em drive

[djolds1]

It is part of the Standard Model that virtual particles pop into and out of the quantum vacuum all the time. According to Sonny, this is where the mass comes from and where it goes. The real trouble is that these are VIRTUAL, not real particles. There are so many of them, that if they gravitated, they would cause the universe to collapse from its own gravity. Obviously, they don't gravitate, which is what makes them "virtual". However, Einstein's Equivalence Principle says that gravitational mass and inertial mass are not only indistinguishable, they are the same thing. So if virtual particles can't gravitate, they can't transfer momentum either. If they can't transfer momentum, then they can't be used for propellantless thrust. Hence our trouble. Sonny's "theory" which certainly does not rise to the level of a scientific theory, makes no sense at all as it is a denial of EEP. This is why Sean Carroll at CalTech calls it "bullshit".

Invoking Dr. White's "Quantum Vacuum" ideas is certainly unjustified as yet (and an easy way to confuse the issue), but Paul's exploration of M-E Effects and electrostrictive impacts from chamber metals on Jim's distribution list yesterday was MOST interesting. The fourth power scaling of M-E mathematics is killer, and the math for thrusts is within the order of magnitude for the reported performances of the various species of em-drive.

Perhaps we now see an inspiration or two to significantly boost MET performance?

[AcesHigh]

not all of us have access to Jim's email list. Could you please summarize what Paul wrote?

[djolds1]

not all of us have access to Jim's email list. Could you please summarize what Paul wrote?

X: “What puzzles me is the fact that with no dielectric, the tapered cavity produced no thrust, whereas it should have (according to Shawyer & the Chinese).”

That had us puzzled as well until Jim W. mentioned to me when asked that all metals are weakly electrostrictive. So at sufficiently high RF power levels multiplied by the resonant cavity’s Q-factor, which yields the peak E-fields obtainable on the surface of the resonant cavity’s walls with a given input power, similar force rectification process could be generate especially since the M-E and the Q-Thruster models predict force output scaling proportional to the E-field strength to the fourth power (V^4). Talk about non-linear responses!

Now what happens at ~20W with a Q-factor of 55,000 could be very different with a power level of 300W and a Q-factor of 55,000. In fact if you take the power-Q-factor product of these two examples, we get an M-E force multiplication factor for the 20W case of 1,100,000^4 = 1.464x10^24 verses 16,500,000^4 = 7.412x10^28 for the 300W case. That is a factor of 7.412x10^28 / 1.464x10^24 = 50,628X the force for the same cavity metal wall structure.

So if your force was say 2.0 micro-Newton at 20W with no dielectric, which is below our single-shot force detection range in the Eagleworks torque pendulum, especially on a noisy day, would indicate that the we might see around ~101,256 uN (101.256 milli-Newton (mN) running at 300W. If we now through in the fact that our TE012 resonant frequency was at 2,167 MHz instead of 2,450 MHz that Shawyer and the Chinese used, and assume a scaling factor of w^3 for this problem, we get a frequency boost factor of (2450 / 2167)^4 = 1.634 * 101.256 mN = 165.45 mN which is more than half of what the Chinese reported at 300W, i.e. around 270 mN per the 2013 NWPU data plot appended below, which tells me we could be in the right ballpark just using the M-E scaling rules and the metallic electrostriction response for force rectification in a frustum resonant cavity. Oh yes, and the metallic electrostriction response could be much more robust than crystalline dielectrics that have brittle failure modes that metals don’t have…

Remember folks, electrostriction is our friend…

Best,

Paul March
Principal Engineer
NASA/JSC/Eagleworks Lab

[birchoff]

It is part of the Standard Model that virtual particles pop into and out of the quantum vacuum all the time. According to Sonny, this is where the mass comes from and where it goes. The real trouble is that these are VIRTUAL, not real particles. There are so many of them, that if they gravitated, they would cause the universe to collapse from its own gravity. Obviously, they don't gravitate, which is what makes them "virtual". However, Einstein's Equivalence Principle says that gravitational mass and inertial mass are not only indistinguishable, they are the same thing. So if virtual particles can't gravitate, they can't transfer momentum either. If they can't transfer momentum, then they can't be used for propellantless thrust. Hence our trouble. Sonny's "theory" which certainly does not rise to the level of a scientific theory, makes no sense at all as it is a denial of EEP. This is why Sean Carroll at CalTech calls it "bullshit".

Invoking Dr. White's "Quantum Vacuum" ideas is certainly unjustified as yet (and an easy way to confuse the issue), but Paul's exploration of M-E Effects and electrostrictive impacts from chamber metals on Jim's distribution list yesterday was MOST interesting. The fourth power scaling of M-E mathematics is killer, and the math for thrusts is within the order of magnitude for the reported performances of the various species of em-drive.

Perhaps we now see an inspiration or two to significantly boost MET performance?

