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

[Xd the great]

9 minutes ago, nejc said:

When it comes to propulsion, my vote goes against speculative science, but still in favor of speculative engineering.

Therefore, I am in favor of confinement fusion and antimatter rockets. However, not in favor of low pressure metallic hydrogen and Alcubierre drive.

Agree on speculative science.

Antimatter drives should be for low thrust satellites. Very low thrust, perhaps lower than an ion drive.

What about high pressure metallic hydrogen that has a lot of thrust and ISP, but is sensitive to collision, heavy, and overheating?

[KerikBalm]

7 minutes ago, Xd the great said:

What about high pressure metallic hydrogen that has a lot of thrust and ISP, but is sensitive to collision, heavy, and overheating?

No, what we've seen so far requires a pressure 1,640,000x higher than the ET of the space shuttle to keep it metallic at -193 C.

If the mass scales linearly with tank pressure, then we've got a very very very very terrible fuel fraction for our tanks, and NTR level ISP makes it worthless.

High pressure metallic hydrogen won't work barring some super exotic material to have a reasonable tank fuel fraction, and low pressure metallic hydrogen requires magic.

[nejc]

56 minutes ago, Xd the great said:

Antimatter drives should be for low thrust satellites. Very low thrust, perhaps lower than an ion drive.

As far as I'm aware, even antimatter torchship is only in the realm of speculative engineering. Among other things, It might require a space-based particle accelerator that circumvents the entire planet to produce tonnes of antimatter, so it is super-duper speculative engineering, but no yet identified changes to science text books needed. Correct me if I am wrong.

56 minutes ago, Xd the great said:

What about high pressure metallic hydrogen that has a lot of thrust and ISP, but is sensitive to collision, heavy, and overheating?

That just replaces one unobtainium - low pressure metallic hydrogen - with another - some material that can support planetary scale pressure whilst being lightweight. So still speculative science.

Edited August 29, 2019 by nejc

[Xd the great]

1 hour ago, KerikBalm said:

No, what we've seen so far requires a pressure 1,640,000x higher than the ET of the space shuttle to keep it metallic at -193 C.

If the mass scales linearly with tank pressure, then we've got a very very very very terrible fuel fraction for our tanks, and NTR level ISP makes it worthless.

High pressure metallic hydrogen won't work barring some super exotic material to have a reasonable tank fuel fraction, and low pressure metallic hydrogen requires magic.

But diamond can handle that pressure right?

Super duper expensive though.

50 minutes ago, nejc said:

As far as I'm aware, even antimatter torchship is only in the realm of speculative engineering. Among other things, It might require a space-based particle accelerator that circumvents the entire planet to produce tonnes of antimatter, so it is super-duper speculative engineering, but no yet identified changes to science text books needed. Correct me if I am wrong.

Yeah, it is engineering fiction, exactly why it should be low thrust weight ratio.

[nejc]

16 minutes ago, Xd the great said:

But diamond can handle that pressure right?

Super duper expensive though.

It would be 'thousands' of tonnes of diamond per tonne of hydrogen. Hence, not lightweight. This would eat away the benefit of metallic hydrogen as the ship would be more efficient by just getting rid of such a gigantic diamond fuel tank and replacing metallic hydrogen with kerosene.

16 minutes ago, Xd the great said:

Yeah, it is engineering fiction, exactly why it should be low thrust weight ratio.

My point was that I am in favor of speculative engineering, but not in favor of speculative science. Otherwise forget about moar boosters.

Edited August 29, 2019 by nejc

[KerikBalm]

Also note the difference between tension and compression. Diamond can handle the pressure on the interior wall, but it doesn't have great tensile strength, and a tank at 415 GPa is going to explode unless there is something with amazing tensile strength around it, or the tank is very very massive to spread the load out, with pressure decreasing as one gets farther from the metallic hydrogen.

Soo... like maybe a diamond inlaid container wrapped in carbon nanontubes?.. just checked, they have a tensile strength of 11-63  GPa.

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

That tank is coming apart unless its walls are really thick.

[Xd the great]

11 minutes ago, KerikBalm said:

Soo... like maybe a diamond inlaid container wrapped in carbon nanontubes?.. just checked, they have a tensile strength of 11-63  GPa.

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

That tank is coming apart unless its walls are really thick.

How much diamond is needed in how much carbon nanotube?

Yep, this should be a mod, not a stock feature.

[nejc]

4 minutes ago, Xd the great said:

How much diamond is needed in how much carbon nanotube?

