Co-discover of Metallic Hydrogen wrote paper on metallic hydrogen for rockets

[Tom Kalbfus]

What is the maximum jump that can be achieved if we introduced metallic hydrogen into a Traveller campaign?

November 05, 2016
Co-discover of Metallic Hydrogen wrote paper on metallic hydrogen for rockets

On October 5th 2016, Ranga Dias and Isaac F. Silvera of Lyman Laboratory of Physics, Harvard University released the first experimental evidence that solid metallic hydrogen has been synthesized in the laboratory.

It took 495 GPa pressure to create. The sample is being held in the cryostat in liquid nitrogen.

Atomic metallic hydrogen, if metastable at ambient pressure and temperature could be used as the most powerful chemical rocket fuel, as the atoms recombine to form molecular hydrogen. This light-weight high-energy density material would revolutionize rocketry, allowing single-stage rockets to enter orbit and chemically fueled rockets to explore our solar system. To transform solid molecular hydrogen to metallic hydrogen requires extreme high pressures.

Isaac Silvera headed a 2011-2012 NIAC metallic hydrogen project and also co-wrote a 2010 paper on metallic hydrogen rockets.

NOTE Nextbigfuture believes until metallic hydrogen becomes very, very cheap, it will be far more valuable for possible superconducting properties than for rocket fuel. Even very high performance rocket fuel. If metallic hydrogen is a room temperature superconductor that is metastable after releasing the pressure that created it, and the critical current is very high, then improvements to engines and high performance magnetic sails would be possible. This will be considered in future posts.

Metallic Hydrogen: The Most Powerful Rocket Fuel Yet to Exist Isaac F. Silvera and John W. Cole

There was a 22 page presentation in 2012 on metallic hydrogen as a rocket fuel

Some Remarkable Properties of Metallic Hydrogen
•Recombination of hydrogen atoms releases 216 MJ/kg
•Hydrogen/Oxygen combustion in the Shuttle: 10 MJ/kg
•TNT 4.2 MJ/kg
•Theoretical Specific Impulse, Isp
•Metallic Hydrogen 1000-1700s
•Molecular hydrogen/oxygen ~460 s (space shuttle)
•Metallic density
about 12-1315 fold of liquid molecular hydrogen [lab results of actual metallic hydrogen was 15 times denser]
•Sufficient thrust for single-stage to orbit; explore outer planets

Silvera Goals

•Produce metallic hydrogen in small quantities [now this is done in 2016]
•Test for metastability [next on the objectives]
•Determine Critical Temperature for conversion
•Develop a method to scale down the critical pressure [Silvera has ideas about injecting electrons]

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. Tthe 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 of 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.

http://www.nextbigfuture.com/2016/11/co-discover-of-metallic-hydrogen-wrote.html

 

[heron61]

Metallic hydrogen would radically change Traveller starships, since being able to carry jump fuel that was 15 x denser than liquid hydrogen would mean that a jump-6 ship would only need to devote 4% of its volume to jump fuel. Assume that the difficulties of storing metallic hydrogen increase the complexity and size of the tanks, and you could have a ship capable of making Jump-6 twice before refueling and still only have fuel tanks take up 10-12% of the ship's volume.

On the downside, I don't think that wilderness refueling would work with metallic hydrogen, since I'm betting that even at TL15 the equipment needed to create vast amounts of metallic hydrogen isn't small. Instead, ships would refuel at starports, but would carry sufficient fuel for multiple jumps. A possible alternative might be a metallic hydrogen fuel processor that was 10x the size of standard fuel processors.

In any case, I'd bet that there would be a whole lot of Jump-4 to Jump-6 ships around, including small traders, and I'd expect the Type S Scout to be at minimum jump-3, with Jump-4 & Jump-5 models not being uncommon.

 

[FallingPhoenix]

Yeah, it seems like the biggest limiting factor at that point would be spare parts for your jump drive. Which might mean that the main routes would either all have higher TL worlds, or that the starports would carry higher TL parts on the main routes.

 

[DanDare2050]

Given that Traveller is hundreds of years in the future the answer is probably that metallic hydrogen is what jump drives have been based on all the time. Fuel scoops process liquid to metallic and the refining process still removes impurities.

