Abstract. 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. Metastable metallic hydrogen would be a very light-weight, low volume, powerful rocket propellant. One of the characteristics if a propellant is its specific impulse, Isp . Liquid (molecular) hydrogen-oxygen used in modern rockets has an Isp of ~460s; metallic hydrogen has a theoretical Isp of 1700 s! Detailed analysis shows that such a fuel would allow single-stage rockets to enter into orbit or carry economical payloads to the moon. If pure metallic hydrogen is used as a propellant, the reaction chamber temperature is calculated to be greater than 6000 K, too high for currently known rocket engine materials. By diluting metallic hydrogen with liquid hydrogen or water, the reaction temperature can be reduced, yet there is still a significant performance improvement for the diluted mixture.
Great write up. That is exciting stuff.
Quote from: Paul Howard on 01/10/2012 06:16 amGreat write up. That is exciting stuff.Sorry, but I fail to be excited. To me, this is yet more starry-eyed dreaming about possibilties that will most likely never come to pass due to lack of budget and interest. Instead, IMO, we would be better off focusing all our efforts on the current and immediate problem of access to our National Laboratory in Space in case Russia has to stand down, as well as the imminent problem of preventing a runaway Kessler Syndrome which has the potential to end all spaceflight for good.After all, did the last NIAC really accomplish much?
I like the metallic hydrogen concepts. I wonder what the practical Isp would be? Can you use evapourative water cooling for the rocket chamber.
I once had a Professor who advised me, "If you want to win a NIAC proposal, make sure to break at least two fundamental laws of physics. They won't take you seriously if you break only one..."
I like the metallic hydrogen concepts. I wonder what the practical Isp would be? Can you use evapourative water cooling for the rocket chamber. http://iopscience.iop.org/1742-6596/215/1/012194/pdf/1742-6596_215_1_012194.pdfQuoteAbstract. 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. Metastable metallic hydrogen would be a very light-weight, low volume, powerful rocket propellant. One of the characteristics if a propellant is its specific impulse, Isp . Liquid (molecular) hydrogen-oxygen used in modern rockets has an Isp of ~460s; metallic hydrogen has a theoretical Isp of 1700 s! Detailed analysis shows that such a fuel would allow single-stage rockets to enter into orbit or carry economical payloads to the moon. If pure metallic hydrogen is used as a propellant, the reaction chamber temperature is calculated to be greater than 6000 K, too high for currently known rocket engine materials. By diluting metallic hydrogen with liquid hydrogen or water, the reaction temperature can be reduced, yet there is still a significant performance improvement for the diluted mixture.
Quote from: simonbp on 01/10/2012 03:09 pmI once had a Professor who advised me, "If you want to win a NIAC proposal, make sure to break at least two fundamental laws of physics. They won't take you seriously if you break only one..."Awesome! I'll start writing up my plans for two of these then NO, I don't want to hear medium launchers could do the same job!!
I believe they are built in orbit (possibly out of raw materials), so....
DRADIS CONTACTS...SPIN UP THE FTL DRIVES CHRIS!
Quote from: Robotbeat on 01/10/2012 06:09 pmI believe they are built in orbit (possibly out of raw materials), so.... You've got a bloody answer for everything, you ...
Anyone we know submitting a proposal?
The problem is, production of (any) radioisotopes is a really tricky business. Even if NASA had unlimited money and materials, it would still legally have to go through the DoE to produce Pu-238 (a legacy of AEC having a monopoly on atomic research). Slightly better would be an independent company to produce it, but it would still legally have to be purchased by DoE and then furnished to NASA.That's why I'm pulling for the metal combustion project; it has no silly legacy legal restrictions to deal with.
That's why I'm pulling for the metal combustion project; it has no silly legacy legal restrictions to deal with.
Quote from: QuantumG on 01/10/2012 01:18 amAnyone we know submitting a proposal? I'm submitting a kinetic impact powered rocket CATS proposal. My latest refinements use ISRU to provide most of the mass of the impactors.
Metal combustion? That isn't referenced in the article here
(and the metallic hydrogen concept sounds like it isn't practical at all).
Wowzers, NASA.gov retweeted the article to their 1,739,545 followers @NASA NASA Check out this story about the call for revolutionary ideas from NASA's Innovative Advanced Concepts Program tinyurl.com/7njqg9wThat's a first for us!
There are some MSFC AIAA papers from a few years back about metallic hydrogen propulsion that are quite interesting. Effectively, once it is in the metallic state, it should (in theory) be pretty stable (over a range of temperatures). So, you load a whole bunch of it into a pressure tank in your rocket and slowly let it trickle out. As the pressure is released, it phase changes to gas, releasing a massive amount of thermal energy in the process. You then use this thermal energy to heat a reaction mass fluid (i.e. water), and shoot it out at very high velocities. The real trick is that by changing the mix ratio between hydrogen and water, you can trade thrust and efficiency, making a metallic hydrogen/water SSTO rocket possible. Such a vehicle itself would be mechanically very simple, with all the real complexity (and needed development) in the production of metallic hydrogen on the ground.
You can always use an ablative chamber, which wouldn't really have a limit in chamber temperature (though at some point, you ablate so fast you're basically operating a sort of solid rocket!).That said, yeah. I'm more optimistic of fusion power than metallic hydrogen being used in this manner at any time soon.
