properties of the materials deep within gas giants, leading to improvements in planetary models, it could have applications to the understanding of hydrogen at high pressures such as at the core of ICF pellets and nuclear weapons - leading to improved weapons modelling (something the government is *very* interested in)... and hey... maybe it will be metastable, which if true would be a huge payoff. You don't even have to sell it as a probable result, just a favorable risk vs reward. You risk the investment money, and the potential reward if its metastable is massive.

If you risk 100 million dollars, and there's a 30% chance it works and unlocks a several trillion dollar industry (this stuff would be awesome jet fuel, would make awesome weapons warheads, all things space become much cheaper, it could replace gasoline powered cars and lead to all sorts of zero emission vehicles... it would be an awesome fuel for a zero emission economy if its metastable and could be made en masse, with renewable energy sources or relatively clean nuclear such as Fusion or breeder reactor fission). That's a gamble I'd take every single time, even if the probability of success was only 10%.

 

You need to look beyond metastability to all the other benefits. Alchemist #1 doesn't enumerate a single one.

Alchemist #3:  I want a gazillion dollars to try to produce metallic hydrogen.  This will lead to improvements in all sorts of fields of science, allowing us to refine quantum models and save money on particle accelerators and the development of superconductors, and get better returns from the money you are already spending elsewhere on other things like planetary science. More bang for your buck! Oh, and also it might be metastable.  If so, then it will have all sorts of both commercial and military uses. The payoff would be a gazillion gazillion dollars, so the risk vs reward is worth it even if this possibility is only a gazillion to one. In fact, there is no risk because the rewards even if its not metastable are still worth it, so you can't lose! but maybe you'll also win big!

10 hours ago, Geschosskopf said:

... seem rather more difficult to solve than they are for Tokamaks, which is what everybody's betting on right now.

Actually, there's a lot of people going away from Tokomaks:

Polwell -funded by the US navy and private investors

Dense Plasma Focus - private funding and some government research funding

Stellarator - an early competitor of the Tokomak, the Tokomaks problems have led to development of these designs again, such as https://en.wikipedia.org/wiki/Wendelstein_7-X

Colliding beam Fusion/Field reversed configuration - funded by private capital

Compact Fusion Reactor - being developed by Lockheed.

IMO, the research community became overly focused on one type of reactor too early on. I can understand that they probably thought it was best to pick one design to move forward with and try to solve the problems with that particular design while also learning more about plasma physics and fusion... but in the end they didn't pick that good of a design.

Almost any of these concepts will work in theory if scaled up enough (ie ITER), but the scale and precision needed can vary considerably. No Tokomak design is even close to P-B11 fusion, whereas many of these other reactor designs are going straight there for the benefits of being aneutronic.

 

[KerikBalm]

More on metallic hydrogen stability:

https://www.quora.com/Why-might-metallic-hydrogen-be-metastable-at-room-temperatures-and-pressures

(yes, quora can be as bad as yahoo comments, but this answer has sources):

https://arxiv.org/abs/1611.02593 - " The metallic state is expected to be in the metastable long-lived state down to about 10 - 20 GPa and decays instantly at the lower pressures" For comparison, the Space shuttle external tank had its contents pressurized to about 250 kPa, so if this calculation is correct, the tank mass would need to be a lot more, as it would need to contain a pressure at least 40,000x higher. If the strength to weight ratio is fixed, that tank mass just went up 40,000x : Bye bye benefits for rocket flight.

http://jetp.ac.ru/cgi-bin/dn/e_034_06_1300.pdf - seems to imply that metallic deuterium may be more stable, and at close to absolute zero it may be stable, with the caveat "Unfortunately, one cannot state that the lifetime will be sufficiently large, by virtue of the significant difference between the metastable phase and of molecular hydrogen ..."

 

And the above, not cited by quote, just my own searching:

https://arxiv.org/abs/1709.05300

Quote

The possibility that metallic hydrogen could be recovered to ambient pressure is often attributed to papers by Brovman, although in fact they only say it would be metastable with undetermined lifetime. Density functional theory calculations presented here show that reasonable candidate structures for metallic hydrogen are wildly unstable at ambient conditions, and molecular dynamics calculations show that the lifetime to which Brovman et al refer is considerably less than a picosecond. It is concluded that the prospects of using recovered metallic hydrogen as rocket fuel or for electricity distribution may have been overstated

"may have been overstated" is an understatement...

And another forum I came across:

https://physics.stackexchange.com/questions/307832/how-likely-is-it-that-metallic-hydrogen-is-metastable-at-atmospheric-pressure

Quote

I'm not aware of any modern studies that predict solid metallic hydrogen to be stable. In general, the metastable recovery of high-pressure phases all the way back down to atmospheric pressure is very rare. The most well known exception is the graphite-to-diamond phase transition, but in that case the energy difference between those two phases is only about 0.003 eV per atom. Don't know offhand what the energy difference per atom between hydrogen gas at one atmosphere and solid metallic hydrogen is, but you can be sure that it is enormous by comparison. Not saying that metastable metallic hydrogen is impossible, but it certainly would be counter to all expectations based on past experience with high-pressure phases of various materials.