 

[Tom Kalbfus]

I'd rule that metallic hydrogen is expensive, and would probably be used by the military for things like crossing rifts, and doing long range exploration missions. A jump-6 starship using metallic hydrogen for fuel could travel up to 90 parsecs before needing to refuel, or else, you might have a Jump-6 scout ship, have the larger jump drive plus maneuver drive that becomes possible due to the space saved by using metallic hydrogen. the down side is that metallic hydrogen is highly explosive, if the ship gets into combat and the fuel tank gets hit, that would likely detonate all of the metallic hydrogen with enough explosive force to completely obliterate the ship. You see metallic hydrogen is its own oxidizer the chemical reaction is H + H -> H2 + energy, and that is a lot of energy, the theoretical specific impulse for a chemical rocket is 1700 seconds at 1-g, it can accelerate at 1-g with a chemical rocket for 28 minutes, reaching a final velocity change of 17 km/sec, and that is a 1-stage rocket!

 

[AndrewW]

the down side is that metallic hydrogen is highly explosive, if the ship gets into combat and the fuel tank gets hit, that would likely detonate all of the metallic hydrogen with enough explosive force to completely obliterate the ship.

That could be useful. The Corbomite Maneuver comes to mind (see also The Deadly Years).

 

[wbnc]

I'd rule that metallic hydrogen is expensive, and would probably be used by the military for things like crossing rifts, and doing long range exploration missions. A jump-6 starship using metallic hydrogen for fuel could travel up to 90 parsecs before needing to refuel, or else, you might have a Jump-6 scout ship, have the larger jump drive plus maneuver drive that becomes possible due to the space saved by using metallic hydrogen. the down side is that metallic hydrogen is highly explosive, if the ship gets into combat and the fuel tank gets hit, that would likely detonate all of the metallic hydrogen with enough explosive force to completely obliterate the ship. You see metallic hydrogen is its own oxidizer the chemical reaction is H + H -> H2 + energy, and that is a lot of energy, the theoretical specific impulse for a chemical rocket is 1700 seconds at 1-g, it can accelerate at 1-g with a chemical rocket for 28 minutes, reaching a final velocity change of 17 km/sec, and that is a 1-stage rocket!

Acetelyne also has an issue with stability. if you drop an acetylene bottle it can spontaneously decompose and detonate.

In very specific roles where the risk of having something trigger Metalic Hydrons instability the inherent instability becomes an advantage. with a good deal of gravity control and other Tl-12 to 15 tricks up their sleeve, a ship with prototype, or limited run Metalic Hydrogen feul and reaction thrusters might be extremely useful. it might not be a widespread tech. but when it is useful it would be very useful.

one use I could see it being well suited to would be as propellant for a missile. extremely small volume, extremely high specific impulse...

 

[Tom Kalbfus]

At higher tech levels, you can have metallic anti-hydrogen, it has the same density a water, about 1 ton per cubic meter, and because it is solid, compact, and mas magnetic properties (it is a superconductor after all) it is easy to contain, and then you have lost of jump fuel, a d-ton of normal hydrogen has the same space as 14 tons of metallic hydrogen, you can with advanced technology have jump-90 jump drives, with the same space as a Jump-6 drive at tech level 15, that means you can travel to the galactic core in only 100 jumps from Terra, this would take approximately 1.36 years to do. You need some sort of mechanism to compact all that hydrogen you scoop from gas giants into metallic form, but then that is advanced technology. This is the same level of technology that is Featured in the Foundation setting, you could barely have a Galactic Empire.

 

[Rikki Tikki Traveller]

MMH (Meta-Stable Metallic Hydrogen) has been around in Traveller for a while.

I THINK HG1 even had some rules on it, but not sure.

From what I remember - Very Expensive, but 1/10th the volume. If you take a fuel hit, you loose ALL your fuel, not just a fraction like liquid hydrogen. No wilderness refueling, no on-board Purifiers to create it.

Another option, mentioned above is to assume that MMH is what has been used all along. The Fuel Purifiers actually purify the gaseous hydrogen (or water or whatever) and convert it to MMH for storage in the fuel tanks.

 

[Condottiere]

1. How do you create metallic hydrogen? Considering the retail pricetag, I'd prefer to manufacture it myself.

2. Costing at least four hundred times more than retailed refined hydrogen, or eight hundred if you account for efficiency, I'd just reserve some tankage for an emergency.

 

[Reynard]

Rikki, from HG2e, "it is possible to store hydrogen at room temperature using a non–flammable metal hydride matrix. This takes up more space but is safer.".

 

[Tom Kalbfus]

1. How do you create metallic hydrogen? Considering the retail pricetag, I'd prefer to manufacture it myself.

2. Costing at least four hundred times more than retailed refined hydrogen, or eight hundred if you account for efficiency, I'd just reserve some tankage for an emergency.