Quote from: IsaacKuo on 01/10/2012 07:16 pmQuote from: QuantumG on 01/10/2012 01:18 amAnyone we know submitting a proposal? I'm submitting a kinetic impact powered rocket CATS proposal. My latest refinements use ISRU to provide most of the mass of the impactors.Cool! If you want threads, help, exposure, etc. We'll provide!
Quote from: Chris Bergin on 01/10/2012 08:39 pmQuote from: IsaacKuo on 01/10/2012 07:16 pmQuote from: QuantumG on 01/10/2012 01:18 amAnyone we know submitting a proposal? I'm submitting a kinetic impact powered rocket CATS proposal. My latest refinements use ISRU to provide most of the mass of the impactors.Cool! If you want threads, help, exposure, etc. We'll provide! Thanks! I have posted ideas about kinetic impact powered rockets here in the past, and will continue to do so occasionally.What about others? There are a lot of people who more regularly post ideas in this Advanced Concepts forum. I would have guessed at least two or three others would also be submitting proposals to this NIAC call.
There's no way metallic hydrogen can be "metastable" at the temperatures and pressures humans use for their rockets IMO. They way the investigate it now, is with massive diamond anvils and they hope to get a measurement for a millisecond or something like that.
Arguably, the Great Red Spot on Jupiter runs on metallic hydrogen. It wouldn't work if metallic hydrogen was metastable.
Quote from: Warren Platts on 01/10/2012 10:57 pmThere's no way metallic hydrogen can be "metastable" at the temperatures and pressures humans use for their rockets IMO. They way the investigate it now, is with massive diamond anvils and they hope to get a measurement for a millisecond or something like that.No they don't investigate it with diamond anvils, because no one has succeeded in making it yet. They are trying to make it in diamond anvils. Since no one has seen it yet we really don't know wether it is metastable. Theory says it might be, but theory on dense hydrogen is difficult, so we can't know for sure. Try to read the article about it. It is all discussed.Quote from: Warren Platts on 01/10/2012 10:57 pm Arguably, the Great Red Spot on Jupiter runs on metallic hydrogen. It wouldn't work if metallic hydrogen was metastable.Any evidence for this?
Homogeneous models (no helium-hydrogen phase separation) that invoke gravitational contraction as the sole power source accurately predict Jupiter’s temperature, but imply that Saturn should have achieved its present temperature over two billion years ago (Grossman et al. 1980). Inhomogeneous models that invoke helium phase separation and sedimentation within the metallic envelope predict slower cooling, reconciling Saturn’s predicted temperature with the observed temperature (Fortney and Hubbard 2003). However, Jupiter's helium mass fraction Y determined by the Galileo probe is 0.231—significantly less that the protosolar value of 0.27 (Guillot et al. 2004). The natural explanation for this discrepancy is helium phase separation, but under the EOS's consistent with Saturn's temperature and age, Jupiter should be hotter than it is now (Fortney and Hubbard 2003). Guillot et al. (2004) propose that core erosion and redistribution could provide the needed cooling mechanism. An alternate explanation is that the GRS functions as an expansion valve and gravity as a compressor in a natural refrigeration system that cools the planet.
I think you should focus on stuff that NASA would be most interested in, like a totally novel lunar ISRU concept, a novel concept for a lander/rover to explore a permanently shadowed crater, etc.Your idea on a gold mining technique would be far better for pitching to private investors than to NASA. Just my friendly opinion. Best of luck everyone with their proposals!
NASA's Innovative Advanced Concepts (NIAC) Symposium will be held March 27-29 at the Westin Pasadena Hotel, 191 North Los Robles Ave., in Pasadena, Calif. The NIAC examines early stage concepts that may lead to advanced and innovative space technologies critical for NASA to enable missions 10 to 100 years from today.To attend this free registration conference, you must sign up online at: http://events.Signup4.com/NIAC2012
I would like to see the power point for "Nuclear Propulsion Through Direct Conversion of Fusion Energy" from the talk.
...Someone with the math skills and engineering tradoff knowledge would have to say if this could work or not.Just a thought.
The difficulty with NIAC is that they always want "game-changing" technologies that will make spaceflight free and can be developed for 25K.
The difficulty with NIAC is that they always want "game-changing" technologies that will make spaceflight free and can be developed for 25K. I try to point out that we need patient work to analyze the tasks that made the Shuttle cost ten times what was predicted to maintain. No interest so far.
[One] might find it surprising that EVERY study on cost overruns blames a lack of focus on investment in basic tech development as a major contributor to these overruns.
In fact, given your interest in finding out why space missions cost more than predicted, but your seeming dislike of the idea behind NIAC, you might find it surprising that EVERY study on cost overruns blames a lack of focus on investment in basic tech development as a major contributor to these overruns.
Quote from: LegendCJS on 06/20/2012 03:15 pmIn fact, given your interest in finding out why space missions cost more than predicted, but your seeming dislike of the idea behind NIAC, you might find it surprising that EVERY study on cost overruns blames a lack of focus on investment in basic tech development as a major contributor to these overruns.I thought a bigger problem nowadays was the "TRL-5 hole," ie. the fact that NASA, DoD, etc. will fund your basic research and development up to TRL 3 or so, but don't really have programs for bringing an idea from paper studies and lab demos of key parts up to at least basic system validation. So you have lots of promising technologies that have seen some development, but they haven't seen anything approaching the level of development needed to start planning a mission/vehicle around them, at least not without accepting a great deal of design risk.