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

[Xd the great]

3 minutes ago, Dragon01 said:

Yes, if it's 2500km long. Assuming 120 FPS, an object moving at c moves about 2500km per frame. You'd phase through most celestial bodies in JNSQ, nevermind stock size system. 

I don't think any of you people really realize just how fast the speed of light is. 

Time to mod.

[GluttonyReaper]

13 minutes ago, Dragon01 said:

I don't think any of you people really realize just how fast the speed of light is. 

"Quite fast."

[MechBFP]

5 hours ago, KerikBalm said:

Since KSP 2 allows thrusting in time warp

Source?

[chaos_forge]

I have to agree  I'm not so sure about metallic hydrogen. I understand, for a gameplay perspective, the dev's desire to have a engine that's a middle ground between chemical rockets and torchship drives like the Daedalus or Orion engines, but those engines are at least based on well-understood physical phenomena, while the material properties of metallic hydrogen are totally unknown.

[magnemoe]

1 hour ago, KerikBalm said:

Metallic hydrogen can also be liquid (plenty of liquid metals), but I suspect that makes it even less likely to be meta stable (remaining metalic even after pressure is released).

I could also see it being present as a suspension of grains within liquid hydrogen. Metalic hydrogen undergoing a phase change would create far too much heat (similar problem to liquid and gas core NTRs), and would need to be mixed with somethign to cool the resulting gas down to a temperature that won't melt the engine. Using water gets you pretty bad Isp, using LH2 is the best option ... so maybe you just have LH2 and metalic hydrogren grains in the tank, and keep it well mixed? Settling at the bottom while under thrust would be a problem. Maybe a dry tank with metalic hydrogen "sand" that mixes with liquid hydrogen? I dunno

Source? because they said they were putting a version of it in, so unless there is a source retracting it/clarifying that they just meant a more mundane ICF fusion drive... its wishful thinking (that I hope is turns out to be true)

MEtalic hydrogen would act like a chemical engine, and should have similar TWR, just with much better Isp. A Fusion engine (barring a thermonuclear Orion type vehicle) shouldn't have a anywhere close to a 1:1 TWR. It should be great as an engine for interplanetary and interstellar travel, but the exhaust would destroy and launch pad, and it shouldn't have the TWR to lift off of Kerbin. Orion type drives would have the TWR, but should destroy the colony if used for liftoff.

If metalic hydrogen can be made metastable at ambient pressure, it would be an amazing power source for a SSTO rocket on Earth, and for KSP2 I would imagine it being the premier engine for getting to orbit from high gravity world where you don't want to use Orion drives- or at least for taking your craft far enough away from the colony before you start ol' boom-boom.

I mean... maybe it could exist, but the point is that we don't know if its magic tech or not. We know Orion drives, Schimitar engines (ie, a rapier, but with good Isp for a chemical engine in closed cycle mode), scramjets, ramrockets, etc would work though.

We know ICF fusion could work (if scaled up enough and if there's enough precision to have uniform enough energy directed at the fuel pellet)... a Bussard ramjet may work... and I'd put it as more of a certainty than metastable metallic hydrogen, and they haven't even shown us a bussard ramjet.

Agree on metallic hydrogen. 
Also on fusion engines. Note that since trust under warp is confirmed we don't need very high TWR outside of takeoff and its nice then you do burn out of low orbit so you don't have to do multiple burns to raise Ap, still I expect higher TWR than real world ion engines simply as month long burns would be to hard to set up. 
A burn of an day on the other hand is no issues. 
Going interstellar you can ignore orbital mechanics as required speed is so much higher than orbital speed. 
 

[chaos_forge]

46 minutes ago, MechBFP said:

Source?

https://www.videogameschronicle.com/features/interviews/an-in-depth-conversation-with-the-creator-of-ksp2/

[Xurkitree]

8 hours ago, KerikBalm said:

Rask and Rusk: this system will not work right without N-body physics. I'd like to see lagarange points, I don't think this is too complicated, as simple hohmans and getting to orbit as people do normally work just fine in Principia. Principia's performance is actually quite good with KSP already, so an optimized KSP2 engine should handle it just fine. Principia's only fault as I look at it now is the user interface (can't even click on a point in the orbit and add a maneuver node)

The system will work fine for what it is under patched conics. 

