Bingleberry

You said: That’s wrong, it’s hydrogen that behaves like a metal, as such “metallic,” it is not “a metal.” Metals have very specifically described properties, like filled electron shells (why one electron in hydrogen is an important aspect), and huge valence bands, because they typically have multiple valence electrons that are far from the nucleus (hydrogen has one that is adjacent to the nucleus)... the ionization energy of hydrogen needs to be exceeded for a valence band to appear. I stated it is essentially highly compressed plasma, you said “no,” I gave you a paper that says one must pass the plasma phase transition to get metallic hydrogen... are you saying my peer reviewed paper is not relevant because it conflicts with your opinion? As stated above, you say in no uncertain terms “[metallic hydrogen] is a metal,” I was pointing out that it is not a metal from a materials standpoint, it is a metal from a conductivity standpoint... so above, no filled electron shells, no large valence bands, etc... admittedly, my example could have used some work, but again, you state a non-metal is a metal... that is an unequivocally incorrect statement. If one is defining a “metal” the number of electrons is important... again, see above... it has metallic behavior, not a metal... is metallic iodine a metal? No, it is iodine that has been forced into a metallic-like behavior. Chemistry is, literally, a study of how electrons move, because all bonds are dictated by valence electrons... don’t ask a chemist “why does it matter how many electrons it has in total.” Because it ALWAYS matters... you’ve clearly never taken any courses in organic, inorganic, p-chem, etc, because you’d never make such an obtuse statement. What pressure do you think exists in the exhaust nozzle of a theoretical metallic hydrogen engine? I have a hard time thinking it is “low” by any measure, and orders of magnitude higher than the paper you presented. That said, if metallic hydrogen passes a plasma transition, what do you think it is before it transitions to atomic hydrogen?

@KerikBalm pressure literally ionizes hydrogen: https://arxiv.org/pdf/astro-ph/9909168.pdf even at low temperatures: https://iopscience.iop.org/article/10.1088/0963-0252/12/4/027/pdf https://iopscience.iop.org/article/10.1088/0370-1328/79/4/308/pdf The transition to a hydrogen metallic state is literally called the “plasma phase transition”: https://www.pnas.org/content/pnas/107/29/12799.full.pdf

The first citation calculates in stellar atmospheric densities (less than one mole per cubic meter, n=10^20 /m^3), which would be orders of magnitude smaller than anything in a theoretical metallic hydrogen containment system (1 mole of hydrogen, at STP is 0.0224 m^3)... because you sure don’t need 10000 k to make room temperature hydrogen plasma... the second citation makes it sound almost as “magical” as a warp drive (from a containment and manufacturing perspective)

Actually, that is wrong... hydrogen has 1 proton, if the electron is freely moving in a soup, the interaction between attractive species is negligible, this is ionization. All you need is to remove 1 electron from xenon, and it’s an ion... I am not sure what you’re trying to argue here... xenon plasma is Xe1+, it’s not a bald nuclei... by definition, you are creating ionized xenon gas by removing an individual electron... once you start boiling off inner electrons you start making x-ray emitters... also, yes, passing a charge through metal ionizes the free flowing, loosely held outer electrons, they are just quickly replacing the electrons behind them in a flow... if you keep the metal in a vacuum, pass a charge through it, and put a grounding plate on the other side of the metal, you get a cathode ray, these are electrons that are ionized off of the metal. The free flow of electrons, in a metal, is different because these electrons are outer (loosely held) electrons... these electrons are unpaired and very far from the nucleus... while the hydrogen electron is unpaired, it is as close to the nucleus as you can get. While metallic hydrogen might not be plasma, per se, if those electrons are not interacting with the proton in an attractive nature, that would be an ionized state... there’s just too much energy in the system. Also, when I said “not ductile,” I was referring to its state of matter... as I can tell, it THEORETICALLY forms a liquid/slush, I never said liquids couldn’t be metals, I was stating it is not a solid. I am, conductive polymers are conjugated polymers... since we have a cloud of electrons over the length of the polymer, you’d expect it to automatically be conductive, because it is like a wire... a cloud of electrons freely flowing over the length of the conjugated and catenized carbon atoms (and sometime nitrogen/sulfur/etc) looks like a linear piece of metal... but you can’t conduct unless you put a dopant in the material, allowing something to easily contribute an electron to start the flow (or a positive charged “hole”), because those pi-bond electrons are just too tightly held. Just because you have a soup of flowing electrons, like phenyl rings, it does not mean that these clouds of electrons are changing the overall charge of the particle, and would allow for metallic conduction... the whole “sea of electrons” theory of metal has been around since before I was in high school, but the “sea of electrons” is a function of the fact that these OUTER electrons are so loosely held, not because they behave as a wave and/or particle... they behave like a liquid, flowing amongst a lattice of nuclei. The outer electrons of metals have weak attraction, and can easily be ionized, just look at the photoelectric effect on most metals... you can’t get a hydrogen’s electron to “flow” without tearing it off of the nucleus first.

