An interesting factoid, amount of hydrogen in water vs. LHyd

[actionman]

Carrying water for later use as reserve fuel in cargo is a solid idea, especially if you have to jump through a system where you can't or don't want to refuel normally. Tanks of water (or containers of ice) are simple cargo.

However, to make the jump that has to be processed and the actual fuel tanks filled up with Hydrogen. It doesn't take THAT long to turn water into Hydrogen and oxygen - ocean refuelling typically takes 1D6 hours, so using cargo water would only take about the same time, although that gives unrefined fuel, so there is also the fuel processor time if you want refined fuel. But those are normal considerations.

Methane is possible, but standard ships are set up to scoop hydrogen or pump water and electrolyse it. The equipment to allow that won't allow you to extract hydrogen from Methane or Ammonia. So you would need purpose built methane scooping and processing equipment.

On the other hand, this isn't exotic technology. If you want to designate a fuel scoop or processor as a Methane one, go for it. Might as well say that it has the same mass, volume and cost as a water one. And maybe it would be possible to build a unit that combines both machines, using common parts such as the output that liquifies the hydrogen. Maybe 180% of the mass, volume and cost of a water refiner?

And the oxygen could be used to replenish life support systems.

 

[actionman]

I assume a fuel processor can handle water and methane as gas giants have both.

At Imperial TL's I'd wager it's simple.

 

[actionman]

to make the jump that has to be processed and the actual fuel tanks filled up with Hydrogen.

Friendship is magic and so are jump drives. It would be a lot easier to make things plausible if we knew how jump drives are supposed to use their hydrogen "fuel".

 

[Galadrion]

Methane is possible, but standard ships are set up to scoop hydrogen or pump water and electrolyse it. The equipment to allow that won't allow you to extract hydrogen from Methane or Ammonia. So you would need purpose built methane scooping and processing equipment.

By TL9 or so, it probably is quite possible, even for standard fuel processors. After all, depending on the gas giant (or outer system planet) you're scooping from, methane or ammonia may well be much more readily available, so best to be prepared. And it's already possible, just a technical challenge - a few decades to a century's worth of dedicated research and development should be able to make it more feasible.

 

[actionman]

 

[Sigtrygg]

Fuel scooping and purification is another one of those hard science things Traveller does so well by completely ignoring the realities.

Somehow with no purification plant but with fuel scoops you can get unrefined fuel from gas giant atmospheres, dipping world oceans, or mining ice. Rather than water these liquids and solids could be hydrocarbons or ammonia and the like.

Somehow you can fill your fuel tanks with unrefined fuel but have space to convert it all into refined fuel, in the same full fuel tank.

Friendship is magic and so are jump drives. It would be a lot easier to make things plausible if we knew how jump drives are supposed to use their hydrogen "fuel".

We do, MWM wrote a definitive article about it which is in JTAS 24, MgTJTAS 2.

 

[Condottiere]

What's one more elephant?

 

[MarcusIII]

I assume a fuel processor can handle water and methane as gas giants have both.

RAW says they can in same section as skimming for unrefined. Filling up on any planet with has a hydro score

 

[MarcusIII]

Friendship is magic and so are jump drives. It would be a lot easier to make things plausible if we knew how jump drives are supposed to use their hydrogen "fuel".

Jump bubble in some rules. It is used too fast for ANY energy production so its just ejected into space to make the barrier between J space and the ship.

 

[Condottiere]

In Tee/Five, it's just one possible variant.

If I recall correctly, Collectors don't require hydrogen for jumping.

 

[shirgall]

Of the three (water, methane, and hydrogen) the only thing better than water's 111g per displaced Liter of Hydrogen (and liquid Methane's 106g) would be solid methane (at 90 Kelvin!) at 130g which is a real pain to work with.

 

[hopsnbaer]

Jump bubble in some rules. It is used too fast for ANY energy production so its just ejected into space to make the barrier between J space and the ship.

I hate that version.

 

[MarcusIII]

I hate that version.

it's about the only version that holds water (pun intended)

 

[hopsnbaer]

it's about the only version that holds water (pun intended)

I get it. It just seems dumb to me. I am sticking with the @actionman magic version IMTU.

 

[actionman]

I get it. It just seems dumb to me. I am sticking with the @actionman magic version IMTU.

Actionmagic.

 

[actionman]

Jump bubble in some rules. It is used too fast for ANY energy production so its just ejected into space to make the barrier between J space and the ship.

True and true. But, somebody just made that up at some point to put a bandaid on this massive issue, and I've never accepted it.

 

[actionman]

We do, MWM wrote a definitive article about it which is in JTAS 24, MgTJTAS 2.

Ok here we go:

"When the jump drive is activated, a large store of fuel is fed through the ship power plant to create the energy necessary for the jump drive." JTAS 24 pg. 36.

So the ship's power plant processes tons of LHyd in an extremely short time to charge the jump capacitors, which can also be charged by solar power.

"Some alternate systems make use of solar power generators (which operate much more slowly)... Once power is generated, it must be stored until the instant of jump. Capacitors or large fast-discharge batteries fit this requirement." pg. 35.

So, for some reason ships don't charge their capacitors with their fusion power plants, and somehow the power plant processes tons LHyd almost instantly.

But, this explanation has a shred of plausibility, which is far better than the jump bubble nonsense.

This canon explanation eliminates the need for jump fuel since ships could simply charge their capacitors with their fusion power plants, but the real explanation is "it just does, because without fuel limitations there would be no frontiers or choke points."

My suspension of disbelief escaping from common sense:

 

[actionman]

What's one more elephant?

There are so many elephants we need James Woods saying, "We're gonna need a bigger room."

 

[MarcusIII]

True and true. But, somebody just made that up at some point to put a bandaid on this massive issue, and I've never accepted it.

That's what house rules are for. It's a hard one to come up with something better

 

[swordtart]

Ok here we go:

"When the jump drive is activated, a large store of fuel is fed through the ship power plant to create the energy necessary for the jump drive." JTAS 24 pg. 36.

So the ship's power plant processes tons of LHyd in an extremely short time to charge the jump capacitors, which can also be charged by solar power.

"Some alternate systems make use of solar power generators (which operate much more slowly)... Once power is generated, it must be stored until the instant of jump. Capacitors or large fast-discharge batteries fit this requirement." pg. 35.

So, for some reason ships don't charge their capacitors with their fusion power plants, and somehow the power plant processes tons LHyd almost instantly.

But, this explanation has a shred of plausibility, which is far better than the jump bubble nonsense.

This canon explanation eliminates the need for jump fuel since ships could simply charge their capacitors with their fusion power plants, but the real explanation is "it just does, because without fuel limitations there would be no frontiers or choke points."

My suspension of disbelief escaping from common sense:

If it were a chain reaction it could be credibly quite quick. Normally we chose to run the plant at low levels as we need to run conventional electrics off it. None of it makes any sense, "these aren't the droids we're looking for".