The issue is that there will be too many bodies handle. You're comparing KSP stock, a system with 17 bodies, to KSP 2, with atleast 30-40 bodies. Some of them are really far away. Another thing that comes with N-body is that Jool will have to be changed, with Retro-Bop and breaking the resonance, and I'm sure most of us agree that it isn't a very nice thing to do to our system. And then each system would have to be designed with stability, not gameplay in mind. We would all have to relearn how to maneuver when we start up KSP2 and that experience could be enough to turn many of us from the game. 

And then there's the issue of n-body trajectory paths over interstellar distances... Principia is best left as a mod. At the very least, the size of the KSP file will be smaller, boosting load times.

As for magic tech, I wouldn't mind some time-save options at the end of the game to visit my colonies and stuff. I mean one of the first mods is going to be a warp drive after all...

 

Edited August 26, 2019 by Xurkitree

[nikokespprfan]

metallic hydrogen" --The entire thread

Here is an exerpt from a dev interview I translated this morning. It is English, voiced over in German, and then translated back to English. (G's why can't they just use subtitles, why does everyone need to be so proud of their language to insist on voicing it over </frustration>).

Interviewer: Can you take a closer look at new vehicle components and perhaps also new drive systems and the like?
Nate: Actually, we have an expert in drive systems. His name is Dr Uri Shumlak from the University of Washington.
And honestly you know, well I take all the blame on my own shoulders if these propulsion systems in any form should not be as 100 percent of the real target. We have done our best to ensure that these machines remain rooted in real science, even if we are only telling a story. Since I've never seen a functioning rocket with metallic hydrogen as a propulsion system at this time, of course, I can not guarantee that the same rocket in our game in any future will somehow still have something to do with real existing rockets of this kind ,
Let's stay with the metallic hydrogen technology. The point is that the metallic hydrogen actually remains stable at normal room temperature. Such a substance was only produced in the laboratory a few years ago, so this is a brand new technology. But the fact that they have been able to make a little bit of this material is enough for us to use it as a possible fuel for our Kerbal rockets. With such a fuel you could namely develop rockets that can exert twice as much thrust as conventional chemical rockets. Unfortunately, this material burns at 6000 degrees Kelvin, which causes almost any matter to melt immediately. Therefore, a major challenge is to dilute the Mettalic hydrogen so that the temperatures are not quite as high.
By the way, some of the vehicles in the trailer, especially at the beginning, the Lunar Lander Module, have exactly that drive, namely a vacuum-certified metal hydrogen propulsion system.
Well this is just the first advanced technology that you get after the normal liquid fuel rockets so there is really something you can still discover. We will certainly be able to talk more about this at another time.

https://youtu.be/ftLT_puDtxo

Edited August 26, 2019 by nikokespprfan
youtube subtitles don't tend to preserve names; fixed

[KerikBalm]

2 hours ago, Xurkitree said:

The system will work fine for what it is under patched conics. 

The issue is that there will be too many bodies handle. You're comparing KSP stock, a system with 17 bodies, to KSP 2, with atleast 30-40 bodies. Some of them are really far away. Another thing that comes with N-body is that Jool will have to be changed, with Retro-Bop and breaking the resonance, and I'm sure most of us agree that it isn't a very nice thing to do to our system. And then each system would have to be designed with stability, not gameplay in mind. We would all have to relearn how to maneuver when we start up KSP2 and that experience could be enough to turn many of us from the game. 

And then there's the issue of n-body trajectory paths over interstellar distances... Principia is best left as a mod. At the very least, the size of the KSP file will be smaller, boosting load times.