If you want to travel to the Galactic Core, you would probably want a high tech starship with the capability of manufacturing its own metallic hydrogen while skimming gas giants, then you could have a Jump-90 jump drive, it is about 10,000 parsecs to the Galactic Core so you would need to make 111.1 jumps, a more advanced jump drive might be able to transverse Jump space in 1 day instead of 5, so that would make it about 3 to 4 months to reach the Galactic Core, this is the sort of tech you'd need if you wanted a Galactic Empire.

 

[Condottiere]

Outside of the cost, you need twice the space.

Also, I think you'd have to reprocess it back to liquidity to make it usable by the jump drive.

 

[Tom Kalbfus]

Outside of the cost, you need twice the space.

Also, I think you'd have to reprocess it back to liquidity to make it usable by the jump drive.

That is simple, you raise the temperature until it melts, and then you have the reaction H + H -> H2 + energy. Hydrogen reacts with itself in monoatomic form, Metallic hydrogen's crystal lattus holds it in monoatomic form, once you release it from its crystalline form the hydrogen atoms react with each other to form molecular hydrogen, and this releases a lot of energy, the temperature of the reaction is in excess of 6000 degrees Kelvin, which is about the temperature of the surface of our Sun. Getting metallic hydrogen back into gaseous form is not really a big problem!
What's wrong, don't you like the idea of a Galactic Empire? This would be the enabling technology for that, and its entirely consistent with Traveller rules. There must be some move advanced civilizations out there than 3I for instance. Maybe in the Andromeda Galaxy for example.

 

[wbnc]

Also, I think you'd have to reprocess it back to liquidity to make it usable by the jump drive.

That is simple, you raise the temperature until it melts, and then you have the reaction H + H -> H2 + energy. Hydrogen reacts with itself in monoatomic form, Metallic hydrogen's crystal lattus holds it in monoatomic form, once you release it from its crystalline form the hydrogen atoms react with each other to form molecular hydrogen, and this releases a lot of energy, the temperature of the reaction is in excess of 6000 degrees Kelvin, which is about the temperature of the surface of our Sun. Getting metallic hydrogen back into gaseous form is not really a big problem!
What's wrong, don't you like the idea of a Galactic Empire? This would be the enabling technology for that, and its entirely consistent with Traveller rules. There must be some move advanced civilizations out there than 3I for instance. Maybe in the Andromeda Galaxy for example.[/quote]

I'm not familiar wihthe reaction Your describing...But if the process s that intense you wouldn't need a fusion reaction to generate power. Just destabilize a bit of Metallic hydrogen and stand back.

 

[Condottiere]

The Third Imperium is a large enough sandbox to interact with, and even that has huge gaping holes.

 

[Tom Kalbfus]

The Third Imperium is a large enough sandbox to interact with, and even that has huge gaping holes.

Well if you have a faster FTL drive, you don't bother so much with the non habitable planets. For instance, have you ever seen a Star Wars movie where anyone actually put on a space suit? Nope, all planets shown were habitable, even the desert planets, even the planet Hoth! Seems the characters in Star Wars are either in space ships, space stations or on a habitable planet, the one exception was when the Millenium Falcon landed unknowingly in the gut of a giant space slug, which they mistook to be an asteroid cave, and even then, they only needed filter masks! They had to pass by a lot of uninhabitable planets to get to those habitable ones, but I guess that if you can travel across the Galaxy in a matter of hours, you can ignore a lot of planets.

 

[Condottiere]

In theory, the Empire should never find any secret rebel base, regardless how many reconnaissance probes they send out.

While I find subsector sandboxing somewhat claustrophobic, it does allow a campaign to flesh out most systems in it, strictly speaking, about as far as the average characters can afford to wander around within a reasonable time frame.

 

[Tom Kalbfus]

In theory, the Empire should never find any secret rebel base, regardless how many reconnaissance probes they send out.

While I find subsector sandboxing somewhat claustrophobic, it does allow a campaign to flesh out most systems in it, strictly speaking, about as far as the average characters can afford to wander around within a reasonable time frame.

How do you flesh out a Galactic Empire? What if you used system cards, get a deck of star system cards and shuffle them, and when the PCs explore a new star system, you pull out a new card and that is what the PCs find, You can have a whole bunch of prepared systems that way, so which ever direction and however far the PCs travel, you just pull out a new card every time they enter a new star system.