Enough to hold near Jupiter core level pressure. 'Mariana Trench squared'

Edited August 29, 2019 by nejc

[KerikBalm]

I mean... heck, at that point, just give us space elevators and ignore the need for metallic hydrogen for a high thrust rocket to take off from planetary surfaces

[nejc]

2 minutes ago, KerikBalm said:

I mean... heck, at that point, just give us space elevators and ignore the need for metallic hydrogen for a high thrust rocket to take off from planetary surfaces

And if we can construct that, maybe we can construct a large particle accelerator in GEO to produce antimatter. No metallic hydrogen needed.

But, this is just dreaming at this point. The development is already set for metallic hydrogen.

[Xd the great]

8 minutes ago, nejc said:

And if we can construct that, maybe we can construct a large particle accelerator in GEO to produce antimatter. No metallic hydrogen needed.

But, this is just dreaming at this point. The development is already set for metallic hydrogen.

What about other metallic "non-metals"?

[nejc]

17 minutes ago, Xd the great said:

What about other metallic "non-metals"?

Never heard of a concept for such propulsion so I consider it even more speculative. As far as I'm aware, they have the same temperature, pressure hurdles.

[KerikBalm]

43 minutes ago, nejc said:

But, this is just dreaming at this point. The development is already set for metallic hydrogen.

Yea, which is why I'm worried.

If they put this magic tech in while confidently stating its real and metallic hydrogen stays metallic when pressure is realesed, and they've only revealed 3 new engines (with enough details to identify them), and 1 is magic while another (ICF) is an engineering nightmare, and the frigging Orion drive is the most reasonable of the revealed drives, I think it is cause for concern

[Xurkitree]

1 minute ago, KerikBalm said:

Yea, which is why I'm worried.

If they put this magic tech in while confidently stating its real and metallic hydrogen stays metallic when pressure is realesed, and they've only revealed 3 new engines (with enough details to identify them), and 1 is magic while another (ICF) is an engineering nightmare, and the frigging Orion drive is the most reasonable of the revealed drives, I think it is cause for concern

Really? You're worried about this? 

[nejc]

1 hour ago, KerikBalm said:

Yea, which is why I'm worried.

If they put this magic tech in while confidently stating its real and metallic hydrogen stays metallic when pressure is realesed, and they've only revealed 3 new engines (with enough details to identify them), and 1 is magic while another (ICF) is an engineering nightmare, and the frigging Orion drive is the most reasonable of the revealed drives, I think it is cause for concern

I don't necessarily see a problem with ICF. Ridiculous numbers of boosters stacked together in KSP1 would also be an engineering nightmare. Only shrapnel would reach orbit with such designs. But that is the sentiment of KSP. I don’t mind overblown engineering. Just stick to real science when it comes to propulsion. So I'm not too worried, I just hope that metallic hydrogen can be ignored on the tech tree (unlikely). 

[linuxgurugamer]

1 hour ago, KerikBalm said:

Yea, which is why I'm worried.

If they put this magic tech in while confidently stating its real and metallic hydrogen stays metallic when pressure is realesed, and they've only revealed 3 new engines (with enough details to identify them), and 1 is magic while another (ICF) is an engineering nightmare, and the frigging Orion drive is the most reasonable of the revealed drives, I think it is cause for concern

The fact that they only revealed 3 new drives doesn't mean there isn't more which was just not ready to be released

[KerikBalm]

6 hours ago, nejc said:

When it comes to propulsion, my vote goes against speculative science, but still in favor of speculative engineering.

Therefore, I am in favor of confinement fusion and antimatter rockets. However, not in favor of low pressure metallic hydrogen and Alcubierre drive.

That's fairly  well put, I'll agree to that standard.

Speculative engineering involving established science = fine

Speculative science = not fine

 As you see in the start of the thread, I was defending ICF, because the science behind it is sound. That also works towards the colony stuff.

4 hours ago, Xd the great said:

How much diamond is needed in how much carbon nanotube?

Yep, this should be a mod, not a stock feature.

So I started doing these calculations. carbon will form diamond at 3.5 GPa. It seems you need about 415 Gpa for metallic hydrogen. So if using carbon nanotubes to contain the pressure (the tank is under pressure, so you need high tensile strength), the pressure at the outside of the diamond layer needs to be 415/3.5 = 118.6x lower.

Pressure will decrease with r^2 (or rather, surface area does, and the force is distributed over the surface area), this means the radius of the outer diamond layer will need to be about 10x the radius of the interior metallic hydrogen wall. Volume is a r^3 law, so the total diamond volume will be roughly 1000x that of the tank interior

I looked at this link: https://www.sciencedirect.com/topics/physics-and-astronomy/metallic-hydrogen

Metallic hydrogen may have a density of 10 g/cm^3. Diamond's density is 3.51 g/cm^3.

