Low Tech vs Interstellar societies...

[Enoki]

Big feature that should factor in is allowing for multi fuel use such as gas, alcohol and other hydrocarbons. For or ag worlds they might grow some of their fuel.

Haven’t done it yet but plan on sticking players with multi fuel use of wine and cologne. Desperate times…

Major reason for limited deployment of ICE as a product of IND worlds is the specific UWP impact on engines. Different gravity, air density, taint, hydrographic humidity and local fuel sources makes each world nearly unique and requiring different IC/prop/jet engine characteristics for economic function.

Fusion/electric and grav is desirable simply due to portable use.

On Ag worlds, anhydrous ammonia would be a great choice as it likely would be widely used as a fertilizer so farmers could run their machinery on a common fuel with the fertilizer they buy and use. Alcohol and biodiesel are also good choices on such a world.

On any world with lots of organic stuff growing on it, methane would be readily available and might be the fuel of choice.

 

[Spinward Flow]

methane would be readily available and might be the fuel of choice.

It certainly seems to have "caught on" in the chemical rocketry industry, after "someone (else)" finally tried it ...

 

[Condottiere]

Assuming we can use methane, ethanol, water, ammonia, or whatever, as unprocessed fuel, do we adjust the percentages, considering hydrogen density, lower?

 

[Spinward Flow]

Assuming we can use methane, ethanol, water, ammonia, or whatever, as unprocessed fuel, do we adjust the percentages, considering hydrogen density, lower?

Best answer is ... "it's complicated" ... because each feedstock source has different binding energies for the hydrogen in the molecules. Some, like ammonia, will actually be able to increase the amount of hydrogen contained within a unit of volume because of how the hydrogen atoms are bound within those molecules while they're not organized as H₂ molecules. A tank of ammonia contains about 1.5x the number of hydrogen "components" per unit of volume compared to an identical tank of H₂ (for example). Problem is, the process of making/generating ammonia is endothermic, so you have to put energy IN before you can get ammonia OUT for transportation/use of the energy stored in the ammonia.

Gets back to the point I made earlier ... every time you "convert" energy from one form to another, you aren't going to be doing so at 100% efficiency (because: Three Laws of Thermodynamics).

When you've (literally) got nothing better ... you use what you have, no matter how (net) inefficient the energy supply chain is.
Reciprocating piston steam power is wastefully inefficient compared to turbine steam power ... but if all you can manufacture are pistons, then you use what you've got (which in Traveller terms is a tech level limitation). You use pistons to convert thermal energy into linear mechanical energy, then convert again into angular rotary energy ... and so on and so forth ... until finally reaching the end of the sequence resulting in useful work (of whatever variety is needed).



As far as starship fuel purification plant processing goes ... the rules are substantially agnostic on the question of unrefined fuel sources. This then leaves it as a question for Referees to adjudicate whether or not the fuel purification plant installed on YOUR starship can "strip" hydrogen from a wide variety of liquid and gaseous sources of "raw" chemistry found in nature.

My own assumption would be similar to that of LBB5.80 in that streamlined craft can access liquid water (lakes, oceans) under atmosphere, so the fuel scoops in streamlined craft include the capacity for liquid "unrefined fuel" intake (regardless of chemistry, albeit within limits). Partially streamlined craft, which are limited to fuel scooping from the outer atmospheric layers of gas giants, would be able to deal with gaseous/heated into plasma by orbital velocity aerobraking maneuvers fuel scooping, but wouldn't be able to handle liquid state intakes.



So the best answer to your question is ... IT DEPENDS ... on a lot of variables, including environment the unrefined fuel is being gathered from and the "power plant" system (chemical or fusion) it needs to be routed through to generate the desired levels of energy needed for applications. Chemistry ... is complicated ... especially if you don't have "the right kind of equipment" to do it with.

 

[Condottiere]

Best answer is ... "it's complicated" ... because each feedstock source has different binding energies for the hydrogen in the molecules. Some, like ammonia, will actually be able to increase the amount of hydrogen contained within a unit of volume because of how the hydrogen atoms are bound within those molecules while they're not organized as H₂ molecules. A tank of ammonia contains about 1.5x the number of hydrogen "components" per unit of volume compared to an identical tank of H₂ (for example). Problem is, the process of making/generating ammonia is endothermic, so you have to put energy IN before you can get ammonia OUT for transportation/use of the energy stored in the ammonia.

