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2015-05-21, 05:42 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Partly. They figured out that with investing into uranium research, they could get nuclear energy and nuclear weapons at the same time. If you develop thorium reactors, you still need to do all the uranium research anyway for weapon development. It was just economically cheaper to focus completely on uranium and shelf thorium.
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2015-05-21, 05:58 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
On the 'fusion fuel isn't radioactive' point - note that tritium is, and even a reactor which is designed to run primarily on deuterium will likely use some tritium to make the initial ignition temperature lower. If the reactor cycles fuel pellets as some proposed designs do then it'll use some tritium every time.
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2015-05-21, 06:46 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
I do know the LM pocket reactor will use Tritium, but it will also produce the majority it needs.
Hiw radioactive is the stuff?
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2015-05-21, 06:54 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Lockheed were talking about first generation reactors producing some radioactive waste, but not as bad as current-gen fission reactors, mainly because of used parts from what I remember.
Anyway, it's not like radioactive waste is anywhere near the same kind of problem global warming and air pollution are. It's sad to say but the biggest impact of Chernobyl and Fukushima (which as I understand is close to 0 for Fukushima) wasn't the people who actually died directly because of them but the hundreds of thousands of people who have and will die from lung cancer because of coal plants that weren't replaced and the victims of famine global warming will create in the next few decades.
Finally, about Lockheed's credibility. I don't know nearly enough about the tech to make a judgement call on it, but I do know a bit about business and strategy. It seemed to me like the video and press coverage had 2 objectives. First they're at the point where they need more people and were trying to reach grad students and experts who might want to work on the project. Second, Lockheed is in the military hardware business, not the civilian energy business. No reason for them to try and commercialize their reactors when/if they are ready alone if they can create a joint venture with for example GE, spread out the R&D investment (which is probably about to ramp up considerably) and have access to their contacts and know-how when the time comes.
That doesn't seem to me like the move of a company that's pushing a long shot and agitating for media chatter, more like a company that has a promising product and is at the point where they need more resources to finish it.
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2015-05-21, 06:59 AM (ISO 8601)
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- Feb 2008
Re: The "Now" implication of Fusion Power
Tritium has a
6 day(12 year, I misremembered) half life IIRC so it'sreallyquite radioactive. There's no way it can be mined (& storage losses are significant) so it has to be made specifically for the purpose it'll be used for.
At a guess Lockheed's reactor is designed to include a heavy water blanket; some of the stray neutrons emitted will be absorbed by a deuterium nucleus & will convert it to tritium. A leak of stored tritium or of partially converted heavy water could pose a danger beyond the immediate area, but not a long lasting one(6 day half life, remember.)- well, not as much as an accident with a fission reactor. For that you'd need some sort of accident which sends bits of irradiated metal everywhere.Last edited by avr; 2015-05-21 at 07:13 AM.
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2015-05-21, 08:11 AM (ISO 8601)
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- Aug 2007
Re: The "Now" implication of Fusion Power
What does tritium decompose into, and how many steps before it reaches a non-radiactive atom? I know that one of the problems with the leftover radioactive crap of fission is the fact that it will go through like 6 different radioactive elements before finally decomposing into stable lead, some with very long half-lives (containment issue) and some with very short ones (health issue)
Also, while 12 years is bad, the amounts matter. To hear LM tell, it will require tiny amounts of tritium ("There is a very minimal amount of radioactive tritium—it’s on the order of grams"), so if we are talking 1 kg of irradiated tritium per generator per year, how bad would it be?
Thanks,
Grey WolfLast edited by Grey_Wolf_c; 2015-05-21 at 08:35 AM.
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2015-05-21, 08:23 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
No, they're a lot worse.
Fusion power is not clean power. Fusion may not create the radioactive waste that fission does but it produces a lot more radiation. Even if you could make a internal combustion engine sized fusion reactor, it would need so much shielding that you couldn't make a fusion powered car with it.