As for magic tech, I wouldn't mind some time-save options at the end of the game to visit my colonies and stuff. I mean one of the first mods is going to be a warp drive after all...

 

The system will not work fine. It already doesn't work fine in KSP, making true binaries in KSP with patched conics is wonky and doesn't work right.

A simple LOD system can solve the issues that you mention. There's no need to consider the gravity of other start systems on each other. Also I have in other threads proposed a nested SOI system with 3 body physics within each system.

3rd, you don't need a retrograde bop, that's one possible solution. I loaded principia with my own custom modded system (increased Jool surface gravity from 0.8 to 2.5 Gs to be a better Jupiter analogue, decreased the 3 major moon radius by a factor of 2/3, adjusted surface gravity), and the system is stable. Just spreading the moons out more works. There's lots of ways to make the system stable while keeping the same over all arrangement.

And FWIW, I think the first mod is more likely going to be antimatter rockets or Kopernicus for KSP2

1 hour ago, nikokespprfan said:

Here is an exerpt from a dev interview I translated this morning....

The point is that the metallic hydrogen actually remains stable at normal room temperature. Such a substance was only produced in the laboratory a few years ago, so this is a brand new technology. But the fact that they have been able to make a little bit of this material is enough for us to use it as a possible fuel for our Kerbal rockets.

 

And here's the problem. We don't know if metallic hydrogen remains stable at normal room temperature... and more importantly if it remains stable at normal room PRESSURE... which relates to the next guy I'm going to quote:

7 hours ago, Lisias said:

Of course he would report it as "habitable", that dude is a gamer designer.  He need to grasp on every possible plausible concept in order to keep some contact with the reality, otherwise the history will not stick as Science Fiction and will be tagged merely as Fantasy.

You missed the part where I said it was an analogy. As in I had a fear that he takes one thing that is speculative or not-shown-to-be-false, and reports it as true as many articles do about exoplanets - I have no problem with them including habitable planets in other systems... that can all be fictional, I don't mind, as long as its possible.

What we have here with the metallic hydrogen is the same thing... it was reported that something might be possible and now he's proceeding as if it definitely is possible.

Also, he reports it was produced a few years ago... it probably wasn't. Look on wikipedia at the history of claims that it was produced.

They may have finally produced it mere months ago:

https://www.sciencealert.com/french-scientists-believe-they-have-created-metallic-hydrogen

Quote

These results have attracted their fair share of criticism and skepticism, largely because previous claims where metallic hydrogen was said to have been created were either proven to be false or inconclusive.

In addition, this latest study has yet to be peer-reviewed and their experiment validated by other physicists

The KSP2 devs seem to be jumping the gun and not applying appropriate skepticism to avoid introducing potentially magic tech.

If they're doing this for metallic hydrogen, I fear what some of the other engines might look like.

He may have been shown this: https://iopscience.iop.org/article/10.1088/1742-6596/215/1/012194/meta

But right in the abstract should be a warning flag:

Quote

Wigner and Huntington first predicted that pressures of order 25 GPa were required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator. We discuss the applications of metastable metallic hydrogen to rocketry. 

This article should not be used as evidence that metallic hydrogen rockets are possible - Nate mentioned the site Atomic Rockets (I love that site), and that site links to this same article. This article shows what WOULD BE possible IF metallic hydrogen is metastable at low pressure. Furthermore, the difficulty in producing it, and in particular the pressures required to generate it show that the models are still missing something and can't really be trusted until they are further refined with experimental data.

Until we know IF that is the case, we don't know if metallic hydrogen rockets are magic-tech or not.

If their standard is: "you can't prove its impossible, so its not magic tech", then they've given themselves a free pass to use any magic tech they want.

Edited August 26, 2019 by KerikBalm

[TBenz]

5 minutes ago, KerikBalm said:

If their standard is: "you can't prove its impossible, so its not magic tech", then they've given themselves a free pass to use any magic tech they want.

Sounds like slippery slope fallacy to me.

