Voyager & Fuel

[Baffalo]

Alright, I was reading through the thread "Replace Voyager with the Enterprise-D" and I got to thinking. The entire purpose of the Warp Core is to channel the flow of matter and anti-matter to create a stream of high-energy plasma. Ok, fairly good so far. Got that. The problem I'm having is, if Starfleet uses matter and anti-matter, then why the hell does any ship ever need to stop for fuel EVER?

Here's my reasoning: The Bussard collectors mounted to the front of every starship is designed primarily for the collection of deuterium floating in interstellar space. While the void between stars might be barren, the flow of deuterium from stars would be enough to at least facilitate a healthy supply, meaning a ship could pass through and collect an absolute ton of deuterium just floating around loose in a star system. So that would (likely) cover it, so that just leaves anti-deuterium, right?

Well... the problem with that is that antimatter is, inherently, not going to be found floating around. Now, here on Earth, we produce our own antimatter in two ways: nuclear reactions (where small anti-particles are released and destroyed) and particle accelerators. Now, naturally, the one that's produced naturally decays so fast that it's essentially unusable, while the other requires a huge facility to produce. Regardless, by the 24th century I'm sure they've got ways of storing enough anti-matter after producing it that they're not absolutely pressed for that at any given time.

So my question is, why does Voyager make it a point of stopping for fuel? Surely they can obtain enough in transit to keep going. And if they have the fuel covered, and they have replicators, then why would they need to stop or even limit fuel consumption? Is this just a plot device? Or is it a legitimate concern?

[Napoleon the Clown]

They can only carry a finite supply of anti-matter, and as much energy as you can get out of the reaction it will never be 100% useable energy. Also, star ships are massive, even one the size of Voyager. The warp field likely consumes phenomenal amounts of energy to get up and keep stable...

We just don't know how much energy Voyager needs in the space of a day of minimal activity, much less when they have to have their shields up and using weapons, or going to warp. They fully expected to take something in the order of 70 years to get home, and they didn't know just how much fighting they'd need to do in the process. I can see justification for avoiding excessive fuel consumption and getting more whenever there's a realistic chance.

[Lord Revan]

While I don't think it's ever addressed in the actual TV series or movies, IIRC in suplementry material (one of the Tech-manuals IIRC) it was explained that the method used to created the anti-matter fuel is energy ineffecient (aka it uses more energy then you could get from the fuel) so it would suggest that replacing the warpdrive anti-matter at fast rate would just create a fuel problem of different sort and that's assuming Voyager is even equipted with Anti-matter production facilities (or at least large scale ones need to elimanate fuel needs for a ship of that size)

basically trading for fuel and making pit stops simply more efficient use of the resources they got and should remember that the replicators aren't "money for nothing" devices either and that's ignoring the need for spare parts that might not be able to be replicated.

You should also remember that Deep Space 9 was using a fusion power source even though Cardassian had access to AM/M reactor tech suggesting there's some limits to that tech.

also when in situation where there's no realistic way of getting support from home, you want you avoid "as long as this 1 thing works perfectly" in your plans as much as humanly possible. remember that Voyager had to plan for a 75 year trip not a 7 year one.

[biostem]

Don't Fed ships have secondary fusion reactors that actually provide a lot of the "everyday" power that the ship needs? If that is the case, then couldn't they focus on collecting usable matter, (deuterium), and converting it into antimatter as needed?

[Lord Revan]

that's assuming they can do onboard in any realistic rate.

Do I need to remind you that we don't know how anti-matter is made in Star Trek only that it can produced in sufficient amount to be used as fuel.

[Napoleon the Clown]

Even if they could create anti-matter with 100% efficiency, they're still not going to be able to actually increase their supplies. They'd need an energy source to make anti-matter at all. Unless they could "mine" it directly, it's just converting energy into a more dense form. Matter/anti-matter reactions aren't this magical thing that somehow bypasses E=MC2.

[SpottedKitty]

Do I need to remind you that we don't know how anti-matter is made in Star Trek only that it can produced in sufficient amount to be used as fuel.

I'm sure I remember coming across a note in one of the Tech Manuals (the TNG one, maybe?) that said, or implied, that any starship with Bussard collectors bolted to the front of the nacelles also had the technobabble mechanisms needed to create antimatter.