I wouldn't want a fusion reactor any where near me."that nighted, penguin-fringed abyss" - At The Mountains of Madness, H.P. Lovecraft
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2015-05-21, 08:23 AM (ISO 8601)
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2015-05-21, 09:09 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
This is true, but people forget that it is possible to make a much smaller bang with a fusion bomb than with a fission bomb as well. Look at the 50 pound W54 warhead used in the Davy Crockett recoilless rifle, for example. The W54 has an adjustable yield from 10 tons to 1 kiloton TNT equivalent, made possible by its fusion design.
Also, the W54 was developed in 1961, so it didn't take terribly long to go from earth shattering megaton kabooms to tiny(for nuclear devices,) highly efficient warheads. This is only 9 years after the Ivy Mike test of an impractical liquid cryogenic fueled fusion device of approximately 10.4 megatons yield.
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2015-05-21, 09:55 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Tritium decays via beta decay, which means it emits a proton, an electron and an antineutrino all at once and turns into deuterium. The electron isn't as high energy as many radioactive decay products can be, and the main danger is if you drink tritiated water and it decays inside you. Deuterium doesn't decay further, nor do protons or electrons.
Deuterium is poisonous in sufficient quantity (it messes up proteins it's incorporated into) but you'd have to really work at it to kill yourself that way, it's not something that could happen by accident.
A gram of tritium is actually a hell of a lot of radioactive material if it's in one place. On the order of a million curies if I haven't dropped a decimal place in my mental arithmetic. As water dropped into a river or the sea it would get diluted really really quickly though. That it was possible to detect a leak from Fukushima on the Californian coast is a tribute to the power of detection techniques, not an actual danger.
The neutrons and deuterons emitted by a working fusion reactor are a larger potential problem; you can't make the reactor out of elements which absorb these nicely* given the high power magnets and high temperature structural elements required (fission reactors are a little more forgiving that way). So the structure becomes radioactive over time. Also, the structure becomes brittle over time as atoms get displaced or changed by radiation and it will need to be replaced eventually.
* = edit: well, maybe if you work with incredibly pure, hence incredibly expensive materials. Not practical for something that needs to be economically workable.Last edited by avr; 2015-05-21 at 10:04 AM.
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2015-05-21, 12:36 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
D-T fusion produces far more neutrons per joule outputed than fission, and they are very fast. This means that if you build a reactor out of any old scraps you have there is a very good chance that it will get transmuted into something radioactive, possibly problematically so. This does not mean that you cannot build a reactor that remains non radioactive, simply that you have to be very careful of the elements that you use to build it. Even if tokamok fusion does not prove to be the way forward, the work ITER and similar experiments have done is valuable research on reactor construction materials for any D-T design. On the plus side those same fast neutrons can transmute some problematic elements into less problematic ones.
Generally tritium is produced by bombarding lithium with neutrons. Originally it was thought that only lithium 6 was good for this, but then castle bravo happened and they discovered that lithium 7 works just as well if not better, which is how they got the yield so wrong. Hydrogen bombs typically produce their tritium from lithium as they detonate, which is how they avoid the half life problem.
I think the davy crockett was a standard boosted fission device. Fission devices typically have an air gap as part of the design, and there is no good reason not to fill that with fusion fuel. The yield can be adjusted by changing the amount of fusion fuel in this gap. Worth noting is that in this design the fusion reactions do not provide a significant boost to the energy, instead rapidly increasing the neutron population which makes much more fission occur. At the 10ton yield the weapon was acting as a pure fission bomb, with no boost at all. It's relation to fusion tech is that in a thermonuclear bomb you need a fission bomb to start the fusion, and there is no point making this first stage larger than it has to be. This pushed research towards looking for the smallest bomb possible. The 'tiny' yield is because it only just goes super critical, rather than any fusion occuring.