1000*3.5= 3500, compare to 1*10. The diamond alone (assuming use of carbon nanotubes) is 350x the mass of the metallic hydrogen carried. We havent yet considered nanotube mass, but I suspect its not significant at this point.

Maybe you can use a material with a lower tensile strength that can withstand higher pressures to bring tank mass down... but its clear that the tank mass will be so high that even with an Isp of 1700s (melts the engine, 1000s is more reasonable), its not worth it.

1 hour ago, linuxgurugamer said:

The fact that they only revealed 3 new drives doesn't mean there isn't more which was just not ready to be released

Oh, I'm not saying there's only 3. I know there are more, we've seen pics of others, but not enough information has been released to identify the operating principle with certainty.

I'm just saying from the small sample size, we only have 1 of 3 that will certainly work (2 of 3 probably will work). If they have 30 new drives, does that mean only 10 will certainly work? (no, it doesn't mean that, the sample size is too small), but I also doubt we'll have 28 that will certainly work, 29 that will certainly or probably, and only 1 that wont... see what I'm getting at?

[linuxgurugamer]

2 minutes ago, KerikBalm said:

I'm just saying from the small sample size, we only have 1 of 3 that will certainly work (2 of 3 probably will work). If they have 30 new drives, does that mean only 10 will certainly work? (no, it doesn't mean that, the sample size is too small), but I also doubt we'll have 28 that will certainly work, 29 that will certainly or probably, and only 1 that wont... see what I'm getting at?

No.

It's a game, based on science, but not married to it.  If it was, then Kerbals themselves wouldn't exist.

In all genre's, there is a little bit of hand waving.  In all other space-based games, there is a lot of hand-waving (pay no attention to the man behind the curtain).  In KSP, there is as little as possible, which doesn't excludes it entirely.

You are certainly welcome to only use those part which you feel will work in real life.  But they are there for game balance, etc

 

[KerikBalm]

I will certainly be skipping metallic hydrogen engines

[chaos_forge]

11 hours ago, KerikBalm said:

Scott manley shares my same concerns about the binary planets, and some of the other planets/ bodies...

https://www.twitch.tv/videos/473822143?t=38m14s

At 38:15: Its putting Scott Manley off too. He thinks they have no solution to the binary planet problem. Then they go into Ice on Minmus, and a volcanic Pol... neither of which make sense...

It also appears that the devs had no idea that there are gimballed SRBs...

In the stream, Scott also mentions that the devs said they had no plans of implementing n-body, and that it seemed like they hadn't really thought about how the binary planet would work, so:

23 hours ago, Dragon01 said:

You're all assuming KSP2 devs know what they're doing. I'm not entirely convinced this is the case.

20 hours ago, TBenz said:

Maybe I've bee following Star Citizen for too long, but I tend towards the lowest possible expectations. 

It seems y'all are right, and I have to eat my words. I'll have to remember to have less faith in game devs in the future. They're in touch with Scott Manley so hopefully he'll be able to stop them from trying to implement some weird hack-job SOI system, but I fear their solution will be to just scrap their plans for binary planets instead of implementing n-body.

I still think n-body would be good to include in the stock game, because the main problems players could have with it could be easily done away with by implementing automatic/abstracted-away station-keeping (which is pretty easy to do),  and by having a good UI, which is one of the few things I think professional game devs can do much better than modders.

Anyways, with regards to metallic hydrogen:

7 hours ago, nejc said:

When it comes to propulsion, my vote goes against speculative science, but still in favor of speculative engineering.

This is also where I'm at. As long as it's know to be theoretically possible within our current knowledge of physics, I'm okay with abstracting away the engineering challenges. What I'm less okay with is abstracting away the science.

Edited August 29, 2019 by chaos_forge

[ThatGuyWithALongUsername]

To be fair, they started working on this long before the 2019 paper, and, well, we don't know how trustworthy that is. It isn't science if you can't replicate results. So we can't  really say for 1000% certain that it isn't metastable.

And pretty much everything else you're complaining about I'm not really worried about. They get the "feel" of KSP, they get the need for a balance between realism and gameplay, and they are sticking to realistic possible future technologies. Of course not current technology, if we had the technology for interstellar travel then we would have done that or at least tried to before budget cuts or anything. Metallic hydrogen is really the only possibly iffy thing here, and even that we may need more research in real life to figure that out.