Found it — yes, the TNG Tech Manual, near the end of the chapter on the warp drive. The Bussard collectors only work to replenish the deuterium supply, there's an extra big, heavy gadget* that takes a deuterium feed and great big gobs of power in one end, and puts out a trickle of antimatter at the other end. And it's horribly inefficient; the book quotes ten units of deuterium needed to create one unit of antimatter. I think the only way this thing would work to actually extend the ship's range would be if you were lucky enough to find a really thick patch of interstellar gas that you could swoop through repeatedly. Either that or figure out a way to "siphon the tank" of a gas giant planet.

* The gadget rejoices in the name of "Quantum Charge Reversal Device". I think I found a place where the manual writers were hit by a combined looming deadline and running out of coffee...

[Napoleon the Clown]

The name actually kinda makes sense, from the perspective that antiparticles are the opposite charge. I don't recall the quark make-up of antiparticles relative to regular particles, but the name isn't completely absurd. At least, no more so than most of the other technobabble.

But yeah, no way on-ship production could be made feasible. If you wanted to be able to "top off" from stray deuterium you'd want to have an enormous antimatter load. Regular matter is simple to find.

[Baffalo]

*digs out a scratch pad*

I should have done this last night but I was tired when I posed the question. Stupid me.

Ok. Had to go digging but I'm gonna use Mike's original Star Trek power outputs of 1E19 to 1E20 Watts as a baseline.

So for our equations here, let's use 5E19 Watts, or 5E19 J/s.

Now for everyone's favorite equation, E2 = (m0c2)2 + (pc)2

Since we don't know at what velocity the atoms are traveling at when they impact, and since they would be negated simply by impact, we can safely say that p (the momentum) is zero, leaving us with E2 = (m0c2)2, or E = m0c2.

Plugging in our numbers, we get 5E19 J/s = m0(2.99792458E8 m/s)2, leaving us with m0 = 5.56325E2 kg/s, or 556.325 kg/s.

At 14K, elemental hydrogen is a solid. Most likely, it is stored as a solid "powder" or small individual grains, with a density of 0.086 g/cm3, or 8.6E-5 kg/m3. Diving 5.56325E2 kg/s by 8.6E-5 kg/m3 gives us 6.46889535E6 m3/s.

Someone please double check me and make sure I didn't screw this up. Because that's for both feeds combined.

EDIT: I was going somewhere with the hydrogen and lost track, so I deleted it.

[Eternal_Freedom]

The name actually kinda makes sense, from the perspective that antiparticles are the opposite charge. I don't recall the quark make-up of antiparticles relative to regular particles, but the name isn't completely absurd. At least, no more so than most of the other technobabble.

Easy enough: an anti-proton is anti-up-quarks and one anti-down quark. An anti-neutron would be two anti-downs and one anti-up. The charges on the individual quarks/antiquarks are just reversed, it doesn't change the number and type, otherwise you'd have a different particle entirely.

Note: That is going off what I remember from my 3rd year quantum physics module, I may not be correct.

[Borgholio]

Here's the problem I had with the "always looking for fuel" thing. Converting matter to anti-matter uses a shit-ton of fuel for the fusion reactors. So while it might be hideously inefficient, if they had enough fuel there's no reason why they couldn't do it. So why don't they go find a nebula or a gas giant and start siphoning? A nebula could have several solar-masses worth of hydrogen in it. That would be plenty for them to stock up on.

[Batman]

That presupposes that a) the Quantum Charge Reversal Device actually exists, b) Intrepids have one and c) it survived the somewhat bumpy trip to the Delta quadrant intact/in repairable shape. I don't recall it being mentioned anywhere other than the TNG TM.

[Simon_Jester]

Alright, I was reading through the thread "Replace Voyager with the Enterprise-D" and I got to thinking. The entire purpose of the Warp Core is to channel the flow of matter and anti-matter to create a stream of high-energy plasma. Ok, fairly good so far. Got that. The problem I'm having is, if Starfleet uses matter and anti-matter, then why the hell does any ship ever need to stop for fuel EVER?