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2015-05-21, 04:47 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Tbh they're acting like any other high-tech company that needs some more investor money. Make as many claims as possible about the use of it and then say "we're close to making that tech!". They never tell you how close they actually are. And since fusion is one of the hardest engineering challenges we are trying to beat, it's not unreasonable to assume they're not much further than anyone else. They just have better PR department.
And how exactly are we going to get "cheap" fusion? You know that uranium for reactors is quite cheap already? It's the reactor and building around it what's so expensive. I don't get why is everyone assuming fusion plants will be cheaper - you might not be needing so many safety measures, but because of more intense neutron bombardement you'll either will replace parts in the reactor often or it will have short (relatively to fission) working life. And all those superconductors cooled with helium are crazy expensive . . . You just can't overlook context. It's similar to dreaming about renewable energy - sunlight and wind are free, right? So making electricity from it will be also cheap!
Wrong.
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2015-05-21, 09:35 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
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2015-05-21, 09:53 PM (ISO 8601)
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2015-05-21, 10:25 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
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2015-05-22, 12:50 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Castle Bravo was far more powerful than expected, conducted under questionable wind conditions, and despite those factors it was still far cleaner than if you had produced the same yield with fission warheads. Bravo filled most of a building, but I'm pretty sure it would have been a football stadium full of fission warheads.
Bravo had a uranium tamper and fissionable material in the primary which contributed to the blast, but the radioactive tritium and lithium isotopes and such, while nasty, aren't the same as spraying uranium and plutonium around everywhere. A lot of the material making up the island was injected into the atmosphere and fell on the surroundings after being made radioactive.
Tsar Bomba was much cleaner because it was an airburst high enough that the fireball just barely got reflected off the ground, and because it wasn't spraying massive amounts of heavy radioactive elements everywhere.
A fusion reactor can turn the casing and such radioactive and that can pose problems but these can be dealt with, it isn't the same as carrying around a lump of plutonium or such.Engraved here is a rendition of an image of the Dwarf Fortress learning curve. All craftsdwarfship is of the highest quality. It depicts an obsidian overhang which menaces with spikes of obsidian and tears. Carved on the overhang is an image of Toady One and the players. The players are curled up in a fetal position. Toady One is laughing. The players are burning.
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2015-05-22, 04:17 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
"that nighted, penguin-fringed abyss" - At The Mountains of Madness, H.P. Lovecraft
When a man decides another's future behind his back, it is a conspiracy. When a god does it, it's destiny.
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2015-05-22, 05:40 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Yeah if we manage to make it much more effective then it's potential output will be higher than fission . . . but that will also make radiation conditions worse, bringing need for more shielding, making construction and maintenance more expensive. I still don't see why it's so often assumed fusion will be cheaper.
That doesn't apply for aneutronic experiments, but nobody seems close to making them work.Last edited by Tev; 2015-05-22 at 05:41 AM.
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2015-05-22, 09:14 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
How practical would it be to pop down a few dirty but powerful fusion reactors somewhere nobody cares about like the Moon, and then ferry some of the power they produce back to Earth using the rest of the power they produce?
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2015-05-22, 10:14 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Transmitting power over a distance like that would have its own problems. For instance, the most likely form the power would take is in the form of microwaves beamed down to the planet. Some of those will be absorbed by the atmosphere above the receiving station and cause problems in that way, and if the beam is not perfectly aligned you'll fry everyone who lives nearby. Plus there's the whole problem of getting all that heavy power generation stuff up into space in the first place, and also maintaining it.
The biggest issue with that whole idea, though, is why go to all that trouble to put fusion reactors in space when we have the biggest fusion reactor for light-years in any direction already pumping out power up there? Just intercept the energy coming from the Sun and beam it back to Earth in usable form and be done with it.
