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#3020 by frobnicat on 08 Nov, 2014 09:53
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...
Please, please Frobnicat, you are going too fast for me.
more energy to go from 100 to 101 than to go from 0 to 1. Because of the square.
100˛ to 101˛ -> needs to add 201
0˛ to 1˛ -> needs to add 1
Wow, again, seems paradoxical, as this is the same "thing", just seen from a different way...
- Nobody should add kinetic energy in different reference frames. That's not a paradox, that's plain and classical mechanics. A consequence is that nobody should use trust/power ratio.
This is not what is going on. What is going on is choosing a given arbitrary inertial frame, and working from there. I know there is no paradox. Anybody can use thrust/power ratio in a given arbitrary inertial frame and it will give correct results if the system is losing enough mass in the process. Thrust/power is ok because the power is from the onboard generator, and thrust has an effect of the variable of interest (velocity) that is linear.
Onboard generator -> given power OK (don't depend on frame)
given power -> given Thrust (from Ts) OK (don't depend on frame)
given Thrust -> given acceleration OK a = F / m ( don't depend on frame)
acceleration -> (Vf - Vi)/delta_t OK ( don't depend on frame)
For the last : Vf and Vi magnitudes do depend on frame, but the difference Vf-Vi dont.
So, this is not a problem with using Thrust/Power
The problem in Appendix A is that there is an error, a huge error, when calculating the Hall thruster in the frame of CMB : the change in kinetic energy is given by initial state minus final state. Which yields a value higher than the spent onboard energy. BUT but but, the change in kinetic energy should be the other way around, final state minus initial !!!
Which would yield a negative value, that is obviously less than spent energy. So their calculation is plain wrong, so is their conclusion that a Hall thruster is as much paradoxical as a Q thruster. The calculation done properly show quite the opposite : the Hall thruster has a perfectly sane energetic behaviour in whatever frame, even when using Thrust/Power as a mean to know its acceleration, and the same calculation for Q-thruster (not done in the paper) show it has a pathological behaviour in some frame, giving more kinetic energy than energy spent.
This is as simple as that, this is gross (playing on a sign convention) and subtle (relativity, even Newtonian, has interpretation subtleties, and nobody really like to check sign conventions). But in money terms maybe it's more clear : doing a financial operation where a cash investment of 1000$ (spent energy) makes that your portfolio values (kinetic energy) goes from 100000$ before to 10000$ after you would not say that the change in portfolio value is before-after 100000-10000=90000 and you had 90 over unit gain factor. You would do after-before and see that you have a change of -90000 and lost 90 times the cash invested : this is not really over unit gain. The difference probably fell into someone else pocket. Financial system is not exactly conservative but see the point : change is not initial-final, it's final-initial, this is gross, and turns the conclusion on it's head.Quote- There is no ongoing conspiracy at NASA, only usual business in an agency that consumes 2 billions each years and wants to survive. To survive it needs people support.
People enjoy Startrek stuff (I am not joking, I really mean it). So NASA (and Discovery TV, and a handful of SF authors and some NASA consultants) feed people with the stuff they ask. That's a profitable business.
Yeah, I do enjoy Startrek a lot too. But when you see people signing under NASA stamp EM simulations showing net asymmetry in momentum of photons bouncing inside cavity, while Greg Egan a "hard" science fiction author does a perfect job at showing how EM waves bouncing in an asymmetric cavity yields a perfectly symmetric result of 0 net thrust, then you see there is a problem. I would be tempted to give more credits to wild speculation of scifi authors than to scientists working on propellentless schemes. We'd better see how to fix the polarized negative power coupling axis on the Falcon Millenium...
I'd rather stick with working on more concrete hypothesis for explaining the apparent experimental results, but when I saw this Appendix A I couldn't keep silence : there is a huge error in this paper, and there is a completely wrong conclusion drawn from this huge error. This would need at least a public acknowledgement and proper correction from the authors if they are serious about doing science.QuoteIf one want serious science papers, there are many reputable sources. Science journals mostly, not conference papers, not pre-print servers, not self cited papers.
I know it may sound harsh, I don't want to be harsh, sorry for my lack of writing gift. This whole thread is going too far, intelligent people see artifacts and meaning where there is none. I am very sorry about that.
I am sorry that people working on those advanced concepts are doing such mistakes and bad methodology. There should be room for speculations and bold experiments. Appears there is no "serious science paper" dealing with energy conservation for propellentless schemes (is there ?). We would be very happy to see more than conference papers, pre-prints, self cited papers, on the subject. Appears the public production of people involved is kept at that level.