Gets back to the point I made earlier ... every time you "convert" energy from one form to another, you aren't going to be doing so at 100% efficiency (because: Three Laws of Thermodynamics).

When you've (literally) got nothing better ... you use what you have, no matter how (net) inefficient the energy supply chain is.
Reciprocating piston steam power is wastefully inefficient compared to turbine steam power ... but if all you can manufacture are pistons, then you use what you've got (which in Traveller terms is a tech level limitation). You use pistons to convert thermal energy into linear mechanical energy, then convert again into angular rotary energy ... and so on and so forth ... until finally reaching the end of the sequence resulting in useful work (of whatever variety is needed).



As far as starship fuel purification plant processing goes ... the rules are substantially agnostic on the question of unrefined fuel sources. This then leaves it as a question for Referees to adjudicate whether or not the fuel purification plant installed on YOUR starship can "strip" hydrogen from a wide variety of liquid and gaseous sources of "raw" chemistry found in nature.

My own assumption would be similar to that of LBB5.80 in that streamlined craft can access liquid water (lakes, oceans) under atmosphere, so the fuel scoops in streamlined craft include the capacity for liquid "unrefined fuel" intake (regardless of chemistry, albeit within limits). Partially streamlined craft, which are limited to fuel scooping from the outer atmospheric layers of gas giants, would be able to deal with gaseous/heated into plasma by orbital velocity aerobraking maneuvers fuel scooping, but wouldn't be able to handle liquid state intakes.



So the best answer to your question is ... IT DEPENDS ... on a lot of variables, including environment the unrefined fuel is being gathered from and the "power plant" system (chemical or fusion) it needs to be routed through to generate the desired levels of energy needed for applications. Chemistry ... is complicated ... especially if you don't have "the right kind of equipment" to do it with.

But, with fusion reactors the energy aspect has much less relevance, and minimizing jump fuel percentages greater.

If it's a question of an energy requirement for any transformation, saving volume, for even non jump applicable vehicles, would make it a worthwhile endeavor.

Of course, the other half of the operation being possibly misjumping, could just be the cost of doing business.

 

[atpollard]

Just a quick note to anyone interested:

The Electric vs Hydrogen Car discussion was moved to its own topic …
Electric and Hydrogen Vehicles [link]

 

[Rupert]

Best answer is ... "it's complicated" ... because each feedstock source has different binding energies for the hydrogen in the molecules. Some, like ammonia, will actually be able to increase the amount of hydrogen contained within a unit of volume because of how the hydrogen atoms are bound within those molecules while they're not organized as H₂ molecules. A tank of ammonia contains about 1.5x the number of hydrogen "components" per unit of volume compared to an identical tank of H₂ (for example). Problem is, the process of making/generating ammonia is endothermic, so you have to put energy IN before you can get ammonia OUT for transportation/use of the energy stored in the ammonia.

An fairly extreme example of that is water. By volume, a displacement ton of liquid hydrogen has 1 tonne of hydrogen (by definition). The same volume of water (14 cubic metres) contains 14/9 = ~1.556 tonnes of hydrogen. So by volume it's a considerably more compact way of storing hydrogen, but it carries a huge mass penalty (x9 the mass per unit mass of hydrogen) and it takes a lot of energy to persuade the oxygen to let go of the hydrogen.

 

[Black Vulmea]

You know what I like? A TU where all of these options are in use, existing side-by-side system by system.

Different worlds using different sources of energy, with different solutions to the same problems of transport, infrastructure, power storage, et al.

Remember that TL 7 world I mentioned upthread? Its highport is tethered to a space elevator and it produces chemical rocket-powered and solar sail-propelled spacecraft.

Are these technologically inferior to fusion-powered and grav-propelled craft? Obviously. There is, however, a cultural conservatism that makes them desirable and preferable to Valisans. It's also desirable to some offworlders as well, in the same way classic cars and runabouts are to our culture, producing a small but thriving market for Valisan spacecraft on its TL B neighbors.

One-size-fits-all thinking is the opposite of what Traveller tech levels mean to me. The progression of technological advances cataloged by tech level isn't inevitable everywhere all the time. Available resources, cultural practices, trade limitations, world and system history, sophont variety: disparities abound for as many different reasons as the referee chooses to think of.