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2015-05-22, 10:24 AM (ISO 8601)
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- Aug 2007
Re: The "Now" implication of Fusion Power
IIRC, the "Microwave" power stations in Sim City 2000 where this technology - put a bunch of solar panels in geostationary orbit (where the atmosphere is not in the way, making them far more efficient) or even in a polar orbit high enough they are seldom in Earth's Shadow and then beam the resulting energy down to your city. Occasionally, the beam would miss and leave a hot trail of death by burning. Fun times. As I understand it, the concept is sound (the atmosphere and nighttime are the two biggest obstacles to solar power), but maintenance would be painful.
Once we have built a space elevator, though, a lot of these concepts will be a lot more plausible. Of course, a real space elevator is even further into the future than commercial fusion power.
BTW, I'm still a tad confused about the whole radiation angle. Is the main concern that the truck-sized casing would become radioactive, or the water in the boiler attached to it used to generate the actual energy? Or both? And how do nuclear ships and submarines deal with the problem these days (I'm assuming that if fusion has the problem, fission has it too - is that not the case?).
Thanks,
Grey WolfLast edited by Grey_Wolf_c; 2015-05-22 at 10:24 AM.
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2015-05-22, 10:42 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Well, the gist as I understant it is that the residue of Fission reactors decay by alpha decay (emitting a completely ionized Hellium atom) while the byproduct of Fusion reactors would decay by beta decay (emiting an electro and an electron antineutrino, or on beta+ decays, the positive charge equivalent). Due to it's size, alpha decays interact more with the enviorment, and thus have low penetrating power, while beta decays can go much further and even pass through the physical barriers, something that alpha decays are incapable (or at least very, very unlikely) to do.
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2015-05-22, 11:01 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
At this point we probably need someone who made real research on tokamaks and / or military HEU reactors (or at least read a few studies about them), because comparing real numbers and how hard is shielding, etc. in practice will make these questions answerable. Otherwise we will have to just wait and see how ITER plays out (or whichever finally-working alternative path) and what will be final parameters of using optimised fusion.
edit: I'm still betting that someone somewhere will decide to strip down classic fission reactors of overdone safety crap OR ignore weapons treaties and start using HEU reactors en masse for civilian use and we will see how cheap can fission actually be.Last edited by Tev; 2015-05-22 at 11:04 AM.
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2015-05-22, 12:54 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
The U.S. Navy uses pressurized water reactors(PWR) rather than boiling water reactors(BWR.) In a PWR, the amount of metal exposed to radiation is vastly less, since the reactor water is in a closed cycle between just the reactor and the heat exchanger. In a BWR, by contrast, the entire steam turbine assembly is exposed to radioactive water.
The reason we use BWRs at all is that they are much cheaper to set up initially, making it easier to get loans for the initial capital investment. PWRs are significantly cheaper to maintain in the long term, because their turbines are essentially just as safe to work on as the turbines in any steam power plant.
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2015-05-22, 01:20 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Well you just have to ask xkcd about how hard shielding is to discover that actually shielding is really easy on earth. You only have a problem if what is supposed to be inside the shielding escapes. Fission is difficult to manage the radioactivity of because it produces two daughter isotopes with far too many neutrons between them, and so are probably unstable. They can be a huge range of different isotopes with varying chemical and nuclear properties and there is very little you can do to influence which are produced. They are not nearly as heavy as the parent nucleus, but they are not light, making isotope seperation difficult after chemical seperation. Many of the products are very good at stopping your reactor working well, meaning that your fuel burnup rate is very low without reprocessing, which in turn means that you produce a lot of medium level waste rather than a little high level waste. This is before you consider the range of transuranics that can be produced when a fission event does not occur.
These complications are inherent to fission, and cannot be avoided. With fusion the problem is neutron activation of the reactor. The reactor can be made of whatever we like, so we can influence how this occurs. For example, if we build it entirely out of carbon, oxygen, hydrogen and silicon, which could be possible, then the same atom has to capture two neutrons before any radioactivity occurs, and even when this does happen we only have to deal with a small range of radioisotopes. If an element is problematic under neutron bombardment we can just avoid it, so there are no inherent problems (though that won't stop us making some).
