June 2014 saw excited reports that NASA was working on a faster than light warp drive starship. Astonishingly, weeks later we are being told that NASA has also successfully tested a device which could push along a space vehicle without consuming any propellant. If true, this would be an astonishing discovery, not only violating laws which are cornerstones of science but also possibly allowing easy access to the worlds of the Solar System. But are these latest reports correct?

(For the latest developments in this affair see NASA’s Space Drive: the Plot Thickens (link).

In physics, momentum is a quantity obtained by multiplying a body’s mass and velocity (velocity is not just speed, it is speed in a set direction- an important distinction). Both theory and centuries of practice indicate that momentum is conserved; essentially meaning that it is never created or destroyed. Let me illustrate this with a pertinent example.

Imagine a spacecraft floating in empty space. Inside it are tanks of propellant, say liquid hydrogen and oxygen, and a rocket motor. When the craft’s motor is turned on, the hydrogen and oxygen are burned together in the combustion chamber, creating hot gases which are allowed to escape at very high speed out a nozzle, pushing the space craft forward.  Looking more closely, every second the motor operates, a relatively small mass of gas is emitted at high speed out of the back of the spacecraft as the exhaust. A small mass of gas multiplied by a high speed rearward yields a significant momentum in that direction. To balance the books (conserve momentum), the spacecraft must move with an equal and opposite momentum, so it shoots forward (its mass will be greater than the gas in the exhaust, so its velocity will be lower, but the spacecraft’s velocity will keep building up as long as the rocket motor is fed propellant. The spacecraft’s motion in response to the escaping propellent is termed a ‘reaction’. A rocket motor is a reaction engine (or “drive” in science fiction parlance).

Momentum conservation is predicted by Isaac Newton’s laws of motion (and in modified form Einsteinian relativity) and is observed throughout science and utilised in engineering all the way from collisions of subatomic particles to launching probes to the planets.

However, rockets are clumsy and inefficient; to accelerate to meaningful speeds vast quantities of propellant must be carried and consumed. Perhaps 90% of a rocket’s mass at launch is propellant, perhaps only 10% structure and payload. This is a sad fact, meaning rockets to send missions into to space must always be behemoths, suggesting space travel will forever be difficult and expensive. What if there was an easier way? Could there be entirely new physics (or “loopholes” in existing physics) permitting a “reactionless drive” which would run solely on electric power without carrying any messy and bulky propellant ? A spacecraft with a reactionless thruster would be a space enthusiast’s dream, rising silently into the sky without the sound and fury of a rocket launch, permitting a probe or even a spacecraft with a human crew to roam the planets. Unfortunately this seems impossible. Yet some disagree.

Dozens if not hundreds of concepts for reactionless drives have been proposed, the vast majority being the fantasies of science fiction authors or crackpots or the lies of scammers. However, this is not always the case. Roger J. Shawyer , a British aerospace engineer with impeccable professional qualifications has proposed a device he calls an EmDrive.

Shawyer’s EmDrive thruster is a magnetron, a microwave generator, inside a specially shaped, tapering resonant cavity whose area is greater at one end. Both ends of the cavity are sealed. Essentially an EmDrive unit is a metal can with a microwave source inside. When it is turned on, the EmDrive’s magnetron emits microwaves which bounce around inside the cavity pushing against its sides. According to Shawyer, thanks to the cavity’s shape there is a slight imbalance in the pressure exerted by the microwaves which manifests as a thrust, hence the thruster moves without emitting any exhaust. An alternative name for the concept is RF resonant cavity thruster.

Electricity is apparently being turned directly into thrust in defiance of the conservation of momentum law. Shawyer believes that his concept’s behaviour is permitted under Einstein relativity (hence the device is actually called a “relativity drive” by some) and he insists it obeys Newton’s laws and conserves momentum. He has written highly mathematical papers to justify this and claims to have successfully tested prototypes. Eureka magazine’s website has a video of an EmDrive being demonstrated.  Shawyer has created a company (with the help of a £45 000 grant from the UK’s Department of Trade and Industry) to develop this technology. Shawyer has shared his beliefs on the theory and potential of his device in a series of videos.