 

[Badenov]

An fairly extreme example of that is water. By volume, a displacement ton of liquid hydrogen has 1 tonne of hydrogen (by definition). The same volume of water (14 cubic metres) contains 14/9 = ~1.556 tonnes of hydrogen. So by volume it's a considerably more compact way of storing hydrogen, but it carries a huge mass penalty (x9 the mass per unit mass of hydrogen) and it takes a lot of energy to persuade the oxygen to let go of the hydrogen.

Wait, this has confused me. If a dton of water, 14m^3, contains more Hydrogen than 1 dton of Liquid Hydrogen, why do we do the liquid hydrogen thing? It can't be the energy, we expend the energy to convert it into fuel regardless, it's just a matter of timing. Either scoop and convert immediately, or scoop and convert as needed. Water is certainly less of a catastrophe if the tank leaks or a mishap happens, it seems like that'd make water the preferred storage method.

 

[spank]

Wait, this has confused me. If a dton of water, 14m^3, contains more Hydrogen than 1 dton of Liquid Hydrogen, why do we do the liquid hydrogen thing? It can't be the energy, we expend the energy to convert it into fuel regardless, it's just a matter of timing. Either scoop and convert immediately, or scoop and convert as needed. Water is certainly less of a catastrophe if the tank leaks or a mishap happens, it seems like that'd make water the preferred storage method.

It takes time to convert the water. Jump uses an incredible amount of fuel, and need most of it right now!

 

[Condottiere]

It would be more a matter of storage.

Ifm for exammple, you're doing multiple parsec jumps with a monoparsec jump drive, you can squeeze in more fuel in the reserve tanks.

 

[Rupert]

Wait, this has confused me. If a dton of water, 14m^3, contains more Hydrogen than 1 dton of Liquid Hydrogen, why do we do the liquid hydrogen thing? It can't be the energy, we expend the energy to convert it into fuel regardless, it's just a matter of timing. Either scoop and convert immediately, or scoop and convert as needed. Water is certainly less of a catastrophe if the tank leaks or a mishap happens, it seems like that'd make water the preferred storage method.

Because water is a really heavy way of storing hydrogen, and while most version of Traveller ignore mass most of the time, that's going to be an issue. Also, when you need the hydrogen you have to get it out of the water, and takes a lot of energy, and also time.

IMTU water, ammonia, methane, and so on are gathered and stored, but only for as long as it takes to run them through a fuel 'purifier'. The resulting hydrogen is then stored, along with anything else that's useful (though if that's in more quantity than is required for the ship's system, the ship will need extra tankage). I assume that the tanks are suitable for storing multiple types of gas and liquid, that the pumps are also multi-fluid rated, and so on.

When using HEPlaR you still need hydrogen as a propellant because other fluids have higher molecular mass, and thus lower specific impulse.

 

[ady]

You know what I like? A TU where all of these options are in use, existing side-by-side system by system.

Different worlds using different sources of energy, with different solutions to the same problems of transport, infrastructure, power storage, et al.

Remember that TL 7 world I mentioned upthread? Its highport is tethered to a space elevator and it produces chemical rocket-powered and solar sail-propelled spacecraft.

Are these technologically inferior to fusion-powered and grav-propelled craft? Obviously. There is, however, a cultural conservatism that makes them desirable and preferable to Valisans. It's also desirable to some offworlders as well, in the same way classic cars and runabouts are to our culture, producing a small but thriving market for Valisan spacecraft on its TL B neighbors.

One-size-fits-all thinking is the opposite of what Traveller tech levels mean to me. The progression of technological advances cataloged by tech level isn't inevitable everywhere all the time. Available resources, cultural practices, trade limitations, world and system history, sophont variety: disparities abound for as many different reasons as the referee chooses to think of.

That's the way I see it as well - every planet the Travellers visit (based on the UPP) is different from the last, technology, environment, culture, the way they wear their hats, etc. It's one of the main reason to travel, I find, for the variety. I like reading Jack Vance's novels because of this, because in the Dying Earth stories, every village the hero visits has a different technology and prefered way of doing things, that they think is the RIGHT way. With the slow speed of communication and space travel, I imagine each world to be something new and unique. If every world in the imperium is a modern California that just uses TL15 fusion and grav for everything, it means glossing over much of the variety the UPP suggests and makes me wonder what the point in even travelling to new worlds is. Technology is a good way to suggest the background history, environment, culture, economics and beliefs of the world, through what they are prefering to use and why they use it.