So what do we do ? Leave the subject altogether ? Don't tempt me.
If we want to keep on discussing propositions of the proponents then we are left with no options but to read and comment publications of that level.
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#3021 by Mulletron on 08 Nov, 2014 11:25
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To really get to the bottom of the issue of "paradoxical mission profiles" (if they are or not is not unanimous.... in Nasa's defense in both the Brady et al paper and the Human Outer Solar System Exploration via Q-Thruster Technology paper, they play it safe with 0.4 N/kWe) and similar questions concerning Q thrusters, I really need to understand the most fundamental part of the issue at hand. That is the behavior of Casimir momentum:
http://arxiv.org/pdf/1304.6767v2.pdf
Similar subject as what I've posted before, same authors. Different subject.
Break.
Did I mention that a conference paper isn't a venue for peer review? Neither is the Human Outer Solar System Exploration via Q-Thruster Technology paper. They can pretty much say whatever they want in those things. They are a tool for drumming up interest. That's about it.
We can get all excited about things if an actual legit paper ever gets released supporting Q thruster theory. Perhaps someone here can author one, given what we may have uncovered here on this forum. -
#3022 by frobnicat on 08 Nov, 2014 12:37
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To really get to the bottom of the issue of "paradoxical mission profiles" (if they are or not is not unanimous.... in Nasa's defense in both the Brady et al paper and the Human Outer Solar System Exploration via Q-Thruster Technology paper, they play it safe with 0.4 N/kWe) ...
I don't know if having more (properly accounted) kinetic energy than (properly accounted) spent energy is paradoxical but think there is near unanimity that this is not scientifically correct. This wide unanimous crowd is simply unanimously ignoring those research.
I can't let say that 0.4 N/kWe is "playing safe" : first a convincing reproducible experiment showing such stable level for a long duration (say, an hour) is still unreported that I know of, second and most importantly anything above .00000333 N/kW (photon rocket) is not safe as far as energy conservation is concerned.
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#3023 by Mulletron on 08 Nov, 2014 12:51
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To really get to the bottom of the issue of "paradoxical mission profiles" (if they are or not is not unanimous.... in Nasa's defense in both the Brady et al paper and the Human Outer Solar System Exploration via Q-Thruster Technology paper, they play it safe with 0.4 N/kWe) ...
I don't know if having more (properly accounted) kinetic energy than (properly accounted) spent energy is paradoxical but think there is near unanimity that this is not scientifically correct. This wide unanimous crowd is simply unanimously ignoring those research.
I can't let say that 0.4 N/kWe is "playing safe" : first a convincing reproducible experiment showing such stable level for a long duration (say, an hour) is still unreported that I know of, second and most importantly anything above .00000333 N/kW (photon rocket) is not safe as far as energy conservation is concerned.
Sep'n this ain't no photon rocket. It is more like a quantum sail IMHO.
See my colorful comments on page 195.....for why I think it works like a quantum sail. You have to apply power to this EMdrive (quantum sail) for it to work. The subject of all those papers I keep posting on here since page 126 deal with transferring momentum from the QV to matter.
It took me 69 pages for that to finally sink in. -
#3024 by JPLeRouzic on 08 Nov, 2014 13:11
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* I wrote about what you stated at 12:01 AM in the server time, it is still quoted above. Your last post (09:53 AM) is about a different issue.
......
Please, please Frobnicat, you are going too fast for me.
more energy to go from 100 to 101 than to go from 0 to 1. Because of the square.
100˛ to 101˛ -> needs to add 201
0˛ to 1˛ -> needs to add 1
Wow, again, seems paradoxical, as this is the same "thing", just seen from a different way...
- Nobody should add kinetic energy in different reference frames. That's not a paradox, that's plain and classical mechanics. A consequence is that nobody should use trust/power ratio.
The problem in Appendix A is that there is an error, a huge error, when calculating the Hall thruster in the frame of CMB : the change in kinetic energy is given by initial state minus final state. Which yields a value higher than the spent onboard energy. BUT but but, the change in kinetic energy should be the other way around, final state minus initial !!!
Which would yield a negative value, that is obviously less than spent energy. So their calculation is plain wrong, ...
...
* Unfortunately for me physics is not my professional domain, so I don't understand your reasoning (09:53 AM) of a craft that has a speed increasing and a decreasing kinetic energy. (Ef - Ei) < 0 => Ef < Ei.
