Solid or Metastable Metallic Hydrogen as fuel

[Brian Blank]

I was reading an article on Jupiter and they were talking about Solid Hydrogen Ice and Metallic Hydrogen. I got to thinking, with the gravitics and materials technology of the Imperium why not use Solid Hydrogen or Metallic Hydrogen for Starships instead of LHyd. Fuel Tankage would be smaller and more room would be available for drives, cargo, weapons etc.

Here are a couple of links to what I'm talking about.

http://www.halfbakery.com/idea/Metallic_20Hydrogen

http://en.wikipedia.org/wiki/Metallic_hydrogen

 

[spank]

Solid/slush hydrogen

I posted an idea about this a while ago, here is a link to the thread.

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=3402

 

[atpollard]

Do not overlook the consequences that 1 hit to "fuel" and the ship vaporizes in a really big boom.

 

[Brian Blank]

Do not overlook the consequences that 1 hit to "fuel" and the ship vaporizes in a really big boom.

I posted an idea about this a while ago, here is a link to the thread.

http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=3402

Thanks for the link, Spank. Nice to see I'm on the same wavelength with someone. I'd completly forgotten about Slush Tankage.

AT, not sure you wouldn't get the same thing with LHyd on a standard ship. One good hit to the tanks and ....BOOM !!

I'm thinking maybe Pellets or Slugs of fuel as well. We are already postulating that you can have fuel purifiers that can seperate and liquify hydrogen on 100ton ships at TL12-13. Who knows what is possible at higher Tech Levels

 

[Zembar]

Doesn't said "boom" require oxygen?

If the hydrogen is used for fusion, there shouldn't be any need for oxygen. Also, why would anyone store oxygen and hydrogen in the same place? Sound like a very very bad idea.

-- Zembar

 

[atpollard]

Doesn't said "boom" require oxygen?

I am not an expert on metalic hydrogen, but I was under the impression that it is only 'sort of' stable and could easily be coaxed to expand back to a liquid or gaseous state. The sudden and violent increase in volume and pressure is the source of the 'boom'.

What happens when you suddenly have 100 dtons of fuel in a 1 dton tank?

 

[Zembar]

Any container capable of maintaining the pressures and temperatures needed would probably take a few hits, but I see your point. Even if according to the wikipedia article, it's actually only about nine times more dense than "standard hydrogen", which is admittedly about as loosely defined as you can get. (since lhyd is very roughly 1/700 as dense as hydrogen at 0c/one atmosphere). 9dtons in a 1dton tank is just as bad.

On that note, wouldn't lhyd face the same problem?

To get back more on topic; when making a system using it, it would be neat to take into account the mentioned energy gained simply from converting the hydrogen to a liquid or gas. Perhaps making the PP process the fuel twice for energy.

-- Zembar

 

[far-trader]

I figure whatever new whiz-bang golly-gee fangled tech you want to introduce to the rules, is actually how the rules already work

So, you figure Lhyd can be stored more efficiently as a metastable metallic compound? Well of course it can. The Imperium has been doing it for thousands of years.

So, you think the process of converting the state of the Lhyd will produce energy? Sure, that's already factored into the fantastic efficiency of the Powerplant. Did you think the over 100% efficiency was magic?

Anyway, it's kind of a "what, me worry" attitude but it saves redesigning every frakkin ship in the 'verse and adjusting every rule that changes because of it. The dominoes are all lined up. If you change the fuel density, the whole game will start to unravel or need changing. Well, more so than it does already

 

[far-trader]

Oh, and as for needing oxygen to burn/explode and there being none in space. Most ships are mostly oxygen All those non-fuel spaces are oxygen rich.

And no, I don't believe in the stupid "before battle ships routinely depressurize" hooey for a lot of reasons. But that's another topic I've addressed before

 

[ChalkLine]

Isn't Hydrogen a poor choice for fusion? It gives off a huge amount of neutrons, so you irradiate everything or carry around tons of shielding.

I've heard Helium3 is a better choice, although you can't crack it from water.

 

[Brian Blank]

I figure whatever new whiz-bang golly-gee fangled tech you want to introduce to the rules, is actually how the rules already work

So, you figure Lhyd can be stored more efficiently as a metastable metallic compound? Well of course it can. The Imperium has been doing it for thousands of years.

So, you think the process of converting the state of the Lhyd will produce energy? Sure, that's already factored into the fantastic efficiency of the Powerplant. Did you think the over 100% efficiency was magic?

Anyway, it's kind of a "what, me worry" attitude but it saves redesigning every frakkin ship in the 'verse and adjusting every rule that changes because of it. The dominoes are all lined up. If you change the fuel density, the whole game will start to unravel or need changing. Well, more so than it does already

Actually, what I was thinking would only change how much fuel the ship could carry not to mention you would need another cute little gadget to process the LHyd and turn it into Metallic Hydrogen. Power plant efficency would stay the same, you get a 1Mw generator it still stays at 1Mw.

It might also be something that a TL 16+ civilization would use say maybe with Antimatter Powerplants

 

[Anthony]

Actually, what I was thinking would only change how much fuel the ship could carry not to mention you would need another cute little gadget to process the LHyd and turn it into Metallic Hydrogen. Power plant efficency would stay the same, you get a 1Mw generator it still stays at 1Mw.

It's probably easier to add fuel reclamation technology. One megawatt-year is 3.16*10^13 joules; dividing by c^2 we get 0.35 grams. Fusing hydrogen into helium converts 0.71% of the mass of fuel into energy, so the natural base burn rate for a 1 MW power plant is 50 grams of hydrogen per year, and for a 250 megawatt power plant is 12.5 kilograms per year. Assuming a 25% efficient reactor, that's still only 50 kilograms per year, which is basically negligible.