Hey is this distribution list publicly readable?

[birchoff]

not all of us have access to Jim's email list. Could you please summarize what Paul wrote?

X: “What puzzles me is the fact that with no dielectric, the tapered cavity produced no thrust, whereas it should have (according to Shawyer & the Chinese).”

When did they do a test with a tapered cavity (Emdrive Replica I assume) without a dielelectric that didnt produce thrust? The paper didnt include any of those results, unless my eyes wilfully skipped over that useful information.

[hanelyp]

The gravitational behavior of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. ...

I read about experiments being set up to test that years ago. Not seeing a followup I presumed a 'null' result of antimatter acting exactly like normal matter to within the precision of the experiment.

[Aero]

not all of us have access to Jim's email list. Could you please summarize what Paul wrote?

X: “What puzzles me is the fact that with no dielectric, the tapered cavity produced no thrust, whereas it should have (according to Shawyer & the Chinese).”

When did they do a test with a tapered cavity (Emdrive Replica I assume) without a dielelectric that didnt produce thrust? The paper didnt include any of those results, unless my eyes wilfully skipped over that useful information.

It's in the report, but only a few lines.

[Aero]

Can we discover the schedule for verification testing at other Labs? Do we know the high level protocol? Do they plan one device going round-robin to the other labs in sequence, or will they make 3 or more devices and send them out to the Labs?

If I were designing the verification program, I would make multiple devices as near alike as possible, and give them each a cursory test in-house before sending them out. And of course I would not send out a device that didn't work in-house.

The device doesn't seem to be that expensive or difficult to make, now that they have a good idea of what to make. It shouldn't take long and they did finish testing in the second quarter so they have had some time to prepare. Of course, contacting the Labs and identifying test sites takes time, but that step seems to be finished. Will NASA Eagle works Lab need to provide the power supplies too, or will those be available at the test sites? And how long does it take for the various IV&V test labs to integrate a new test program into their Lab schedule? Is the equipment generally available or is it like scheduling time on the space telescope?

I bet Paul March knows, or has a good idea ... when we might hear rumors from the IV&V labs. Or maybe readers here know people at the labs ...

[birchoff]

It's in the report, but only a few lines.

Wow, my eyes clearly missed that part. I wonder why this information wasn't included in the measured thrust table above it. There is definitely evidence in their results for the dielectric being an important part of the thrust generation. Would be nice to see the following

In Vacuum

• 1. Cannae slotted cavity with Dielectric
  2. Cannae unslotted cavity with Dielectric
  3. Cannae slotted cavity without dielectric
  4. Cannae unslotted cavity without dielectric
  5. Tapered frustum (EmDrive) with dielectric
  6. Tapered frustum (EmDrive) without dielectric

With all of the above going from low power to high power input.

[GIThruster]

That's an interesting wish list but do remember that each of these permutations have different impedances and therefore require different power systems or at least specific adaptations of any given power system. These things are not plug and play.

[GIThruster]

Can we discover the schedule for verification testing at other Labs? Do we know the high level protocol? Do they plan one device going round-robin to the other labs in sequence, or will they make 3 or more devices and send them out to the Labs?

I don't think NASA knows yet. There are rumors that Glenn is thinking about a validation study (it's not a replication when you use someone else's thruster) and that JPL has already considered this and decided its not worth their time. Don't put much stock in the rumors, however. Doesn't mean a thing until a thruster is on a balance.

Personally, I'd be thrilled to see whatever setup produced the most thrust sent around to 3 different labs for validation and perhaps look for thrust scaling with V. IIRC, M-E theory does NOT predict V^4 thrust scaling but V^2 scaling (quadratic). Not sure why Paul wrote V^4 except that he does have the habit of wanting to see QVF and M-E physics as opposite sides of the same coin.

[birchoff]

That's an interesting wish list but do remember that each of these permutations have different impedances and therefore require different power systems or at least specific adaptations of any given power system. These things are not plug and play.

Agreed, but the data collected from the entirety should provide enough information to either start informing a coherent theory or help find the experimental protocol error.

[birchoff]

Can we discover the schedule for verification testing at other Labs? Do we know the high level protocol? Do they plan one device going round-robin to the other labs in sequence, or will they make 3 or more devices and send them out to the Labs?

I don't think NASA knows yet. There are rumors that Glenn is thinking about a validation study (it's not a replication when you use someone else's thruster) and that JPL has already considered this and decided its not worth their time. Don't put much stock in the rumors, however. Doesn't mean a thing until a thruster is on a balance.

Ok I will start by assuming the rumors are true, big if.