Because:
1) Deuterium fusion isn't actually drastically less energy-intensive than antimatter reactions; it's about an order of magnitude less. Since deuterium is free and antimatter can only be made under unusual conditions with heavy machinery, it pays to let the ship use deuterium even if that means needing more fuel (measured in kilograms).
2) Antimatter is itself a fuel that has to be manufactured. The ship can only carry so much, and when it runs out it loses its ability to use the warp core.
3) Storing antimatter is inevitably harder than storing mundane deuterium. Therefore, even if antimatter is ten times as powerful a fuel source, kilo for kilo... you end up having to spend ten (or a hundred, or a thousand) times more mass and bulk to store a kilo of antimatter. Therefore you can't store infinite supplies of antimatter fuel aboard ship.
4) Warp travel is handwavy but may be very power-intensive. Even a large supply of antimatter might be run down over the course of hours, days, or months at high warp speed.

Well... the problem with that is that antimatter is, inherently, not going to be found floating around. Now, here on Earth, we produce our own antimatter in two ways: nuclear reactions (where small anti-particles are released and destroyed) and particle accelerators. Now, naturally, the one that's produced naturally decays so fast that it's essentially unusable, while the other requires a huge facility to produce. Regardless, by the 24th century I'm sure they've got ways of storing enough anti-matter after producing it that they're not absolutely pressed for that at any given time.

So my question is, why does Voyager make it a point of stopping for fuel? Surely they can obtain enough in transit to keep going. And if they have the fuel covered, and they have replicators, then why would they need to stop or even limit fuel consumption? Is this just a plot device? Or is it a legitimate concern?

They don't have the means to manufacture antimatter on their own aboard the ship, presumably.

Even if they did, they might have to stop moving in order to do that. They may not be able to pour more antimatter into the warp core's storage while simultaneously running the warp core.

Or they might have the means to synthesize antimatter fuel, but not as fast as they can consume it... in which case sooner or later the tank runs empty and they have to refill it before they can keep going.

Don't Fed ships have secondary fusion reactors that actually provide a lot of the "everyday" power that the ship needs? If that is the case, then couldn't they focus on collecting usable matter, (deuterium), and converting it into antimatter as needed?

Sure. In which case they'd cruise through space collecting deuterium, and stop when they run out of antimatter. Then they'd make more antimatter from the deuterium they collected, using the fusion reactors to power antimatter synthesis. Then they'd get moving again for a while, then stop... lather, rinse, repeat.

Any opportunity to stop by a convenient gas giant (or existing Delta Quadrant fuel depot) could be desirable in that case. Because you could use such a pit-stop to collect a massive amount of deuterium fast, and use it to synthesize an equally massive amount of antimatter.

Let me make up some numbers to illustrate. Suppose the ship's sustainable "collecting fuel" cycle involves spending 100 hours at warp and, say, 400 hours at impulse trying to scrounge up enough fuel for the next 100 hours at warp, via the Bussard scoop.

Now suppose you can spend 100 hours refueling intensively at a gas giant, which is a much higher-density fuel source. Then you travel for 1000 hours at warp continuously, while collecting further deuterium for the next 200 hours with the usual Bussard scoop technique. In 1300 hours of travel in this way, you've covered about five times the distance you could otherwise have covered using your normal fuel cycle.

[In this case I am assuming that stopping for fuel at a fixed location is fifty times faster than scrounging it from interstellar vacuum, which seems pretty reasonable. I am also assuming the ship's "bottleneck" for producing fuel is its ability to scavenge deuterium, not its ability to synthesize antimatter, which may not be true.]

Anyway, if we make certain assumptions, the fuel stops could be very helpful and save a lot of time. Voyager would still have the ability to 'scrounge' fuel, and Starfleet ships could still use their scrounging ability to travel normal distances inside the Federation in a pinch... but for a long range cruise it really helps if you can pick up fuel on the way in convenient, accessible locations rather than foraging en route

Found it — yes, the TNG Tech Manual, near the end of the chapter on the warp drive. The Bussard collectors only work to replenish the deuterium supply, there's an extra big, heavy gadget* that takes a deuterium feed and great big gobs of power in one end, and puts out a trickle of antimatter at the other end. And it's horribly inefficient; the book quotes ten units of deuterium needed to create one unit of antimatter.