They are willing to take on some speculative technology that might be impossible, but that doesn't mean they are willing to have technology that we currently know is impossible, or have no reason to believe that it might be possible. 

[MechBFP]

@KerikBalm

It’s a game, not a simulation to be used by scientists to plan the future of mankind. 

Yes it might not actually  be possible in real life, but so what? It is based on concepts/theories that at least have some remote chance of being possible.

That is completely different than things like worm holes or warp gates that would theoretically take the energy of a trillion stars to work, which is MUCH less plausible. 

Edited August 26, 2019 by MechBFP

[Guest]

I like what they've been saying about this stuff so far. Interstellar spacecraft are necessarily speculative as we've never built one and the best designs we've made are extremely early-stage. Bring on the metallic hydrogen, Daedalus, and even antimatter drive.

(Krepstein however crosses the line for me. If that's in I'm gonna pretend it's not and not use it.)

Edited August 26, 2019 by Guest

[KerikBalm]

4 minutes ago, TBenz said:

Sounds like slippery slope fallacy to me.

They are willing to take on some speculative technology that might be impossible, but that doesn't mean they are willing to have technology that we currently know is impossible, or have no reason to believe that it might be possible. 

Well warp drive could be possible if we could get out hands on negative mass. We have some reason to believe that it might be possible... so they're dealing with 2 forms of unobtainium, and gambling that 1 form of potential unobtanium isn't actually unobtanium.

[nikokespprfan]

Besides, by virtue of things being near-future technoloy, you cannt know (let me know if I'm wrong about this) if it will ever work. Take a fairly sized collection of near-future drives, such as the one in KSP2, all of which have a chance of not aging well in this way, what are the chances that any signle one of them would not age well in this way. It's drastically higher chances. Since any ne of the drives turning out to be unreal will lead to you claiming the team failed their quest, it seems an inherently bad idea to even pursue near-future drives. If they did, then people would recognize this logic and worry that some of the drives were going to be magic oooohhhhhhhhh....

Just now, KerikBalm said:

Well warp drive could be possible if we could get out hands on negative mass. We have some reason to believe that it might be possible... so they're dealing with 2 forms of unobtainium, and gambling that 1 form of potential unobtanium isn't actually unobtanium.

negative mass is very sketchy, PBS spacetime predicted many perpetual motion machines when using it, and that frankly gives me any reason to be highly skeptical of it.

 

[KerikBalm]

5 minutes ago, nikokespprfan said:

Besides, by virtue of things being near-future technoloy, you cannt know (let me know if I'm wrong about this) if it will ever work.

We know nuclear-electric drive will work.

We know an Orion drive will work.

We know ICF fusion works (what scale is needed to get excess power, and how to optimize the power output we do not know).

We know NTR will work, and can be used for atmospheric turbojets, augmented with lOx for a LANTR design, we know liquid core NTR can work.

We know air augmented rockets will work. All of these could be used for improving the options for getting from surface to orbit on a higher grav world, without needing metallic hydrogen.

 

[nikokespprfan]

22 minutes ago, KerikBalm said:

Well warp drive could be possible if we could get out hands on negative mass. We have some reason to believe that it might be possible... so they're dealing with 2 forms of unobtainium, and gambling that 1 form of potential unobtanium isn't actually unobtanium.

Also, positing that something low on the realism spectrum is somewhat realistic paves the way for me to posit that all the stuff you mentioned is high on the realism spectrum is actually somewhat unrealistic. We need the scale for ICF fusion, but who says that that scale must somehow be attainable.

 

This is not my point, that would be childish. But what kind of speculation do we allow. Where do we draw the line of magicness? When it comes to all drive that don't currently exist (maybe with exception to orion, and nuclear-electric, which have political reasons against nukes in space.), all of it is grey area. What are we willing to accept.

 

If it is indeed true that they want the metallic drive to transition to the even better drives, then I'm fine with that, even though it is a little out there.

[KerikBalm]

I don't want drives relying on negative mass for sure... but its there to illustrate the point that some model where it might be possible should not be the criteria for inclusion.