* Anyway I still think the fact kinetic energy can't be added or substracted on different reference frames, applies to what you say in your last point (end-start vs start-end)...The rocket has different speeds at start and end points, so it's different inertial frames.
* If you feel they made a mistake, maybe the best is to write to the paper authors...
(edited because of typos) -
#3025 by Mulletron on 08 Nov, 2014 13:15
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@JPLeRouzic. Look at my comments on page 192 about the false paradox. It is as simple as this. A chemical rocket/ion thruster/whatever, that is gaining speed can still lose kinetic energy because it is losing mass by losing fuel. I showed it mathematically. I actually did some math around here.
There is no perfectly efficient thruster out there. -
#3026 by JohnFornaro on 08 Nov, 2014 14:27
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Now, granted, you'd need a serious power plant to power this thing, and you'd probably want to tie a few dozen of them together in a frame of some sort, but it should get you to near relativistic speeds for far less energy cost than a rocket.
Unless I'm missing something critical.
I think you are missing somethhing critical. They call it mass.
Note that solar sails are very big, and that solar satellites are very small and light.
All of your lazers and power plants are very massive. The device will hardly move. However, place your lazers on a handy airless planet, and aim them at a solar sail, and you can get the thing to move.
And Just review the cute video I posted a few pages ago. -
#3027 by JohnFornaro on 08 Nov, 2014 14:37
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But in money terms maybe it's more clear : doing a financial operation where a cash investment of 1000$ (spent energy) makes that your portfolio values (kinetic energy) goes from 100000$ before to 10000$ after you would not say that the change in portfolio value is before-after 100000-10000=90000 and you had 90 over unit gain factor. You would do after-before and see that you have a change of -90000 and lost 90 times the cash invested : this is not really over unit gain.
Obviously, you don't know how building contractors work. Let's say a contractor bids a house at $100,000, expecting to make a 20% profit, or $20,000. Suppose also that his costs were higher than estimated and he only makes a 15% profit, or $15,000. He tells his next customer that he lost $5,000 on the previous house, and that the next one will have to cost $105,000, to properly cover the cost of materials.
Happens all the time. -
#3028 by JohnFornaro on 08 Nov, 2014 14:42
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If you feel they made a mistake, maybe the best is to write to the paper authors...
That would be a waste of time. They will not engage the bonifide math whizzes on this thread. -
#3029 by frobnicat on 08 Nov, 2014 14:59
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...
* I wrote about what you stated at 12:01 AM in the server time, it is still quoted above. Your last post (09:53 AM) is about a different issue.
* Unfortunately for me physics is not my professional domain, so I don't understand your reasoning (09:53 AM) of a craft that has a speed increasing and a decreasing kinetic energy. (Ef - Ei) < 0 => Ef < Ei.
not sure I understand the time stamps issues ...
As Mulletron just said, and as my calculations show also in detail, this is about the action/reaction (classical, ion thruster or chemical) implies that the spacecraft mass is decreasing. So that in some frame it appears the kinetic energy decreases. For instance take a wandering big asteroid as an arbitrary inertial frame reference. Consider a 1 ton spacecraft that has a velocity 10km/s relative to it. Would it be to smash into it, the impact would release .5*1000*10000^2 = 50 billion Joules. Now consider the same spacecraft after it has used half its mass in propellent (chemical burn, relatively low Isp) to get 2km/s delta V. Velocity relative to asteroid is now 12km/s. The 500kg dry mass (mission payload) has obviously gained kinetic energy (relative to asteroid). But if it were to smash now, it would release only .5*500*12000^2 = 36 billion Joules. Less kinetic energy because the first crash implied a lower velocity but a much higher mass. There is no paradox. There is no playing between different frames of reference, there is only one frame in this example, that of the asteroid. A frame of reference is the frame in which you measure the velocities. This is not a matter of having different velocities, many velocities measured relative to the same inertial body is still one and only one reference frame.Quote* Anyway I still think the fact kinetic energy can't be added or substracted on different reference frames, applies to what you say in your last point (end-start vs start-end)...The rocket has different speeds at start and end points, so it's different inertial frames.
Don't want to be rude but : no.