Do the collectors work at impulse power? They should since it's totally possible to scoop up hydrogen from interstellar space at sublight speeds.

Now for everyone's favorite equation, E2 = (m0c2)2 + (pc)2

Since we don't know at what velocity the atoms are traveling at when they impact, and since they would be negated simply by impact, we can safely say that p (the momentum) is zero, leaving us with E2 = (m0c2)2, or E = m0c2.

Plugging in our numbers, we get 5E19 J/s = m0(2.99792458E8 m/s)2, leaving us with m0 = 5.56325E2 kg/s, or 556.325 kg/s.

What you have just done is calculate the amount of deuterium that needs to be converted to energy. Deuterium fusion is, more realistically, limited to an efficiency such that you get, oh... about 10^15 joules per kilo of fuel. So the actual amount of fuel required is going to be something like a hundred metric tonnes of deuterium per second to supply the full 10^20 watt power output of the ship.

Alternatively, suppose the ship's power supplies are based on using antimatter at high efficiency. Theoretically, matter/antimatter fuel can get up into the range of... I don't know, 2*10^16 joules per kilo of fuel (half-and-half) would be about 20% efficiency. Roughly. In which case you need 'only' about 5000 kilograms of fuel per second to supply 10^20 watts, or 2500 kilograms of antimatter and 2500 kilograms of matter.

If you can turn 10 kilograms of deuterium into one kilogram of antideuterium, this translates into burning 2500 kilos of deuterium per second directly, and 25000 tons to produce the antimatter to run the reactor... and you still come out ahead, because matter/antimatter reactors are converting mass into energy twenty times as efficiently as a deuterium reaction.

If matter/antimatter reactors are more efficient, this calculation becomes even more skewed in favor of using deuterium to power antimatter converters rather than using it to power a fusion reactor.

If fusion reactors are made more efficient, then the calculation shifts more to favor using the deuterium in the fusion reactor. But frankly that requires that we just drop the whole concept of enthalpy. Deuterium fusion just can't liberate more than a few percent of the total mass-energy of the fuel because you started with four nucleons and end with four nucleons; all you're actually doing is liberating some binding energy that ties those nucleons together.

At 14K, elemental hydrogen is a solid. Most likely, it is stored as a solid "powder" or small individual grains, with a density of 0.086 g/cm3, or 8.6E-5 kg/m3. Diving 5.56325E2 kg/s by 8.6E-5 kg/m3 gives us 6.46889535E6 m3/s.

Someone please double check me and make sure I didn't screw this up. Because that's for both feeds combined.

Denser forms of hydrogen storage exist in principle. One friend of mine likes to play with the idea of metallic hydrogen, which is quite dense, although potentially explosively unstable. But hell, it's Star Trek, having lots of stuff on the ship that explodes when you hit it too hard is par for the course.

The name actually kinda makes sense, from the perspective that antiparticles are the opposite charge. I don't recall the quark make-up of antiparticles relative to regular particles, but the name isn't completely absurd. At least, no more so than most of the other technobabble.

Easy enough: an anti-proton is anti-up-quarks and one anti-down quark. An anti-neutron would be two anti-downs and one anti-up. The charges on the individual quarks/antiquarks are just reversed, it doesn't change the number and type, otherwise you'd have a different particle entirely.

Note: That is going off what I remember from my 3rd year quantum physics module, I may not be correct.

Under the Standard Model, flipping quarks into antiquarks violates the conservation of "baryon number," which is a quantity as fundamental as charge. On the other hand, Star Trek is clearly predicated on the assumption that the Standard Model is very, VERY incomplete as an explanation of what is and is not possible in the universe.

Here's the problem I had with the "always looking for fuel" thing. Converting matter to anti-matter uses a shit-ton of fuel for the fusion reactors. So while it might be hideously inefficient, if they had enough fuel there's no reason why they couldn't do it. So why don't they go find a nebula or a gas giant and start siphoning? A nebula could have several solar-masses worth of hydrogen in it. That would be plenty for them to stock up on.

Nebulae are low-density and it could take a long time to stock up enough deuterium to fill up their tanks. Gas giants are much denser sources and it's less work to fill up the tank. And if you're really lazy you just cruise up to someone else's filler station and barter for existing, pre-refined starship fuel...