I don’t know, everybody in this forum rags on simplerockets, and even the tablet version gives you propellant options... I mean, if the kerbals are going to be capable of interstellar travel, shouldn’t they be able to optimize fuels for Eve-ASL flight?

For those saying it’ll be “too complex” ignore that there are solutions for this... first, they can set the option in an “advanced tweakables” section, and let those that care about it to activate it. Second, you can make it a basic choice, for example I choose engine x, the game asks “where do you plan on using it?” The player sets it to Kerbin-ASL, or vacuum, or duna-upper atmosphere, and the game “chooses” the fuel with the best isp for the given scenario. You can add various fuels, without burdening the player about its particular energy density at a given atmosphere (or lack thereof). Also, somebody said “leave it to the modders,” that seems unreasonable to those of us that play console and can’t get any mods... I would love to see advanced life support.

Its a metal, not a plasma. After the phase change, it would not even be a plasma (but it would be really hot, but not hot enough to ionize monatomic hydrogen) If it’s conductive, than the electrons are free flowing... since a hydrogen atom has one electron, if said electron flows from said hydrogen atom, it must necessarily be ionized... the ionization energy of hydrogen is about 14 eV, which is way lower than the energy involved in generating the metallic hydrogen. Also, it’s metal from a conductivity standpoint, not a material-chemistry standpoint. As I’ve read, it’s not a solid, it behaves more like a liquid than a solid. The “metallic” only refers to the fact that it conducts, not because it is a ductile solid. Edit: I’m a biochemist, so my knowledge of physical chemistry ended with my last p-chem class in grad school... too much calculus! So, I am by no means an expert in this, I am just trying to rationalize why this might work

Perhaps you were struck by two different krakens? It’s definitely weird that your RCS was on, but you appeared to be locked in space

@KerikBalm I appreciate the explanation... best I can tell is metallic hydrogen is essentially highly compressed hydrogen plasma, so it seems it really depends on the atmosphere it is discharged in. That said, I don’t know how much energy might be released upon expansion, but can we reasonably say that it would be capable of breaking a CO double bond and getting energy out? Or are we just talking about using the vent pressure to generate thrust? Because the energy output of forming an H to H bond is pretty small... i also think that “decomposition” is an inapt term, since the hydrogen is essentially in a free proton state, with electrons freely flowing around the medium. You can’t really “decompose” hydrogen much further. Edit: I guess with volume, the bond energy is significant... https://dash.harvard.edu/bitstream/handle/1/9569212/Silvera_Metallic.pdf

Hmm... that definitely sounds like a glitch... I don’t think I can help with that... the only thing that happened to me that was similar was when I was doing a rendezvous with my duna orbiter, and lost all control when I switched to my “mothership”... I saved and reloaded, and it worked for me...

That makes no sense... c4 doesn’t decompress, it reacts... a material transitioning into another state of matter is not “decomposition,” a semiliquid form of compressed hydrogen transitioning to hydrogen gas is not “decomposition.” What are we reacting? Like I said, expansion of a liquid, into a gaseous state, is going to cool... if you’re trying to say “react” than say “react,” decompression is very different from a chemistry standpoint

Decompression always results in cooling... like why frost forms on the valve of a high pressure nozzle venting into the atmosphere... or even an expanding universe is a “cooling” universe... unless there’s something I’m missing about metallic hydrogen, it should abide by the same laws of physics that dictate heat dissipation in “regular” compressed (or liquified) gases... energy/heat must go in, to compress it, heat must be released upon expansion... it’s a matter of entropy and energy conservation... again, unless I am missing something about metallic hydrogen?

First, make sure your navball is set to “target.” As you’re getting close, make sure you’re set to retrograde, and burn until the velocity is zero. Set craft toward “target” and burn; if you’re within 500 m, you don’t want to burn too hard, maybe to about 15-20 m/s, then switch back to retrograde. As you approach, watch your distance, and wait to burn retrograde... depending on a few variables, this may set you really close, and you’ll just burn retrograde (to 0 m/s), and park your craft right next to the target... if you’re not close, you need to repeat target burn then retrograde burn, until you close in... takes some practice, there are a few decent tutorials on the ksp wiki... also, if you’re docking, make sure you’re targeting the target ship docking port, and vice versa Edit: it seems like you’re already familiar with orbital rendezvous, so I skipped that part, but you should have the ship you want to dock to set as your target

The vacuum isp on the poodle (350) is better than the reliant (310)

Is there a way to set the parachute(s) to deploy at a surface relative altitude instead of sea level altitude? For example, if I happen to descend over a mountain, the default parachute deploy height will be well below ground level... while I know I can manually change the deploy altitude in the part menu, which I sometimes need to do upon descent, is there a way to get the ‘chutes to deploy at the relative altitude instead of absolute altitude? I’m on a ps4, so I can’t use any mods...