It was also hardly easy to manufacture considering the amount of preparation they had to make with the synthetic diamond vice alone. That pressure is ridiculous as well and how much energy did that use to create. Going to be as much about how you manufacture it as to if it's metastable.
Quote from: Proponent on 11/09/2016 05:23 pmQuote from: DMeader on 11/09/2016 04:00 pmQuote from: Proponent on 11/08/2016 02:38 pmWith metallic hydrogen, the atoms need be broken out of the metallic matrix, but that probably takes a lot less energy. Once that happens, aren't the individual atoms going to want to immediately revert to the H-H configuration (covalent bond) with commensurate release of energy?No doubt, and, rereading the article and clicking through the links, the idea seems to be to rely on that energy alone, not bothering with the oxygen.An Isp of 1700 s corresponds to an effective exhaust velocity of about 17 km/s. For getting to LEO that's actually too high, if the objective is to minimize the amount of metallic hydrogen. It might be optimal to add a cheap working fluid, ideally a monatomic one. That would have the added advantage of keeping the temperature down.The paper said that a monopropellant would have an Isp of 1700s and a temperature of around 7000K. Hydrogen diluent to take the temperature down to 3500K-3800K would result in an Isp of 1030-1120s, and water diluent would have an Isp of 460-540s.http://nrs.harvard.edu/urn-3:HUL.InstRepos:9569212
Quote from: DMeader on 11/09/2016 04:00 pmQuote from: Proponent on 11/08/2016 02:38 pmWith metallic hydrogen, the atoms need be broken out of the metallic matrix, but that probably takes a lot less energy. Once that happens, aren't the individual atoms going to want to immediately revert to the H-H configuration (covalent bond) with commensurate release of energy?No doubt, and, rereading the article and clicking through the links, the idea seems to be to rely on that energy alone, not bothering with the oxygen.An Isp of 1700 s corresponds to an effective exhaust velocity of about 17 km/s. For getting to LEO that's actually too high, if the objective is to minimize the amount of metallic hydrogen. It might be optimal to add a cheap working fluid, ideally a monatomic one. That would have the added advantage of keeping the temperature down.
Quote from: Proponent on 11/08/2016 02:38 pmWith metallic hydrogen, the atoms need be broken out of the metallic matrix, but that probably takes a lot less energy. Once that happens, aren't the individual atoms going to want to immediately revert to the H-H configuration (covalent bond) with commensurate release of energy?
With metallic hydrogen, the atoms need be broken out of the metallic matrix, but that probably takes a lot less energy.
...and it's gonehttp://www.independent.co.uk/news/science/metallic-hydrogen-disappears-technology-revolutions-superconductor-faster-computers-super-efficient-a7593481.html
This is good news, now they are forced to reproduce it earlier than expected.
Quote from: IRobot on 02/24/2017 09:54 amThis is good news, now they are forced to reproduce it earlier than expected.On the other hand, the fact that it immediately disappeared after the failure of the diamond, and the fact that the diamond was destroyed so completely, and in a fashion that had never been seen before (indicating massive force) makes me suspect that metallic hydrogen (assuming that sample really was metallic hydrogen) is probably not metastable. Which would mean no new wonder rocket fuel (or super-explosive, or superconductor or all the other fantastic stuff some people were already expecting...). Which is kind of a bummer...
As the article I linked to points out this is an assumption that cannot be made at this time.
Quote from: IRobot on 02/24/2017 09:54 amThis is good news, now they are forced to reproduce it earlier than expected.On the other hand, the fact that it immediately disappeared after the failure of the diamond, and the fact that the diamond was destroyed so completely, and in a fashion that had never been seen before (indicating massive force) makes me suspect that metallic hydrogen (assuming that sample really was metallic hydrogen) is probably not metastable.
Am I reading this right? They only did this once? What the hell were they doing announcing it if they've only done it once? What happened to reproducibility?
Even if the stuff is real and metastable it is mostly only of theoretical value. It would probably cost billions to produce a gram of the stuff. Rocket fuel? Not likely.