[Simon_Jester]

EDIT:

I said 25000 TONS of deuterium required per second once in the above post. That should have been kilograms.

To revisit my assumptions, I'm talking about how much deuterium fuel you need to make enough antimatter to run the matter/antimatter reactor at full power, assuming 10% efficiency of deuterium to antideuterium conversion.

This is not correct. If the ship's full power output is 10^20 watts, and it runs on 20%-efficient matter-antimatter conversion, then they need (to reiterate) 5000 kilograms per second of matter and antimatter. 2500 kilos of deuterium, 2500 kilos of antideuterium...

Or 27500 kilos of deuterium needed total, about 90% of which is being shoved into the fusion reactors to convert matter to antimatter. This still turns out to be more mass-efficient in terms of the amount of deuterium fuel required, assuming you have the technomagic it takes to turn one kilo of deuterium into 100 grams of antideuterium, and a 20% efficient antimatter reactor.

[Borgholio]

Nebulae are low-density and it could take a long time to stock up enough deuterium to fill up their tanks.

True, but they're denser than interstellar space in which we see Voyager spending most of her time. If they really were hard up for fuel, a nebula would be better than nothing.

[Simon_Jester]

Well yes, but going far out of your way to reach such a nebula might be self-defeating. At most, you'd want your course to "slalom" across the galaxy and spend as much time as possible in regions of dense interstellar gas. And it would still make more sense to stop and soak up deuterium from a fixed, high-density source under a lot of very plausible circumstances.

I mean, we don't call it "inefficient" that cars have to stop for a few minutes to refuel for every four to six hours of high speed driving...

[Lord Revan]

btw we know the collectors can be used in impulse speeds as Ent-E used them in Insurrection to gather the plot gas.

[Baffalo]

Simon_Jester, my calculations were done with the assumption that they were using straight hydrogen found floating about in space, with very little (read: ~99.9%) loss in the system. Idealy, you would want a heavy, densely packed anti-matter base because

a) the denser the material, the more material you're slamming together and,
b) optimal storage.

The biggest problem you run into with the production of anti-matter is that it's super easy to produce anti-hydrogen, but what about anti-deuterium? So far, we've only been able to glimpse antihelium in specific laboratory conditions.

The best way... and this is just my thinking, I have no idea how it would work in practice... would be to to take a dense element, such as Iridium (22.56 g/cm3) or Osmium (22.59 g/cm3) and toss antihydrogen at it. I forsee one of two things happening:

1) The destruction of a proton would drop the element down to a new element
2) The destruction of a neutron would reduce the element's atomic weight by 1, creating a different isotope collision

Code: Select all

PARENT ELEMENT  NEUTRON COLLISION	PROTON COLLISION RESULT
-------------------------------------------------------------------------------
Ir 193		Ir 192 HL: 73.83 d	Os 192 Stable
Ir 191		Ir 190 HL: 11.78 d	Os 190 Stable
Os 192 		Os 191 HL: 15.4 d	Re 191*
Os 190 		Os 189 Stable		Re 189*
Os 189 		Os 188 Stable		Re 188*
Os 188 		Os 187 Stable		Re 187 HL: 4.1E10 y
Os 187		Os 186 HL: 2.0E15 y	Re 186*
Os 186		Os 185 HL: 93.6 d	Re 185 Stable
Os 184		Os 183*			Re 183*

* No known isotope exists

That's all assuming that the energy released doesn't just split the atom apart.

[Simon_Jester]

Simon_Jester, my calculations were done with the assumption that they were using straight hydrogen found floating about in space, with very little (read: ~99.9%) loss in the system. Idealy, you would want a heavy, densely packed anti-matter base because

a) the denser the material, the more material you're slamming together and,
b) optimal storage.

This is debateable. (1) depends on how the matter and antimatter are collided. (2) depends on how it is stored- a magnetic bottle containing cryogenic gas might be much safer and more 'optimal' than trying to contain a massive, dense brick of solid anti-osmium. Plus, good luck peeling individual anti-osmium atoms off the brick without having them ricochet all over the place.

