TL-13 long range scout ship

[Outsider]

Originally posted by atpollard:

Simple H-H fusion would seem the most likely candidate.

Certainly the easiest to find fuel for. However, from what I remember H-H fusion requires a 'kick-start' to initiate reaction, needing orders of magnitude more energy then deuterium or tritium fusion. (However tritium fusion, while giving the most power, requires a radioactive fuel - and that doesn't seem to be in keeping the the Traveller concept.) Thus, IMTU, I assume that deuterium is the primary fuel since it's a good middle-ground.

 

[TheEngineer]

AFAIK the Deuterium concentration in Hydrogen is considered to be around 0,015 % everythere.
Anyway it was a good reminder, that the purified fuel is just necessary for jump drives..

The deterium burning of Traveller fusion plant was one try to somehow explain the poor efficiency of those plants.
IMTU hypothetical power plant technology relies on deuterium in order to provide a clean and save fusion...

 

[Plankowner]

Outsider, the Water reference for CT is about refueling from the ocean or another body of water. The water has to be refined (split into H2 and O2) before it can be used as fuel though.

CT pretty clearly states that the PP and Jump Drive use Hydrogen.

Ammonia is also another high-density source of Hydrogen, but it a bit corrosive and toxic, so probably not as good a candidate as Water in the long term. Methane also has a lot of hydrogen.

Using the Hydrogen Densities above, you could have 2 different fuel tanks. One for Fuel (Hydrogen) for 1 Jump and a Reserve Tank (Water) to be processed while in JumpSpace to refill the Hydrogen Tank. Your water tank could be 1/3 of the size of the Hydrogen tank, but still provide the same amount of Hydrogen when separated.

THAT might be an interesting IMTU compromise that would allow longer ranges on those small ships.

 

[chshrkt]

Originally posted by Plankowner:
Using the Hydrogen Densities above, you could have 2 different fuel tanks. One for Fuel (Hydrogen) for 1 Jump and a Reserve Tank (Water) to be processed while in JumpSpace to refill the Hydrogen Tank. Your water tank could be 1/3 of the size of the Hydrogen tank, but still provide the same amount of Hydrogen when separated.

I have no chemical engineering experience to be sure (beyond bonehead organic chem in college), but some how the concept that water has more hydrogen per dTon than straight LHyd is just counter intuitive to this Fine Arts major.

 

[Outsider]

Originally posted by Plankowner:
Outsider, the Water reference for CT is about refueling from the ocean or another body of water. The water has to be refined (split into H2 and O2) before it can be used as fuel though.

CT pretty clearly states that the PP and Jump Drive use Hydrogen.

Yes, agreed. And the hydrogen (and indeed deuterium) comes from the aforementioned water.

Using the Hydrogen Densities above, you could have 2 different fuel tanks. One for Fuel (Hydrogen) for 1 Jump and a Reserve Tank (Water) to be processed while in JumpSpace to refill the Hydrogen Tank. Your water tank could be 1/3 of the size of the Hydrogen tank, but still provide the same amount of Hydrogen when separated.]

This is essentially how it works already IMTU; the water is processed to fill up the L-H2 tanks for the jump drives, with the "normal" water cycling through the reactor's heat exhanger. The reactor (I always envisage a tokamak type) doesn't need to be running constantly, except while in jump. In normal space power is usually taken from capacitor banks, with the reactor firing up when needed to top them up. Constant acceleration or manoeuvring would require more frequent top-ups, or indeed constant reactor power. I don't use a specific rule to determine that, but judge by rule-of-thumb. MTU is more role-play than wargame oriented, so that works for me.

 

[atpollard]

Originally posted by chshrkt:
I have no chemical engineering experience to be sure (beyond bonehead organic chem in college), but some how the concept that water has more hydrogen per dTon than straight LHyd is just counter intuitive to this Fine Arts major.

Try this analogy.

Styrofoam and Milk jugs are both made from similar stuff (mostly hydrogen and carbon), but sytrofoam is naturally more fluffy. A 1 meter cube of styrofoam would weigh less than a 1 meter cube of solid milk jug plastic. One kilogram of styrofoam would form a bigger cube than one kilogram of milk jug plastic.

Liquid Hydrogen is naturally fluffy (like styrofoam). Liquid water is naturally heavy (like plastic).

Hope that helps (or at least does not make it any worse).

 

[chshrkt]

Fluffy Hydrogen?
.
.
.
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I now have a name for our new kitten! (Much better than 'Five')

But seriously, I had no idea that was the case. Adding an ingredient to something to make the atoms 'densify' makes sense I guess, more covalent bonds to pack 'em in tighter or whatever. I guess water, since being an uncompressible liquid at room temperature, would be better (i.e. hold more hydrogen atoms per dTon) than say, liquid methane?

I sure wish I had paid more attention to this stuff 20 years ago! Who knew it would be so critical to my life now? lol

 

[atpollard]

Places like NASA are working on some really funky molecules that can pack even more hydrogen into a smaller space and quickly release it. This is one of those areas where reality will soon leave fantasy in the dust.

 

[TheEngineer]

Hi !

Water is just slightly better than liquid methan (guess H content is around 105 kg H per kiloliter).
Anyway compressibility should be in a similar range, as incompressibility is a defining property of a liquid

In the NASA context I recently read something about SLUSH-hydrogen, which should have a 20% higher density than regular LHyd....

regards,

TE