[Guest]

The problem with KSP is, it's an educational game, with a potential for making science appeal to a wide group of people who didn't really care much about it before. I see this as a responsibility of sorts. If you include MetH2, you may end up spreading a persistent misconception that it really works, even if it turns out it doesn't. IMO, KSP really should stick to real science, because for many people, it's kind of a "gateway drug" to hard SF. Far-fetched engineering is all right (it's all on the "we'll get there eventually" level), but science should be kept real.

I told Nertea to drop that blasted thing... See what you get for not listening to me.  

[Geschosskopf]

16 hours ago, Brikoleur said:

So I think that in theory a city-scale self-sustaining Martian colony of genetically engineered post-humans could be possible. In practice I think it's vanishingly unlikely. IOW I don't think it's quite "magic," sitting just barely on this side of that line.

Yeah, I thought about 3D printing and tried to list some essentials I doubt that can ever make.  But even if it can someday, the inputs to 3D printers are themselves the products of long, complex industrial processes, so 3D printing just slightly shifts the problem of needing a huge industrial base, it doesn't eliminate it.  Without that base, you'd still have to truck in resupplies of 3D printer ammo.  Plus, 3D printing is SLOW compared to conventional manufacturing techniques.  I think it's already about as fast as it can go, as the previous bit of material cools just enough to take the weight of the next bit without deforming.  This makes it unsuitable for mass-producing highly consumable items.  It's more for durable goods or things you don't need many of.

As to modifying ourselves, that's definitely going to go ahead full speed whether we like it or not.  Not just genes but implanted machinery of all sorts.  There are too many rich guys who want to live forever who will make this happen regardless of legality, and there are enough poor people who think it's cool to get the laws changed in hopes the tech trickles down to them eventually.  So eventually, we'll become the Borg.  Or even better, just pure machinery without all the messy organic luggage.  This whole thing would solve a lot of problems all along the way to completion so I see it as a desirable outcome in general.

I personally have no desire to live forever.  Or even more than my 3 score and 10, if that long.  I didn't ask to be here and in general, life sucks for the vast bulk of people the vast bulk of the time, so I see no reason to hang around any longer than necessary.  I've flatlined a few times and it's not so bad, so I don't fear the darkness.  But that's just me.   If somebody else wants to turn us into the Borg, and that ends up making things suck a lot less for a lot more people, go for it  

 

15 hours ago, KerikBalm said:

They mentioned manufacturing in space too, so a VAB function doesn't mean self sufficient necessarily (I hope not, for the orbital construction). If you need to send parts and resources to space to build rockets there, I'm fine with that. Assembly of pre-built components in orbit is more realistic than doing all the steps from ores to ships...

Yeah, this is something we need more info about.

My own thinking about the necessity of self-sufficiency for life support is that otherwise, it's micromanagement Hell.  There is no middle ground.  Either you don't have to worry about it at all (in which case, the whole system is pointless overhead), or you have to worry about it too much, at the expense of doing basically anything else.  That has always been my personal experience with using all the LS mods (except Kerbalism) for many years, which is why I've recently decided the whole thing is counterproductive and have stopped using LS.  I gave it a VERY good and thorough evaluation and I believe my conclusions are inescapable  

The only real variable that matters for a life support mechanic is how frequently you have to interact with it (by whatever means) to prevent disaster.  If disasters can't ever occur, then LS is a complete waste of time, effort, and CPU cycles.  Might as well not have it and get better FPS.  So, for this discussion, we assume Kerbals will die unless the player makes periodic inputs to the LS system.  But the more often the player has to make such inputs, the more the system is just annoying micromanagement, the less it's an interesting game mechanic, and the less other things the player can do in the limited interval of realtime the player has to indulge in KSP.  And no matter what timescale you set the periodic inputs on, it will ALWAYS be too often at some point in the game, and so infrequent at others as to be utterly pointless.

Consider this situation...  You have configured your LS system so it only needs input once per game year.  But you've got a ship that will be 20 years on passage to some distant location, and that's really all you care about right now.  No other pressing business, so you just want to warp ahead 20 years to play the arrival of this ship.  But you can't.  You can warp ahead no more than 1 year at a time, fiddle with LS somewhere, repeat.  20 times minimum during the passage.  More if you have several colonies/bases/long-term ships and their intervals of needing tweaking aren't in sync (which they probably won't be).  So maybe 50-60 such interruptions during the trip.  Each time you have to fiddle with LS, you have to go to 1:1 time, switch to the colony/base/ship that needs tweaking, and do what needs doing (which might involve flying a whole inter-moon trip to truck in some supplies from elsewhere).  So lots of real time goes by without much game time elapsing, meaning your 20-year ship makes very little progress.  This is similar to, but WAY worse, than having to deal with all the spam messages from deployed science in BG. 