We have definitely achieved fusion via ICF. We have even achieved fusion through ICF where the pellet fusion released more energy than was put into it! (ie, the light energy hitting it, ignoring the inefficiency of the lasers). Teller-Ullam designs could be said to be ICF fusion as well. We know the reaction works, we know the fuel exists, we know there are ways of getting the reaction to occur.

We may have achieved metallic hydrogen, but we definitely have not achieved metallic hydrogen at low pressure.

We've built ram-rockets and nuclear ramjets... so those things are confirmed realistic.

 

As I said in the title, I am concerned that they are going to far into the speculative realm. I'm not saying they are definitely wrong, but I see worrying signs.

[nikokespprfan]

11 minutes ago, KerikBalm said:

As I said in the title, I am concerned that they are going to far into the speculative realm. I'm not saying they are definitely wrong, but I see worrying signs.

Ok fair.

[magnemoe]

29 minutes ago, KerikBalm said:

The system will not work fine. It already doesn't work fine in KSP, making true binaries in KSP with patched conics is wonky and doesn't work right.

A simple LOD system can solve the issues that you mention. There's no need to consider the gravity of other start systems on each other. Also I have in other threads proposed a nested SOI system with 3 body physics within each system.

3rd, you don't need a retrograde bop, that's one possible solution. I loaded principia with my own custom modded system (increased Jool surface gravity from 0.8 to 2.5 Gs to be a better Jupiter analogue, decreased the 3 major moon radius by a factor of 2/3, adjusted surface gravity), and the system is stable. Just spreading the moons out more works. There's lots of ways to make the system stable while keeping the same over all arrangement.

And FWIW, I think the first mod is more likely going to be antimatter rockets or Kopernicus for KSP2

Even if KSP2 uses n-body physic it will only affect ships and asteroids, planets and moons would be on rails. n-body would use pretty strict LOD rules.
And lower orbits are not affected this includes GEO on Kerbin,
Imagine you have an base in Laythe orbit who is no gone during an interstellar mission, this is an bug. 
Yes stuff like Duna polar orbits well outside of Ike might not be reliable, however we are used to stages dropped halfway to Minmus end up in solar orbit because of the Mun

[Lisias]

54 minutes ago, KerikBalm said:

You missed the part where I said it was an analogy. As in I had a fear that he takes one thing that is speculative or not-shown-to-be-false, and reports it as true as many articles do about exoplanets - I have no problem with them including habitable planets in other systems... that can all be fictional, I don't mind, as long as its possible.

No, I didn't. What you did was more analog to criticizing Contact from Carl Sagan because it wasn't Cosmos.

KSP is a game. A Science Fiction game, to be more exact. We are kicking green butts into orbit on a fictional planet somewhat bigger than a moon, besides having the gravity of a full planet - not to mention having an atmosphere with the consistence of mocotó broth using a myriad of different engines running on "fuel" no matter what (not to mention jets that work under water).

 

[Guest]

Keep in mind also that "too far" is a subjective judgment call. Yours might be different than mine, yet both might be legitimate. Different players look for somewhat different things in KSP.

[captinjoehenry]

Honestly I don't mind metalic hydrogen.  It gives a good middle ground gameplay wise and it is something that is at least well theorized.  Admittedly it's not yet proven to be possible or even fully understood but it fits very well with the gameplay and is at least passingly realistic.  Personally I would have issues with an Epstein drive being in the game due to how blatantly unrealistic it is.  As the problem with the epstein drive comes from the very nature of the drive with how much energy it needs to be producing to have so much thrust and exhaust velocity.  While at least for metallic hydrogen all it needs to worry about is whether or not the fuel is really possible.  It seems to be in some tests and that's more or less good enough for me considering it's gameplay role.  While the epstein drive is scientifically impossible.

