Quote from: Star One on 11/06/2016 06:12 pmBy the way why is it appearing on a site like this first rather than a more mainstream science site?It kind of was here back in August: https://www.sciencenews.org/article/pressure-make-metallic-hydrogen
By the way why is it appearing on a site like this first rather than a more mainstream science site?
What is the reason for the high isp of metallic hydrogen?
How much of a case has been made that metallic hydrogen will be metastable and up to what pressure? I couldn't find any information on that but thought I had gathered from somewhere that metastability does not imply anything like ambient pressure or that it can be used to build structures, as I saw thrown around in a few article headings.What is claimed here is just that we have created some metallic hydrogen, right? What sort of confidence is there in it's properties?
Metallic hydrogen: The most powerful rocket fuel yet to exist.
Quote from: Sam Ho on 11/06/2016 09:30 pmMetallic hydrogen: The most powerful rocket fuel yet to exist.Bit of a hyperbole there, no ? Project Orion ? Also, NERVA certainly existed and could probably exceed this purely theoretical ISP of a purely theoretically metastable material.
Quote from: Stormbringer on 11/06/2016 05:18 pmalso its not as simple as solid, liquid and condensed gas... the articles seem to say that the solid form has at least three probably different organizational forms.That's the most critical part for consideration of a solid plasma.In Frank Chen's unpublished continuation to his Plasma Physics book, (which I have a draft copy of), he discusses theoretical solid plasmas - the organization of the "material" will matter.(Around this time had a discussion/notes of a fusion "combustion chamber" based on a solid plasma, however was told that no one would ever build a large enough vehicle for its use, since the Saturn V was considered "uneconomic" due to size. )
also its not as simple as solid, liquid and condensed gas... the articles seem to say that the solid form has at least three probably different organizational forms.
The rocketry application was published in a 2009 conference paper, so it isn't all that new, but back then there were no samples of metallic hydrogen.Silvera, Isaac F. and John W. Cole. 2010. Metallic hydrogen: The most powerful rocket fuel yet to exist. In International Conference on High Pressure Science and Technology, Joint AIRAPT-22 & HPCJ-50 : [proceedings] : 26-31 July 2009, Tokyo, Japan. Journal of Physics Conference Series 215(1): 012194.http://nrs.harvard.edu/urn-3:HUL.InstRepos:9569212
Bit of a hyperbole there, no ? Project Orion ?
Also, NERVA certainly existed and could probably exceed this purely theoretical ISP of a purely theoretically metastable material.
Quote from: allhumanbeings07 on 11/06/2016 06:59 pmQuote from: Elmar Moelzer on 11/06/2016 06:39 pmMy question is: how much does it cost to make enough metallic hydrogen for a SSTO launch with 25 tonnes of payload? If it costs too much, then there is little point to it unless there is a path towards bringing costs down.Until last month the price per kg was infinity, now after producing however much they did it's probably down into the mere quadrillions- so one month from now it should be completely free. If it is a room temperature super conductor, they'll certainly be interested in producing as much of it as they can... who knows how easy or difficult it will be to produce it in 30, or 50, or 100 years, fingers crossed...Hadn't heard about metallic hydrogen as a potential chemical fuel before, but apparently it's been theorized for some time. Are there any other interesting theoretical fuels out there which might be synthesized and haven't been yet?yeah. go to project rho and look at their engine table. several of the fuels listed there are pretty much what you are asking about. E.G; metastable helium.http://www.projectrho.com/public_html/rocket/enginelist.php#metaheliumhestarif you could make atoms out of unusual particles like magnetic monopoles the energy released by breaking their *chemical* bonds could release more energy that antimatter or certainly atomic reactions. this is because the energy is inversely proportional to the length of the bonds whether electronic bonds or nuclear bonds. the bonds of magnetic monopole matter would be 2000 time shorter than those in regular matter and antimatter. and breaking a magnetic monopole atoms nucleus apart or fusing them would make more energy still than breaking electronic bonds. so if you could find either monopoles or some other suitable nucleon and electron substitute you could vastly out-perform even antimatter engines.we don't have monopoles but we have created synthetic atoms out of stuff that doesn't normally form atoms such as kaons and muons. they are very unstable and last a tiny amount of time before breaking up. but there is reason to hope that some combination or some amount of a material like this may be more persistent. Neutrons die in 11 or so minutes when alone but are stable possibly forever in an atomic nucleus. Likewise kaonium (or was it muonium?) lasts longer than individual particles of their species.