As example above shows, different speeds is not different frames. The different speeds are measure relative to one and only one inertial body. I'm not trying to confuse or mystify you, ask any scientist/engineer/teacher who knows to handle Newtonian mechanics routinely, there is consensus, this is perfectly understood and leaves place to no ambiguity. Take "smashing into the big inertial body of reference" as the "proof of concepts" that would make things real and not just a play of words and numbers, that is (could be) very real. The impact would make less bang for 500kg at 12km/s than 1000kg at 10km/s.Quote* If you feel they made a mistake, maybe the best is to write to the paper authors...
Yes maybe, I'm considering that. Thing is, I'm just an anonymous poster, part time amateur scientist interested in the subject but with no credit in the domain. They should know better, their peers should know better. I'm the last person that should signal that to them.
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#3030 by Mulletron on 08 Nov, 2014 15:13
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@Frobnicat et al.
Please excuse my excursion to the Oracle, but her answers on this subject will make things as right as rain:
http://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration
"It gets harder to push a ship faster as it gets closer to the speed of light
This is a half-myth because it depends on the frame of reference. It is true for those watching from the planetary reference frame. For those experiencing the journey (in the ship's reference frame) it is not true. For both the planetary frame and the ship's reference frame, the ship will change speed in a Newtonian way—push it a little and it speeds up a little, push it a lot and it speeds up a lot. However, in the planetary frame the ship will appear to be gaining mass due to its high kinetic energy, and the Mass-energy equivalence principle. Should the engines be giving a constant thrust, this will result in progressively smaller acceleration due to the higher mass it is required to accelerate.
From the ship's frame, the acceleration would continue at the same rate. However, due to Lorentz contraction, the galaxy around the ship would appear to become squashed in the direction of travel, and a destination many light years away would appear to become much closer. Traveling to this destination at sub-luminal speeds would become practical for the onboard travellers. Ultimately, from the ship's frame, it would be possible to reach anywhere in the visible universe, before the ship has time to accelerate to light speed."
In the end, we're not going to violate any conservation laws. We're limited by the finite amount of energy we can carry within any spacecraft. We're also limited by SR.
Appendix A in that paper failed mathematically, scientifically by adding together reference frames, and by using a false analogy with Hall thrusters. Every way you look at it, it is just plain wrong.
The further concerns brought up here in this forum apply to photon rockets, which we aren't dealing with here. EMdrive isn't a photon rocket.
The final concern about QV derived thrust is still a valid concern. I of all people acknowledge this. And I am championing the QV approach.
As long as nobody calculates a specific impulse of infinity, we're safe. -
#3031 by Ron Stahl on 08 Nov, 2014 18:44
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It doesn't make sense to me to read that Woodward's electron model is"easy to test", and then read that "if the model is correct", that all HSF would be transformed and enabled, and physics would change, and all that.
I agree--it doesn't make sense. Woodward's work gives validation, but what one needs is replication. Since there is no money out there for this, we have the situation we have. The ZPFers are handling all the money, such as from DARPA. That's what I'd like to change if I can find a PI for a grant.
Shouldn't all this "easy"testing be done first? And then all that transformation? -
#3032 by Ron Stahl on 08 Nov, 2014 18:51
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So in the end this is just "free energy in disguise". Think it's not good to have things in disguise in science, this is not sane. I'm ready to hear that those thrusters emit tachyons (negative energy). I'm ready to hear that quantum vacuum is like criss-crossing asphalt roads at all velocities and you can choose to push on the ones that are slow relative to you, taking at low energy cost (possibly 0) the intrinsic energy from those conveyor belts. That would be crazy but that would be all right : any idea without hidden secrets or "mysteries" or mystifications has a right to be expressed in science. . .
Well you've hit on another of my pet peeves. Neither QVM nor ZPF has an explanation that preserves conservation. This is why it is specifically called a conservation violation in the Eagleworks literature. Woodward has taken the opposite tack--he claims that since such a high thrust efficiency device needs to generate temporary negative mass, conservation is preserved. First of all, the energy and momentum is accounted for by the enhanced entropy of the entire system--the universe--and secondly that mass has negative inertia, so when you sum the local system, you don't get the obvious violation. This is at least an attempt to balance the books and something the QV folks can't do. -
#3033 by Ron Stahl on 08 Nov, 2014 19:00
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According to Woodward, this entire method is flawed and the correct way to do the cal is to "sum the instantaneous frames of rest" which is to say, use the tools of GR. He handled this objection in some detail a couple years ago and since that time, one of the guys over at T-P managed to do the same calc without the GR tools and get the same answer, but this is not to say one ought expect to use the wrong tools and get the right answers. This kind of calc needs to use GR since the frame the thruster is in is accelerating and is non-inertial. And yes, you are completely correct that the trouble comes when you " add up kinetic energy in different reference frames" however, GR does include the tools to do this properly. This requires a transform that is well beyond my training.something really outrageous is going on in this Appendix. Second column. Read it well, read it again, check the maths.... this is both gross and subtle.