HEU reactors are used by the military because they can be made much smaller than a conventional reactor, with the down side being that you have to enrich the uranium to a much higher degree. This makes them far more expensive to run.
The safety thing is a bit overblown but actually not that much of a problem for fission. Public squemishness is a stumbling block, but the lack of a good solution to the waste is the real biggy. Personally I think we should fuse it all into silica and then put it in a big pile on top of a deep salt lake. Let it get hot, and melt it's way down, then install water pipes to use it as for geothermal power to offset the cost of fusing it into silica. It might take a few hundred years, but we should be able to recover all the cost of disposal that way. It should be pretty safe too, with the salt melting and convecting if it overheats, and there being no water for miles. That might just be the mad scientist in me though.
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2015-05-25, 07:10 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
They are not " any other tech-like company". Its Lockheed Martin skunkwork. Their resume of doing what was thought impossible is.. Respectable, to say the least.
And you do realize that even if they do want to do this to find new partners to share the investment book, they will have to share the degree of their progress beforehand? Investing millions of dollars into a venture like that is not exactly like buying a used car. You get your own experts to study and assess the feasability of the project.
Which means LM feels confident enough in that project.
Its all a varying degree of "cheap", obviously.
Cheap in that case is a theoretical 5-meter generator that is technically mobile. It can be assembled in a dedicated factory and shipped where it needs to go. As the manufactoring progress can be chained like an automobile, manufacturing cost will be WAAY down compared to a current nuclear power plant, which requires years to build and each are technically fairly unique.
I just read that a fission power plant's operational costs is consisted of its initial capital outlay at a degree of 74%. That's a massive investment for any government or corporation. Plus, once its built, you are stuck with it.
A (technically) mobile Fusion plant.. Could be rented. You dont want it anymore? The Lockheed Martin truck will come pick it up. Sure, its not as simple as picking up a simple car, but its degrees of magnitude simpler than disposing of a fission power plant.
Material costs of a truck-sized plant are risible. The most costly aspect of it all will be Lockheed Martin's royalties every time you build a baby like that. But with time, the cost will diminish.
I dont think the Energy lobby will do anything to refrain from its use; as they will be stuck in a prisonner's dilemma. First one to start effectively use the Fusion reactors will put the others out of business. Thats capitalism for you. This is too big of a competitive advantage not to leverage. If you can afford to sell your energy at a permanent 10% discount, why not do it? Your additional sales will more than makeup for the diminished margin.
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2015-05-25, 08:36 AM (ISO 8601)
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Re: The "Now" implication of Fusion Power
That's the thing about this that people can't really grasp I think. This is the SKUNK WORKS. The place that created the SR-71, U-2, F-117, Flying Wings (B-1 Bomber). And they far more than plane designers. In order to build the aircraft they need to be experts in a lot of fields including materials technology and physics. You hit it right on the head. They are not "any other tech-like company".
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2015-05-25, 12:44 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
That was the skunk works, but worth noting is that the first 3 designs (and many more impressive ones) were all designed by Kelly Johnson. The forth is not a lockheed aircraft (I assume you mean the B2), and flying wings were almost used in the second world war in the Ho229.
If you had told me that Kelly Johnson thought he could make fusion work then yeah, I would take it seriously, but he has been dead for 25 years. Since then I have not seen anything from them that was not a natural progression of what they had done before.
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2015-05-25, 03:42 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Yeah, meant B2. And it was Jack Northrop who designed the XB-35, not Johnson which flew in 1946. But Johnson for all his brilliance, was one man. He needed the support of a great many people to do what he did.
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2015-05-25, 04:00 PM (ISO 8601)
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Re: The "Now" implication of Fusion Power
Something I just realized: Is this company (or department thereof) the origin of the name of the Skunkworks base facility in Sid Meier's Alpha Centauri?
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