Quote from: Elmar Moelzer on 11/06/2016 06:39 pmMy question is: how much does it cost to make enough metallic hydrogen for a SSTO launch with 25 tonnes of payload? If it costs too much, then there is little point to it unless there is a path towards bringing costs down.Until last month the price per kg was infinity, now after producing however much they did it's probably down into the mere quadrillions- so one month from now it should be completely free. If it is a room temperature super conductor, they'll certainly be interested in producing as much of it as they can... who knows how easy or difficult it will be to produce it in 30, or 50, or 100 years, fingers crossed...Hadn't heard about metallic hydrogen as a potential chemical fuel before, but apparently it's been theorized for some time. Are there any other interesting theoretical fuels out there which might be synthesized and haven't been yet?
My question is: how much does it cost to make enough metallic hydrogen for a SSTO launch with 25 tonnes of payload? If it costs too much, then there is little point to it unless there is a path towards bringing costs down.
The smallest magatoms have diameters of 3E-19 m, 300 million times smaller than an atom of conventional matter. As a typical magatom is 10,000 times heavier than a typical conventional atom, magmatter�s typical density is 1E33 kg/m3. Since force is energy per unit distance, the force needed to break a magchemical bond is larger than that needed to break an electronic chemical bond by a factor of the energy scaling (300 GeV / 13.7 eV) divided by the length scaling, or 7 million trillion (7E18). The strength of a material is usually defined as the force per unit area required to make the material fail. Since each magchemical bond can withstand 7E18 times greater force, and there are (300 million)2 times more bonds per unit area, the strength of magmatter is about 8E35 times greater than that of its normal matter equivalent.
EDIT: The short version of the above is that because there would presumably be much more mass and energy packed into a smaller space synthetic matter could provide more energy than antimatter even though all are constrained by the mass energy equivalence in the famous equation.
No, you cannot exceed e=mc^2. Any energy that you store in "chemical bonds" will simply show up as extra mass of the fuel. The energy per unit mass cannot surpass matter/antimatter.
Now, could we get some metallic oxygen, too? Breaking an O=O bond takes 498 kJ/mol, and we need half a mole per mole of hydrogen, so that's a total energy release of about 971 kJ/mol. Or, going into totally wild speculation, is a hydrogen-oxygen alloy possible?
Quote from: Proponent on 11/08/2016 02:38 pmNow, could we get some metallic oxygen, too? Breaking an O=O bond takes 498 kJ/mol, and we need half a mole per mole of hydrogen, so that's a total energy release of about 971 kJ/mol. Or, going into totally wild speculation, is a hydrogen-oxygen alloy possible?By definition, no. Alloys exist as combinations of metals because of the properties of metals - which Oxygen most definitely is not . Hydrogen is an unusual case; it's on the far left side of the periodic table because it's expected to be a metal, were it not for the quantum mechanics involved in the element's simplicity.
Quote from: RotoSequence on 11/08/2016 03:09 pmQuote from: Proponent on 11/08/2016 02:38 pmNow, could we get some metallic oxygen, too? Breaking an O=O bond takes 498 kJ/mol, and we need half a mole per mole of hydrogen, so that's a total energy release of about 971 kJ/mol. Or, going into totally wild speculation, is a hydrogen-oxygen alloy possible?By definition, no. Alloys exist as combinations of metals because of the properties of metals - which Oxygen most definitely is not . Hydrogen is an unusual case; it's on the far left side of the periodic table because it's expected to be a metal, were it not for the quantum mechanics involved in the element's simplicity.Oxygen will convert to a metallic allotrope at about 132 GPa. Many non-metal atoms have a metallic allotrope at sufficient pressures.https://en.wikipedia.org/wiki/Solid_oxygen#Metallic_oxygenhttps://en.wikipedia.org/wiki/Nonmetal#AllotropesIt just means that when pressures are sufficient to pack the atoms so tightly together that the valence electrons begin to migrate freely through the substance then it will demonstrate metallic properties.As far as I know, most of these metallic allotropes are not meta-stable and probably not all that useful for spaceflight unless you have a way to sustain those pressures without using massive containing structures.