 

Shawyer’s proposal has received some positive coverage in engineering journals and websites but not from many scientific publications (apart from New Scientist, which positively gushed enthusiasm). The science community has been largely reluctant to repeat Shawyer’s research because his theoretical justification sounds frankly absurd. All electromagnetic waves, such as microwaves, possess momentum. This means that a beam of microwaves does indeed exert thrust and you could actually make a grossly inefficient rocket based on the principle of an exhaust of microwaves alone (it would in fact be a form of photon rocket), but that is not what Shawyer claims to have invented. The microwaves are trapped in his device, and do not escape as an exhaust, making it reactionless.

Take one of those little RC helicopters you can fly indoors. Imagine getting an incredibly light-weight cardboard box, putting the helicopter inside and sealing the lid before turning the helicopter on. Will the box rise into the air thanks to the spinning rotor inside? This is  comparable to what Shawyer claims his device does.

Since I wrote the above paragraph I have read Shawyer’s document A Note on the Principles of EmDrive force measurement, which muddies the waters considerably. In it Shawyer claims his device cannot generate thrust when at rest, instead it must be in accelerating motion. If correct this means that you cannot measure an EmDrive’s thrust by it placing in on a balance (Shawyer explicitly states this), instead it must be accelerated by an external force while the measurement takes place. This is both inconvenient for experimenters and really odd physically.

The physics community mostly believes Shawyer is profoundly mistaken (laying my cards on the table,  I would agree with this opinion). However if a prototype were to be tested in space conditions and work as advertised then physicists, scenting a Nobel prize, would really pay attention.

Other experimenters have indeed attempted to duplicate Shawyer’s research. The Boeing aerospace company has investigated Shawyer’s technology but this does not seem to have led anywhere. Juan Yang , a professor of propulsion theory and engineering of aeronautics and astronautics at Northwestern Polytechnical University (NWPU) in Xi’an, China, claimed to have tested a high power EmDrive on a rocket motor test rig in 2010. Yang’s published data suggests the EmDrive passed its tests with flying colours, but she has not convinced many others to revisit Shawyer’s brainchild (see updates at end of article).

Another inventor, Guido P. Fetta has suggested a similar device to the EmDrive that he has called the Cannae drive (confusingly also known as the Q-drive). Fetta, with a “background as a sales and marketing executive with more than 20 years of experience in the chemical, pharmaceutical and food ingredient industries”, owns a company called Cannae LLC to exploit his research. Although the Cannae device is also essentially a metal can with a microwave source inside some report that it is intended to operate under entirely different principles to the EmDrive perhaps exploiting quantum mechanics to violate the laws of classical physics. I cannot verify this as the Cannae website  has nothing to say about it.

The Cannae device is a thick disc-shaped resonant cavity with radial slots in one inside face, according to its inventor these are vital to produce an internal force imbalance leading to an external thrust. I recommend everyone read the patent for the Cannae device which discusses how it could be applied for “energy harvesting”, suggesting Fetta believes he has also invented a free-energy device. This makes the concept self-confessed nonsense.

Bringing the story up to date, in 2013-14 a team from NASA’s advanced propulsion thinktank, the Eagleworks Laboratories, tested Cannae drive and “tapered cavity” devices with interesting results. These were published in the paper Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum. The experimenters describe how they placed drive units on a torsion pendulum capable of detecting thrusts  “at a single-digit micronewton level” in a stainless steel vacuum chamber.  When the Cannae devices were supplied with around 30 watts of power, the tests measured them to generate 30-50 micro-Newtons of thrust. These are  fantastically small forces, equivalent perhaps to the weight of a sand grain, measuring them alone is an achievement as the environment is full of noise (such as the footsteps of passersby) that could swamp this signal .

The experiments with the tapered cavity device (which is not called an EmDrive in the paper) found that “the presence of some sort of dielectric RF resonator in the thrust chambers” was essential to observe a thrust from the device. When it worked the authors saw an average thrust of 91.2 micro-Newtons generated for an input power of about 17 watts. This means this device has a “thrust to power ratio” of 5.3 micro-Newtons per watt, this statistic is rather esoteric , but it will be important later.

After describing the experiments and their results, the paper suggests refinements to both the authors’ techniques and their equipment for further investigation. The team’s paper ends by discussing in detail possible human space missions to the moons of Mars and Saturn that would be possible if a reactionless drive based on improved scaled up versions of their test articles were to be used. To space buffs and science fiction fans (and I am both) these projected voyages are a mouth-watering prospect.