You mean what people call the "kinetic energy paradox"? That kinetic energy is proportional to the square of speed?
https://www.physicsforums.com/threads/kinetic-energy-and-frames-of-reference.534883/
It is what you already mention as a paradox as well as GoatGuy and it is also used in this linked paper.
What physicists say, is that one can't add up kinetic energy in different reference frames (nothing to do with relativity).
In my opinion every people using a metric like trust/power for several segments of the same travel, are doing exactly this mistake...adding kinetic energy in different reference frames -
#3034 by Ron Stahl on 08 Nov, 2014 19:08
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There we are : this is not a paradox or a problem with propellentless schemes, this is a paradox inherent to any spacecraft when energy is accounted for in an inertial frame fast enough relative to those typical delta Vs, because any of those has a Ts such that 1/Ts < high speeds, so surely any spacecraft can (apparently) provide more energy in kinetic form than is spent by the onboard generator. This is not a paradox with Q-thrusters, this is a paradox with relativity of velocities and how kinetic energy is accounted for in different inertial frame (we all know this is a messy business with all this square thing and non additivity...)
So far as I'm aware, this above is completely correct. On his reading list, Woodward demonstrated this seeming violation occurs with any sort of thruster on a swing arm. And as I said, his solution was to "sum the instantaneous frames of rest" which is some sort of transform used in GR. It was in fact his demonstration that this seeming violation occurs with any thruster that sold me we need a difference in kind to get this kind of performance, and the difference is of course that mass with negative inertia makes an unusual contribution, and can account for the trouble.
See Forward's analysis here: http://en.wikipedia.org/wiki/Negative_mass -
#3035 by 93143 on 08 Nov, 2014 20:09
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On his reading list, Woodward demonstrated this seeming violation occurs with any sort of thruster on a swing arm.
And I demonstrated here that that only happens when you fail to properly account for the energy of the propellant - ie: you draw the box too small and fail to close the system.one of the guys over at T-P managed to do the same calc without the GR tools and get the same answer, but this is not to say one ought expect to use the wrong tools and get the right answers.
You do not need GR to get the right answer in this case. I'm not sure what exactly Woodward was doing, but either he was wrong or you misunderstood him. (From your description, I suspect the latter.) The energies and velocities are low, the distances involved are small, and space can be assumed to be approximately flat. Really it's no more than a first-year mechanics problem, as I clearly showed at the above link.
You've seen my qualifications, so you should know I live and breathe Newtonian mechanics, and I can easily tell when a model problem is outside its domain. This one isn't.
Furthermore, if you attempt to use GR to get conservation without accounting for the energy of the propellant as I do above, you will fail in the general case, and for exactly the same reason: because what you have is an open system. It isn't a matter of my method being 'alternate'; it's a matter of my method being right. Doing the problem in GR would be more complicated, and would account for cosmically large, arbitrarily dense components and relativistic velocities, but without accounting for the energy of the propellant it would still end up wrong.
That's why I don't like the "recycled propellant" description of a Mach-effect thruster. It draws the box too small, and you still ultimately get a conservation violation. You need the interaction with the "far-off active mass" to make the idea work. -
#3036 by frobnicat on 08 Nov, 2014 20:33
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There we are : this is not a paradox or a problem with propellentless schemes, this is a paradox inherent to any spacecraft when energy is accounted for in an inertial frame fast enough relative to those typical delta Vs, because any of those has a Ts such that 1/Ts < high speeds, so surely any spacecraft can (apparently) provide more energy in kinetic form than is spent by the onboard generator. This is not a paradox with Q-thrusters, this is a paradox with relativity of velocities and how kinetic energy is accounted for in different inertial frame (we all know this is a messy business with all this square thing and non additivity...)
So far as I'm aware, this above is completely correct. On his reading list, Woodward demonstrated this seeming violation occurs with any sort of thruster on a swing arm. And as I said, his solution was to "sum the instantaneous frames of rest" which is some sort of transform used in GR. It was in fact his demonstration that this seeming violation occurs with any thruster that sold me we need a difference in kind to get this kind of performance, and the difference is of course that mass with negative inertia makes an unusual contribution, and can account for the trouble.