 

[Spinward Flow]

You know what I like? A TU where all of these options are in use, existing side-by-side system by system.

Different worlds using different sources of energy, with different solutions to the same problems of transport, infrastructure, power storage, et al.

There is something to be said for this approach of increased granularity concerning tech levels.
The downside is ... it involves more bookkeeping in order to keep everything recorded.

Probably the best way to think of it is that the UWP tech level is just a first order approximation "average" of the technologies in use at a mainworld, but a more detailed analysis will "explain" how that average value is arrived at (and show deviations from the mean value).

Such an approach increases the "texture" of the setting by allowing tech levels to be more "variable" than just what's captured by a single integer for ... everything.

 

[Enoki]

My view on the hydrogen issue is that,

The storage problem has been solved in some way like technology exists to make a tank that is both cryogenic like a dewar (thermos bottle) and nonporous to hydrogen like a material that has had its molecular or atomic structure densified to a point that hydrogen atoms can't leak through it. Both are possible if not technically on a mass manufacturing level feasible today.

That hydrogen use and production is widespread enough that a fuel conversion / purifier system is available to crack many common molecules with lots of hydrogen in them like methane, ammonia, or water. These are common enough that you can expect there's a planet or moon in just about every system you encounter that has one of these on it. The machine is simply set up to crack the correct molecule, and you get lots of hydrogen. With water or ammonia, you also get oxygen or nitrogen which you likely need for ship operations (breathing and pressurizing systems). With methane you get carbon as a residual and likely just dump it overboard as solid waste. Or you might use it as a filtration media for water or air on the ship in the form of activated carbon.

In fact, it might even be desirable you find and process all three for those reasons. The fuel processor might be set up as a triple plant that can handle any one of the three or do all three simultaneously.

 

[Spinward Flow]

The storage problem has been solved in some way like technology exists to make a tank that is both cryogenic like a dewar (thermos bottle) and nonporous to hydrogen like a material that has had its molecular or atomic structure densified to a point that hydrogen atoms can't leak through it. Both are possible if not technically on a mass manufacturing level feasible today.

Technological advancement will solve the problem "someday" in the future ... it just hasn't yet (in the real world).

That hydrogen use and production is widespread enough that a fuel conversion / purifier system is available to crack many common molecules with lots of hydrogen in them like methane, ammonia, or water.

The "waste" chemistry of carbon, nitrogen and oxygen from those refining processes are ALL useful in the context of life support systems, particularly in hostile environments that do not support native biospheres hospitable to (organic) sophont life.

What makes the fuel purification plant "practical" as a means to process those chemical feedstocks in order to separate the hydrogen from the other "waste" chemical elements is ... the fusion power plant. Once the fusion power plant makes the "cost of energy a marginal factor" then all kinds of "energy intensive" chemical refining options become practical, rather than prohibitively expensive (to the point of being "wasteful" however you want to define it).

Fusion <-> Hydrogen in economic terms is a bit like the age old question of Chicken vs Egg.

 

[Black Vulmea]

If every world in the imperium is a modern California that just uses TL15 fusion and grav for everything, it means glossing over much of the variety the UPP suggests and makes me wonder what the point in even travelling to new worlds is.

Satori.

The beating heart of science fiction is speculating about the future, of exploring possibilities, including roads not taken for whatever reason. That extends beyond physical science and technology to biological and social sciences as well.

Frex, I may have missed it, but did anyone bring up the notion of hydrogen as biofuel? Hydrogen is a waste product of decomposition, so how about a world where freestanding water is protected for religious reasons - no wilderness refueling, captain - that instead 'farms' its hydrogen from solid waste?

When you bring together the range of potential star systems out there with human populations that existed in isolation from one another for tens of millennia as well as completely alien species, the very last thing you should get is a Third Imperium that resembles a DMV simulation - I'm lookin' at you, GT.

 

[Condottiere]

Fuel bladder seems operatively impermeable to spacecraft fuel, processed or otherwise.