The report suggests an operational reactionless thruster to take human explorers on round trips to Saturn's moons such as icy Enceladus. (Image credit: NASA)

The report suggests an operational reactionless thruster could take human explorers on round trips to Saturn’s moons such as icy Enceladus. (Image credit: NASA)

 

Despite the tiny measured thrusts, this is a startling announcement. The NASA researchers seem to have found a flaw in a centuries old central dogma of science, opening the possibility of a wonderful new era of interplanetary travel. This seems to be news worthy of the attention it is receiving. Sadly it is not as simple as that. In fact I am rather dubious and here are my reasons to be sceptical.

  • The researchers describe the vacuum chamber used in the experiment in a lot of detail (in  the section “II. Thrust Measurement System Torsion Pendulum” of their paper), yet the testing was not actually conducted in a vacuum, rather with the vacuum chamber “door closed but at ambient atmospheric pressure”. This was because the capacitors used in the test devices could not survive vacuum conditions, I presume this was a last minute discovery but the test programme went ahead regardless. The section “VI. Summary and Forward Work” recommends that future tests be performed in a vacuum. Not performing these tests in a vacuum is a serious blow to the experiment’s credibility. The slightest air current could interfere with so slight a measurement.  I originally suggested that the electrical current fed to the drive device was generating heat which caused convectional air currents, moving the device on its pendulum. The paper seems to indicate thrust occurs instantly when the power is applied and drops immediately to zero when the power is cut off. That seems to suggest the device is not effected by self-generated convectional currents.(UPDATE: in February 2015 one of the Eagleworks team, Paul March, reported the tests have now been repeated in a vacuum obtaining measured thrusts of about 50 micronewtons, March says if they can obtained thrusts of  at least 100 micronewtons there will be attempt to replicate these results at NASA’s Glenn Research Center.)
  • The research team also tested a Cannae device designed to accept electrical power but not to function as thrust-generating unit. To make it inoperable it was manufactured without the slots its inventor believes to be essential for its operation.Yet the team measured a force generated from this device too! This non-functional device was not an experimental control, instead the researchers also tested an RF load with no functioning components -a resistor – and indeed measured zero thrust for that test. It is extremely odd that a device designed by its creator to be inoperable “works” just as well as “functional” devices.
  • The team suggest this is not actually reactionless propulsion (indicating that they know how outrageous this would be) but rather momentum is being transferred “via the quantum vacuum virtual plasma”. This sounds profoundly impressive but it is also scarily like Star Trek-style technobabble. To the best of my knowledge quantum mechanics predicts that all space is permeated by “sea” of virtual particles but I have never seen this described as “plasma” before. It is also intriguing that this hypothesis has absolutely no common ground with how Shawyer claims his EmDrive should work. Shawyer says an EmDrive must be accelerated by an external force while the measurement takes place- so according to him the NASA experimenters should not have seen a thrust from their stationary devices!
  • Harold White, a team member, has, shall I say, form in presenting his team’s research in a prematurely positive way.
  • Most damning in my opinion, is the reported “thrust to power ratio” of 5.3 micro-Newtons per watt. Say the device was not a closed cavity after all and instead just squirted out microwaves. As mentioned earlier, the microwave beam would actually act a rocket exhaust. You can calculate the thrust to power ratio of such a beam, it comes out as 3.3 nano-Newtons per watt . This very low efficiency is a consequence of physical law and is the best that can ever be achieved. Yet the NASA team claim to have observed an efficiency about 1500 times greater! This is seems impossible.

While I’m at it, can I also clarify some misconceptions about this technology:

  • It is not an anti-gravity device
  • It is not in any way based on the work of Nikola Tesla
  • It is not based on “flying saucer” technology
  • It doesn’t prove “Einstein was wrong” (on reflection, actually it does)
  • It has nothing to do with “Electric Universe” Theory (don’t even ask!)

I would love this to be real, as it would be the greatest step forward in space travel ever, sadly over the years I have seen so many such steps come, go and disappear without a trace. Once again I am sorry to throw cold water on so exciting a story but in short, the concept of reactionless propulsion is still as impossible as it has ever been. NASA has not overturned Newtonian dynamics.  A small-scale research project inside NASA has tested a device based on exotic, if not fringe, science, claimed to see anomalous results and placed these forward for scrutiny. Perhaps more research will show this to be nothing real or even verify these findings with exciting results. Let’s wait and see.