(Side Note: I work in high-pressure physics and the creation of solid metallic hydrogen has long been the "Holy Grail" of the high-pressure community. This is not the first time that someone has claimed to have created solid metallic hydrogen by static compression, and the claim is currently getting a lot of scrutiny by others in the high pressure community. BTW, fluid metallic hydrogen has been created in the laboratory using reverberating shock waves. )

Another relevant question:

https://physics.stackexchange.com/questions/308290/are-there-published-predictions-that-hydrogen-could-remain-metallic-at-ambient-p/308301#308301

Answer:

Quote

A recent NEB calculation based on DFT(see http://aip.scitation.org/doi/10.1063/1.3694793), however, showed that almost all of the currently predicted structures of metallic hydrogen are unstable at zero pressure, and there is no energy barrier between atomic phases and diatomic insulating phases of hydrogen. In addition, the conclusion of Brovman et al was based on simple approximations, and might require further scrutiny.

I don't want metallic hydrogen rockets in this game. It is using magic to keep the hydrogen so compressed, and thus its using magic for energy storage.

Energy stored in the form of matter, released by fission of fusion reactions: fine

Energy stored in the form of magically compressed material - not fine.

If this report was actually valid, and they made metallic hydrogen, the loss of the sample also suggests its not stable:

https://www.sciencealert.com/the-world-s-only-metallic-hydrogen-sample-has-disappeared

Quote

But further testing around a week ago caused the diamonds to break and the vice to fail, and the researchers haven't been able to find a trace of the metallic hydrogen since.

That doesn't necessarily mean it's been destroyed - the sample was only around 1.5 micrometres thick, and 10 micrometres in diameter - a fifth the diameter of a strand of human hair - so it's possible it's stable somewhere and missing.

But it's also a possibility that, once the pressure of the diamond vice broke, the hydrogen dissipated back into a gas, which suggests that the material isn't stable at room pressure

all the recent research seems to imply *if* they had metallic hydrogen, it didn't last once the pressure was released. That seems much more plausible than saying they just haven't found the speck in their vice after it broke.

Edited August 28, 2019 by KerikBalm

[Guest]

Oh man.

If unrealistic metallic hydrogen rockets are the biggest thing wrong with KSP2, then that'll be a very good problem to have.

[KerikBalm]

Whoop, checked the paper from a couple months ago, right there in the abstract:

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

Quote

The continuous vibron frequency shift and the electronic band gap closure down to 0.5 eV, both linearly evolving with pressure, point to the stability of the insulator C2/c-24 phase up to the metallic transition. Upon pressure release, the metallic state transforms back to the C2/c-24 phase with almost no hysteresis, hence suggesting that the metallization proceeds through a structural transformation within the molecular solid, presumably to the Cmca-12 structure.

Cool, we don't need to wait to the near future to see if its real tech or magic tech, its shown to be magic tech right now, well before the game's release.

Looking more through the paper, they mention measurements after pressure release numerous times (optical transparency, IR absorption, vibron frequency shift... it seems the next step is electrical conductivity measurements), and in all cases, they find that it is reversible, and the material reverts back to non metallic properties upon pressure release... and looking at the figures, this isn't even going from 427 GPa to ambient pressure (101 kPa), but rather down to 415-400 GPa.

If you want to store metallic hydrogen, your tanks need to be in the form of diamond anvil presses apparently...

Its a shame, it would have been cool, but it was too good to be true, like many things.

Quote

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). 

 

[KerikBalm]

23 minutes ago, Brikoleur said:

Oh man.

If unrealistic metallic hydrogen rockets are the biggest thing wrong with KSP2, then that'll be a very good problem to have.

Well, if they are in:

#1) I expect them to have similar TWR to the chemical rockets, so like 25-27:1 TWR

#2) No need to mine exotic material like He3, so its available nearly everywhere

#3) No danger to the colonies or the launchpad like a fusion rocket/orion drive

#4) An Isp greater than an LV-N... like around 1,000 Isp

So if something with the TWR of a Mainsail and the Isp of a LV-N, with readily accesible material seems fine to you in a 1-10th scale system....

 

At least after re-reading the interview, I don't think we'll actually be getting a drive like the epstein drive, just continuous thrust drives like ICF, or an Orion drive.

I hope the additional drive that they say no one has identified yet doesn't have epstein-drive like properties.

 

 

[Guest]

23 minutes ago, KerikBalm said:

So if something with the TWR of a Mainsail and the Isp of a LV-N, with readily accesible material seems fine to you in a 1-10th scale system....

First off, you've convinced me that metallic hydrogen rockets are, in fact, a bit too sci-fi for KSP. So your work hasn't been completely in vain.

Second, I still think they're close to that line and deciding on which side of the line they fall is a judgment call. As others have pointed out, KSP is sci-fi and if you think about it too hard it requires a quite a lot of suspension of disbelief; one more thing won't fundamentally change it.

Third, I do not expect them to work like you expect them to work. That would be seriously unbalancing and obsolete pretty much any other rocket engine. The devs have made games before. They know about balance issues. At this point I trust them to give them limitations that stop them from obsoleting everything. 

And finally, if they do make them that OP, it is the easiest kind of problem for us as players to live with -- simply don't design with them. So any way I look at it, from where I'm standing this is a non-problem.