*Gets on Soap box*
This is whats annoying. I can understand JPL has a list of other things it needs to do, but that list is not going to be infinite. So while a JPL validation doesnt have to happen ASAP, they still shouldnt turn their backs on it in perpetuity. It is this kinda politics (my interpretation), that lay people cannot stand. If this thing isnt worth your time, how about letting EagleWorks know why. How about calling out a few issues with the protocol described, so they can go back and update their protocol and collect the information you need to make it worth your time.
*Gets off Soap box*

The rant above is only valid in a world where JPL just flat out doesnt want to believe this is worth their time no matter what the data says. I am not saying thats what GIThruster is conveying.


Hopefully Glen and JHU pull the trigger on this.

[williatw]

Why NASA’s Physics-Defying Space Engine Is Probably Bogus


An artist’s render of the MAVEN mission, upon arrival to Mars. NASA

Here’s the tricky part: The laws of physics are called laws for a reason. It’s exceedingly unlikely that shooting off radio waves inside a carefully constructed can is enough to break one of them. It’s much more likely there’s some error in the experiment, something extremely subtle that no one has noticed yet. It’s happened before. In 2011, Italian physicists thought they had discovered neutrinos that could travel faster than light, contradicting Einstein’s theory of relativity. After extensive testing, the team realized it had flawed data thanks to a loose fiber optic cable. It’s likely that the results of the NASA experiment have a similar explanation

John C. Baez, a mathematical physicist at the University of California at Riverside, calls the experiment “graduate-level baloney.” He scoffs at the idea that microwaves in a “fancy-shaped can” could violate the law of conservation of momentum.

http://www.wired.com/2014/08/why-nasas- ... bly-bogus/

[tokamac]

There are already theories that don't break the laws of physics. We simply don't know yet if any of them corresponds to the EmDrive physics. I tried to sum up all proposed working principles for the EmDrive, the good ones and the bad:

• Radiation pressure: Roger Shawyer's explanation about radiation pressure due to different EM group velocities upon the two end reflectors of the tapered cavity seems to break conservation of momentum, even resorting to different frames of reference in special relativity.

• Lorentz force imbalance: Juan Yang at NWPU and Guido Fetta at Cannae LLC both refer to a Lorentz force imbalance acting on the lectron trajectories upon the two end reflectors of the cavity, using classical electromagnetism. Same breaking of the laws of conservation of momentum.

• Quantum vacuum virtual plasma: Harold "Sonny" White at NASA has a conjecture about Quantum Vacuum Fluctuations (QVF). He thinks the virtual particles that pop in and out of the vacuum state can be treated as a real plasma. So he tries to impart momentum on this virtual plasma using magnetohydrodynamics (MHD) i.e. a Lorentz force produced by crossed electric and magnetic fields that accelerates electrically conducting fluids. So White's Q-thruster is like an electromagnetic plasma thruster, except the propellant that is pushed back is a virtual plasma created from the vacuum by quantum fluctuations. The fact that momentum could be imparted to virtual particles is not proved and quite dubious though. The model predicts a force output scaling proportional to the E-field strength to the fourth power (V^4).

• Scalar-tensor theory: Fernando Minotti from CONICET explains that a scalar-tensor theory of gravity, of the Brans-Dicke type (proposed by Mbelek & Lachièze-Rey) would account for the thrust produced by RF resonant tapered cavities. Within this S-T theory, the thrust is the result of the gravitational force on the cavity walls. The metric tensor has a negative effective source. With the different EM resonant modes (TE or TM) in the cavity, the corresponding total effective source is zero, with differentiated regions where it is either positive or negative (the latter should thus be located as close as possible to the walls). Moreover this theory is compatible with an increased thrust due to the presence of a dielectric resonator inside of the cavity near an end reflector, which would distort the source distribution in the right direction. The effective source is proportional to the time average of B^2 – (E/c)^2
  S-T theory is easily falsifiable in the lab:
  - First, for fixed EM resonant mode and power, but different operating resonant frequencies, thrust could be higher with certain lower frequencies, and thrust should reverse for other frequencies. Those special frequencies can be precisely calculated, from cavity dimensions.
  - Second, still for fixed EM resonant mode and power, the thrust should increase with the mass of the cavity. One does not even have to change the cavity, but simply wrap it with a layer of some heavy material.

• Mach effect: James Woodward at CSUF has integrated Sciama's work about Mach's principle and Wheeler-Feynman "action at a distance" theory within the framework of General Relativity, that led to the description of relativistic Mach effects. This work led to experimental testing of propellantless Mach Effect Thrusters (MET) and a theoretical development involving Transient Mass Equation (TME). The TME could explain why an RF resonant tapered cavity like the EmDrive, with a dielectric material inside, would produce thrust when the dielectric increases its internal energy, storing energy from the microwaves. It could also explain why such a version of the same cavity lacking its internal dielectric would still produce a (smaller) thrust, due to the metal of the cavity walls which is weakly electrostrictive. The model predicts a force output scaling to the second power (quadratic).