The only way to avoid this problem is to increase the LS tweaking interval to the point that it never interrupts anything, which is the same as saying everything is self-sufficient, which makes the whole LS system a total waste.  Which is why life support SHOULD NEVER BE STOCK (although it appears I've lost that argument).

So getting back to orbital shipyards.....

Obviously, something in orbit can't sponge up any resource other than sunlight.  Everything else it needs has to trucked in.  But (in most mods where you have more resources than just Ore), the same also goes for surface bases/colonies.  You NEVER have all the resources you need right under the colony so you ALWAYS have to truck in the rest from elsewhere.  Unless this process is automated (some mods support this to varying degrees), you have to take time out from your warping to do this trucking.

So it seems to me that the least detrimentally impactful way to do any of this is to automate it all.  Making a colony self-sufficient for LS means putting it where it can get all the resources it needs.  If not all those resources are available on-site, add modules to the colony that automate harvesting and transporting the remaining resources.  If you have that sort of system, then it should be no problem extending it to orbital colonies.  They just need more resource-acquisition modules, or be near a surface colony that has such modules, plus another to export resources to the orbital station.

Seriously, I'd MUCH rather have such automation than have to do all this menial labor myself when I have bigger fish to fry.  My colony has a population of minions.  I'm paying them (in food and air, at least) to do my bidding.  So they'd better earn their paychecks and be productive when I'm not looking over their shoulders.  Which is realistic.  The whole idea of Kerbals standing completely still unless "The Spirit (me) moves them" just doesn't cut it in today's economy  

[sh1pman]

3 hours ago, Dragon01 said:

The problem with KSP is, it's an educational game, with a potential for making science appeal to a wide group of people who didn't really care much about it before. I see this as a responsibility of sorts. If you include MetH2, you may end up spreading a persistent misconception that it really works, even if it turns out it doesn't. IMO, KSP really should stick to real science, because for many people, it's kind of a "gateway drug" to hard SF. Far-fetched engineering is all right (it's all on the "we'll get there eventually" level), but science should be kept real.

But it applies to every sci-fi setting ever created. We don’t know if these things work or not, because we don’t have them yet. If we had, it it wouldn’t be sci-fi. Devs can’t see the future, so if there’s going to be any kind of future tech in KSP2, there will be a lot of guessing and assumptions involved. And I’d like it to have some future tech, that’s why I’m fine with metallic H2 engine. It’s clearly more realistic than, say, Mystery Goo, and I’ve never seen anyone having problems with that substance being in KSP. 

[Guest]

29 minutes ago, sh1pman said:

But it applies to every sci-fi setting ever created. We don’t know if these things work or not, because we don’t have them yet. If we had, it it wouldn’t be sci-fi. Devs can’t see the future, so if there’s going to be any kind of future tech in KSP2, there will be a lot of guessing and assumptions involved. And I’d like it to have some future tech, that’s why I’m fine with metallic H2 engine. It’s clearly more realistic than, say, Mystery Goo, and I’ve never seen anyone having problems with that substance being in KSP. 

No it doesn't. I don't know if you noticed, but most other sci-fi does not purport to be educational (and those that do better have their facts straight!). Everyone knows things don't work in reality they way do in Star Wars. KSP, however, had presented itself as more than a mere SF game, but a simulator that allows young people to learn about how space really works. KSP1 is great at this, despite some shortcomings. Most drives in KSP2 have very firm grounding in physics, even if they are far fetched engineering wise. Orion, all those fusion drives, even the NSWR have all been proposed in serious scientific papers. Metallic hydrogen is based on a hypothesis that's now pretty much disproven. It's pure fantasy, but KSP2 will be going around telling people that it works. 

Aside from the fact Mystery Goo is clearly silly, it is, ultimately, not "wrong" in how it works. You observe it and you learn something. We don't know what it is, but that's why we're observing it, and that's a perfectly scientific approach. I wish they had done detailed, real-world experiments like DMagic did, but the Mystery Goo doesn't really teach anything incorrect. It fails to teach about science that is actually done in space, but that's more in the "wasted opportunity" category than teaching people wrong things. I'd replace it with a particle physics payload in a heartbeat (or a materials science experiment), it'd work exactly the same (owing to KSP's limited science system), but at least the messages would hint at some actual science instead of lolsokerbal.

Edited August 30, 2019 by Guest