See Forward's analysis here: http://en.wikipedia.org/wiki/Negative_mass
By reading again my irritated post you are quoting an extract from I realise it might be not clear ( to people giving credits to maverick science thinking ) when I speak for what I understand the authors are saying and when I speak for what a "classical scientist" ( let's say this is my case ) would say, sorry for that.
The bold statement above you are quoting was ironic. This is what I understand the authors are implying and I think it is completely bogus.
It doesn't take GR and erudite summations in "the instantaneous frames of rest" to understand that there is no seeming violation of conservation from whatever known proven thrusting device (be it a car on road, a chemical rocket, a ion driven probe, a photon rocket) whatever is the one arbitrary inertial frame of reference used to measure speed and account kinetic energy for, be it in Newtonian mechanics for small speeds, or at any speeds for special relativity. Million people that are studying and designing the cars, rockets, washing machines, guns, planes and all other devices that work on Newtonian mechanics can tell that : there is nothing paradoxical, not even a hint at, not anything a little mysterious like renormalization techniques in QFT, not anything that would make interpretation hard or ambiguous.
GR is for dancing around singularities or ultra-precise trajectories measurements. It isn't required to show that a .4N/kW ion thruster in deep space does not violate or seem to violate anything by 20 times. Well understood Newtonian mechanics is enough for that. While a propellantless thruster does clearly seem to violate energy conservation by 20 times or by 2000000000 times depending on the arbitrary inertial reference frame. Now if you say that a propellantless thruster needs GR to be shown conservative, in a more complex way, precisely because it shows such ill defined behaviour in Newtonian mechanics and SR, I'm listening
The only "classical case" I'm aware where such a well known proven device would show such seeming violation relative to inertial frame in SR is when the relative speed to rest frame is above c. That is we have an already above c spacecraft, thrusting even more on classical particle ejection. Reciprocally a spacecraft below c thrusting on tachyons (above c particles) would show such apparent violation (but no violation when taking properly into account the emitted negative energy).
I'm ready to hear about that, not gibberish about seeming violations of classical mechanics because classical mechanics show no such appearance of violation when dealing with classical devices, and this is just mystification to say that they do.
If you or anyone think to have seen a "seeming violation" in Newtonian mechanics or SR, then please put the case in clear terms (what is violating what relative to what) and it will be my pleasure to either show that there is an error in the calculation, or that there is no violation, real nor apparent. If someone is trying to sell you a seeming appearance of violation from a classical device (ion thruster, washing machine...) then, I tell you, a million people doing rockets and planes tell you : consider that he is trying to mystify you (maybe he is himself mystified, or self-mystified).
oops, I see 93143 answered faster. Glad to hear someone of the million people...
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#3037 by Mulletron on 08 Nov, 2014 20:52
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#3038 by Mulletron on 08 Nov, 2014 21:22
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You know......All of this is starting to come full circle. All this talk about magnetochiral this, and diamagnetic QED vacuum blahbidibla that, angular momentum, spin, helicity talk (magnetism is due to electron spin, simply put) is supporting why the TE mode seriously outperformed the TM modes according to the Brady et al paper. This is all boiling down to QV-magnetic interaction in the presence of PT symmetry breaking.
My mixologist keeps explaining this to me but her timing is horrible and I keep forgetting!
There is something going on here!
Disclaimer, that 1880.4mhz freq is also below the cutoff for 6.25 inches, which is why I went crazy on evanescent field coupling for a couple weeks.
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#3039 by Rodal on 08 Nov, 2014 21:46
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http://ptp.oxfordjournals.org/content/119/3/351.full.pdf+html
As I have pointed out previously, this requires anisotropy, and the author makes it clear (even in the title). "Momentum Transfer between Quantum Vacuum and Anisotropic Medium"
Peculiar indeed.
The author further points out:QuoteIn most conventional electromagnetic media, the quantum vacuum inside possesses a universal symmetry and hence has no influence on the motion of the media. However, for a Faraday chiral material,the macroscopically observable mechanical effect, due to the breaking of the universal symmetry of the quantum vacuum may appear
What the author is discussing does not apply to the EM drives researched by NASA Eagleworks because the materials used are isotropic. (Copper in all cases and in some cases Teflon or Polyethylene dielectrics -injection molded-)