The best way... and this is just my thinking, I have no idea how it would work in practice... would be to to take a dense element, such as Iridium (22.56 g/cm3) or Osmium (22.59 g/cm3) and toss antihydrogen at it. I forsee one of two things happening:

1) The destruction of a proton would drop the element down to a new element
2) The destruction of a neutron would reduce the element's atomic weight by 1, creating a different isotope collision

At this point I'd want to refer to the literature...

But more generally, I just used the assumption that the warp core runs on deuterium/antideuterium because that way I could have the fuel used in fusion and antimatter reactors be commensurate. The core idea here is much simpler- that antimatter reactions are or can be so much more efficient than fusion reactions that the given "ten to one" matter to antimatter conversion ratio actually makes it worthwhile to synthesize antimatter rather than run raw hydrogen feedstock through a fusion plant for electrical power.

[Baffalo]

This is debateable. (1) depends on how the matter and antimatter are collided. (2) depends on how it is stored- a magnetic bottle containing cryogenic gas might be much safer and more 'optimal' than trying to contain a massive, dense brick of solid anti-osmium. Plus, good luck peeling individual anti-osmium atoms off the brick without having them ricochet all over the place.

Sorry, I should have specified. I meant that antihydrogen would collide with the Osmium in order to start the reaction. Blah. Anyway, yes, two magnetic bottles would make more sense, but the literature says that the hydrogen and antihydrogen are stored at 13.8K, which is below hydrogen's freezing point. From an energy density perspective, that's better because a solid is much more dense than a gas or liquid.

At this point I'd want to refer to the literature...

But more generally, I just used the assumption that the warp core runs on deuterium/antideuterium because that way I could have the fuel used in fusion and antimatter reactors be commensurate. The core idea here is much simpler- that antimatter reactions are or can be so much more efficient than fusion reactions that the given "ten to one" matter to antimatter conversion ratio actually makes it worthwhile to synthesize antimatter rather than run raw hydrogen feedstock through a fusion plant for electrical power.

Given how much Trek loves to claim they've got science down pat, I wonder if they've somehow mastered quantum tunneling? The reason I ask is because to master quantum tunneling would reduce the raw energy requirements of fusion, similar to what happens in stars, and would make fusion much more efficient from an energy production standpoint. Given that they use Heisenberg Compensators for transporters, I could see the fusion reactors aboard a starship using this to combine Hydrogen 1 and Boron 11 to form 3 Helium 4's, which is the most promising for aneutronic fusion.

I'd run the math but this is theoretical stuff and I have no idea what the energy outputs would be.

[Simon_Jester]

This is debateable. (1) depends on how the matter and antimatter are collided. (2) depends on how it is stored- a magnetic bottle containing cryogenic gas might be much safer and more 'optimal' than trying to contain a massive, dense brick of solid anti-osmium. Plus, good luck peeling individual anti-osmium atoms off the brick without having them ricochet all over the place.

Sorry, I should have specified. I meant that antihydrogen would collide with the Osmium in order to start the reaction.

Your osmium target will be hellaciously radioactive within short order, and radiation scattering will start to transmute the interior of the chamber, in ways that the gamma rays radiated by normal antimatter annihilation would not cause.

I'm not so convinced that your scheme of bombarding a dense metal target with antiprotons is the best one.

At this point I'd want to refer to the literature...

But more generally, I just used the assumption that the warp core runs on deuterium/antideuterium because that way I could have the fuel used in fusion and antimatter reactors be commensurate. The core idea here is much simpler- that antimatter reactions are or can be so much more efficient than fusion reactions that the given "ten to one" matter to antimatter conversion ratio actually makes it worthwhile to synthesize antimatter rather than run raw hydrogen feedstock through a fusion plant for electrical power.

Given how much Trek loves to claim they've got science down pat, I wonder if they've somehow mastered quantum tunneling? The reason I ask is because to master quantum tunneling would reduce the raw energy requirements of fusion, similar to what happens in stars, and would make fusion much more efficient from an energy production standpoint. Given that they use Heisenberg Compensators for transporters, I could see the fusion reactors aboard a starship using this to combine Hydrogen 1 and Boron 11 to form 3 Helium 4's, which is the most promising for aneutronic fusion.

I'd run the math but this is theoretical stuff and I have no idea what the energy outputs would be.