[chaos_forge]

5 minutes ago, captinjoehenry said:

Honestly I don't mind metalic hydrogen.  It gives a good middle ground gameplay wise and it is something that is at least well theorized.  Admittedly it's not yet proven to be possible or even fully understood but it fits very well with the gameplay and is at least passingly realistic.  Personally I would have issues with an Epstein drive being in the game due to how blatantly unrealistic it is.  As the problem with the epstein drive comes from the very nature of the drive with how much energy it needs to be producing to have so much thrust and exhaust velocity.  While at least for metallic hydrogen all it needs to worry about is whether or not the fuel is really possible.  It seems to be in some tests and that's more or less good enough for me considering it's gameplay role.  While the epstein drive is scientifically impossible.

It's not well theorized at all. Materials science is notoriously difficult to make theoretical predictions about, and the theorized meta-stability of metallic hydrogen is tentative at best. Compare this to fission or even fusion engines where the fuels and energy production processes are extremely well understood. Building an Orion or Daedalus drive is an engineering problem. Building a metallic hydrogen rocket is a science problem.

The Epstein drive is at least within the bounds of the amount of energy fusion releases, just unreasonably efficient. "More efficient than it should be" is WAY more realistic than a rocket based on a substance that might not even exist. I don't see how you consider a drive that requires unobtanium to function realistic at all. By that measure, we may as well say wormholes or warp drives are realistic, since we know exactly how they'd work if we could just get some negative mass-energy to fuel them. Plus the Casimir effect has demonstrated negative mass-energy, so it's theoretically possible!

Honestly, if we're going for completely speculative drives, I'd prefer antimatter rockets. At least we know for sure that antimatter exists.

[magnemoe]

16 minutes ago, KerikBalm said:

I don't want drives relying on negative mass for sure... but its there to illustrate the point that some model where it might be possible should not be the criteria for inclusion.

We have definitely achieved fusion via ICF. We have even achieved fusion through ICF where the pellet fusion released more energy than was put into it! (ie, the light energy hitting it, ignoring the inefficiency of the lasers). Teller-Ullam designs could be said to be ICF fusion as well. We know the reaction works, we know the fuel exists, we know there are ways of getting the reaction to occur.

We may have achieved metallic hydrogen, but we definitely have not achieved metallic hydrogen at low pressure.

We've built ram-rockets and nuclear ramjets... so those things are confirmed realistic.

 

As I said in the title, I am concerned that they are going to far into the speculative realm. I'm not saying they are definitely wrong, but I see worrying signs.

Yes its realistic fusion rocket designs under development now, however they need an external power source as they produce less energy than they produce who is nothing. However the fusion significantly increase the ISP of the engine over an vasmir with the same power input. 

And yes they could make an Easter egg engine finding an alien relic on an super earth orbiting close to an neutron star or an black hole. 
No the system has no other resources outside a few cupeier belt objects. 
Then you have to return it to Kerbin for research.
Now add radiation so you can not orbit the planet, you have to do direct decent on the backside. 
 

[Randox]

To enable intersellar travel, even in a scaled down universe (and frankly, it's not that scaled down if the distance is ~2 ly), we're going to have to encroach on fiction and torch drives. At least, we are if the goal is to have an endgame where you are setting up self supporting bases and building ships in another star system on a timescale that isn't getting into generational ship territory. But I get your point.

 

I have to be on board with Metallic Hydrogen though. Yes, the current signs point to it either not being possible at all, or not being viable with known projected technology. But...it's also really cool, and something that would be absolutely amazing if it were real because it would be both massively useful, and not an existential crisis. Metallic Hydrogen doesn't lean so directly to building an actual torch ship, and by extension, doesn't readily turn into a weapon that can destroy entire planets by running into them. I can see something that probably isn't possible would be an issue...but I think I have to side with the rule of cool on this one. Besides, if we don't include it in a game now, it might be disproven before we have another chance

 

I do feel like concessions to gameplay are going to need to be made, and while I would like things to be grounded in good existing and speculative science, I also have a day job and would like to see myself building ships on planets in another star system sometime before the year 2025.