 

[atpollard]

It's probably easier to add fuel reclamation technology. One megawatt-year is 3.16*10^13 joules; dividing by c^2 we get 0.35 grams. Fusing hydrogen into helium converts 0.71% of the mass of fuel into energy, so the natural base burn rate for a 1 MW power plant is 50 grams of hydrogen per year, and for a 250 megawatt power plant is 12.5 kilograms per year. Assuming a 25% efficient reactor, that's still only 50 kilograms per year, which is basically negligible.

... hence the ancient (but no less valid) position that most of the hydrogen 'fuel' must be used for something other than fusion. Cooling is the most popular answer, followed closely by a 'hydrogen bubble' in jump space.

For what it may be worth, the old T5 previews talk about the fusion power plant/drive unit for small craft being completely sealed with the fuel inside replaced as part of the annual maintenance. Marc appears to be aware of the mass-power conversion data.

 

[Anthony]

... hence the ancient (but no less valid) position that most of the hydrogen 'fuel' must be used for something other than fusion. Cooling is the most popular answer, followed closely by a 'hydrogen bubble' in jump space.

Well, it's a solution for the jump-drive case. It's not a solution for power plant fuel (figuring that the M-drive is a total conversion thruster works out to 2% of ship's mass per week at 1G, which is at least within the ballpark for canon fuel consumption, assuming the drive isn't used 100% of the time).

 

[G. Fieendish]

Well, given that Metallic Hydrogen can carry a current, how about using it as a "backup" battery/capacitor.....

 

[atpollard]

Well, it's a solution for the jump-drive case. It's not a solution for power plant fuel (figuring that the M-drive is a total conversion thruster works out to 2% of ship's mass per week at 1G, which is at least within the ballpark for canon fuel consumption, assuming the drive isn't used 100% of the time).

If I understand this comment correctly, then I somewhat disagree. Maneuver drives are 100% reactionless hand-wave since the MW to 'power' them could easily be derived from solar cells, batteries or any other conventional source (a diesel engine). Thus the fuel is not used as part of any conservation of momentum, but just an ‘inefficient’ fusion reactor.

If I misunderstood your comment, then ignore everything I just said.

 

[Anthony]

If I understand this comment correctly, then I somewhat disagree. Maneuver drives are 100% reactionless hand-wave since the MW to 'power' them could easily be derived from solar cells, batteries or any other conventional source (a diesel engine).

There is nothing in Book 2 or High Guard to contradict the idea that M-drives use fuel, and in fact Beltstrike has rules for fuel use (they're odd rules, but they're rules), not to mention that in first edition high guard M-drives were fusion drives and could be used as weapons. It's clear from CT sources that contragravity doesn't use fuel, but M-drives are not CG.

 

[far-trader]

Actually, what I was thinking would only change how much fuel the ship could carry...

But what you don't appear to see is how much even that changes the game. If the ship can go further with the same fuel, or has the same range with less fuel that means more ship (a lot more ship perhaps) may be dedicated to revenue or armament.

So trade ships are suddenly much more profitable and war ships are suddenly much more deadly.

It changes the game fundamentally. None of the original ship designs will make any sense. Little of the OTU will make any sense. Any YTU based on the OTU will also make little sense.

Not that it's a bad way to go. I'm just saying it won't be the OTU. It won't be most peoples MTU. And it will require a lot of thinking and working of consequences to make YTU work with such a difference.

 

[aramis]

Careful design of "2-week" merchantmen under MT, with maybe 1 day of weapons power, can be far more profitable than a comparable 4-week design.

Especially since, under Bk5 or MT, fuel for the PP is significant.

Jump fuel rates, however, can be even more profound.

Here's the way I see how the effects are going to be:

1) Build a dirt cheap merchantman with no passengers, no installed weapons (but with 2 HP if 200+Td, 1 at 100Td), no carried craft, at 100,200, 400, and 800 Td
2) multiply cargo tonnage by Cr1000
3) Figure 1 load of fuel and 2 weeks of salaries and LS
4) subtract #3 from #2.
5) if #4 is more than 1/480th the purchase price, she's profitable on carriage alone.
6) refigure using Cr1200/Td of cargo to a maximum of 100Td... this is a reasonable spec profit margin under Bk7, the most conservative of the trade systems on average value per ton. (Actually, I use Cr1300/Td, which is closer to the median for Bk7, IME). But since I use T20, i usually wind up with better than that...
7) subtract #3 from #7; and compare as per step 5.

 

[Brian Blank]

But what you don't appear to see is how much even that changes the game. If the ship can go further with the same fuel, or has the same range with less fuel that means more ship (a lot more ship perhaps) may be dedicated to revenue or armament.

So trade ships are suddenly much more profitable and war ships are suddenly much more deadly.

It changes the game fundamentally. None of the original ship designs will make any sense. Little of the OTU will make any sense. Any YTU based on the OTU will also make little sense.

Not that it's a bad way to go. I'm just saying it won't be the OTU. It won't be most peoples MTU. And it will require a lot of thinking and working of consequences to make YTU work with such a difference.

Dan,
You are correct. A Merchant ship would be able to carry more cargo, or a Warship more missles ( Macross comes to mind right now) and it would unbalance the game a bit. Maybe technology like that deserves a place in the Far, Far Future or in experimental areas like Antimatter is treated in the OTU.

Did Marc ever say if Fusion power in Traveller was Hot Fusion or Cold Fusion ( jury is still out on that one, I know)? I seem to remember that Fusion+ in T4 was cold fusion.