Since we're explicitly told that the fuel for Trek ships is 'deuterium,' deuterium-deuterium fusion just seems to be what they're doing. Ideal things like aneutronic fusion might well be within the envelope of the possible for them, but if there's no support in the literature for them doing it, they're not doing it.

[shrugs]

[Baffalo]

Your osmium target will be hellaciously radioactive within short order, and radiation scattering will start to transmute the interior of the chamber, in ways that the gamma rays radiated by normal antimatter annihilation would not cause.

I'm not so convinced that your scheme of bombarding a dense metal target with antiprotons is the best one.

I was under the impression you got hellacious gamma bombardment regardless when you smacked proton on anti-proton. I could be wrong.

Since we're explicitly told that the fuel for Trek ships is 'deuterium,' deuterium-deuterium fusion just seems to be what they're doing. Ideal things like aneutronic fusion might well be within the envelope of the possible for them, but if there's no support in the literature for them doing it, they're not doing it.

[shrugs]

From what I understand reading about fusion on Wikipedia, the 80s were still kicking around the idea of cold fusion, with only a few actual experiments taking place, and those focused entirely on deuterium-deuterium fusion or deuterium-tritium fusion. They hadn't discovered the other types yet, especially as the first controlled fusion experiment didn't happen until 1991. So... they probably were going with what they had and they were so busy making up technobabble by the time the other shows rolled around that they never bothered updating the literature.

[Borgholio]

Well deuterium / deuterium and deuterium / tritium fusion reactions are among the easiest to initiate, and hydrogen is plentiful, why would they need anything else?

[Simon_Jester]

Your osmium target will be hellaciously radioactive within short order, and radiation scattering will start to transmute the interior of the chamber, in ways that the gamma rays radiated by normal antimatter annihilation would not cause.

I'm not so convinced that your scheme of bombarding a dense metal target with antiprotons is the best one.

I was under the impression you got hellacious gamma bombardment regardless when you smacked proton on anti-proton. I could be wrong.

You do. But hellacious gamma bombardment is not the problem.

The problem is that when you start randomly transmuting individual atoms, pretty soon you will have large amounts of various unstable isotopes kicking around and spamming alpha and beta particles and neutron radiation. These will in turn transmute random individual atoms in whatever they touch.

Random transmutation of atoms alters things. That's a problem if the exact chemical makeup of the material that's getting bombarded is an issue. Say, because it's a crystal made out of, oh, dilithium.

In real life this is an issue in nuclear reactors.

Hydrogen fusion and a gamma ray creating annihilation reaction are both relatively "clean" when it comes to this kind of secondary irradiation of the surrounding materials. Fission, or atomic nuclei shattering in any way, or having random nucleons punched out of a larger nucleus by antimatter annihilation events... not so clean.

Since we're explicitly told that the fuel for Trek ships is 'deuterium,' deuterium-deuterium fusion just seems to be what they're doing. Ideal things like aneutronic fusion might well be within the envelope of the possible for them, but if there's no support in the literature for them doing it, they're not doing it.

[shrugs]

From what I understand reading about fusion on Wikipedia, the 80s were still kicking around the idea of cold fusion, with only a few actual experiments taking place, and those focused entirely on deuterium-deuterium fusion or deuterium-tritium fusion. They hadn't discovered the other types yet, especially as the first controlled fusion experiment didn't happen until 1991. So... they probably were going with what they had and they were so busy making up technobabble by the time the other shows rolled around that they never bothered updating the literature.

Deuterium and tritium are still widely accepted as likely fusion fuels. I don't consider the idea "fusion reactors burn deuterium" to be dated.

[Baffalo]

DAMN IT!

Sorry, I had an idea on the drive home from work. Alright, so we know that the Enterprise or Voyager is pulling stray hydrogen through her ramscoops. The fusion process requires heating the hydrogen such that it naturally strips it of its electrons... wouldn't they do that anyway? If they pull the electrons as they take in hydrogen, it's safe to assume that it can be used for some electricity generation, which would be useful in producing power. I mean, waste not want not, right?

Even if it's a small amount of power, that would still contribute in some small way. Unless those bioneural gel packs and other junk have completely done away with electron-based circuitry by the 24th century.