UPDATES: In July 2015 researchers in Germany reported further inconclusive tests on a EMdrive style device. Although some excited reports have claimed this proves the device’s validity, the authors claim their test do not confirm or refute this.

In 2016 Yang et al. apparently published a paper reporting that a greatly improved experimental setup failed to observe thrust from their devices.

In November 2016 White et al. published a paper Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum describing a test program with their devices in a vacuum, reporting 9 measurements of thrusts in the 30-119 micro-Newton range and proposing this effect to be a consequence of  pilot-wave theory, a unconventional interpretation of quantum effects. I am eager to see if these results can be replicated by other researchers.

(Article by Colin Johnston, Science Education Director)

(Last update 4 November 2015)

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141 Comments

Aetzbar · February 26, 2016 at 10:23

(Content removed- sorry but I cannot let you post what is clearly just an advertisement for a book here- ADMIN)

NelMac · February 24, 2016 at 17:21

It’s great to see this debate is still ongoing. I’d hate to be deemed as ‘stating the obvious’ but there are a lot of very simple methods of dis-crediting the E-M drive nonsense.
Sit on a bike, push the handlebars…..did you and or the bike exhibit a change in momentum ?
No, it/they didn’t.
Relatively, of course, the source of the force will experience momentum, (i.e. you could push yourself off the saddle, travelling backwards and landing on your bum, (if the bike was heavier than the individual pushing it), however, the bike will get pushed away and you will remain exactly where you were as the energy would always be divided between the two resulting in more force conversion in one than the other.
Personally, I was a subscriber of New Scientist for many years, until….that article was published. The moment, (pardon the pun!), that article was published, I laughed so much I could no longer read another word in ANY of their articles without a degree of annoyance.
On another note, the ridicule that exists with the measured ‘results’ and the quantity of energy required to produce the results further increases the chances that the whole experiment was somehow misinterpreted. It would signify that, if I use my microwave oven for 1 hour every day, then, after a year or so it should have travelled somewhere !
Albeit, nano-meters.
Nae chance !

k robinson · February 8, 2016 at 20:18

Dear Admin, Having spent a lot time reading as much as i can find on these “closed box, cone shaped, microwave powered thrusters” (can i call them that?) I must say that this article and the comments are the most balanced I have come across and you are a very good admin who takes on board critics, advocates and even sci fi nuts….. But lets face it, even although the microwave thrusters may violate the laws of physics (as we know them to be) they do seem to work. They have been tested in a vacuum, the results have been replicated by others. Even Diy projects are getting the same results. The whole argument that the designers don’t agree, or don’t know how they work is irrelevant, science is littered with accidental discoveries (if Percy Spencer hadn’t walked in front of a magnetron in the first place,thus melting the chocolate in his pocket and inventing the microwave oven I doubt we would be even discussing the thruster), so more testing must be done even if there is a 1 in 1000 chance of success, and lastly as I have trawled through all the comments on multiple articles, the interest generated and observing the layman (and women) interacting with proper science types on such an important topic makes it all worth it even it all turns out to be a load of rubbish… it’s got to be more productive than swapping catphotos on facebook. Thanks for your effort. dstormer23

k robinson · February 8, 2016 at 19:44

(Duplicate post-ADMIN)

Kelly Manning · January 2, 2016 at 00:39

Yawn, the fact that photons, including microwave photons, have momentum, used to be taught in high schools back in the 1960s. Have things gone down hill in schools?

http://study.com/academy/lesson/energy-momentum-of-a-photon-equation-calculations.html

The Pioneer 10 and 11 probes have been experiencing photon emission thrust for decades.

http://spectrum.ieee.org/aerospace/astrophysics/finding-the-source-of-the-pioneer-anomaly

“The magnitude of the force was still tiny by Earth standards—about the same as the backward push your car experiences in reaction to the photons spit out by its high-beam headlights.”

This is the same principle as “Solar Sailing” with thrust generated by reflecting sunlight.

So much for violation of the law of conservation of momentum. Thrust from microwave photons leaving a cavity resonator is no different from thrust atoms leaving a combustion chamber or visible light leaving a headlamp.

    admin · January 4, 2016 at 11:07

    Dear Kelly, thank you for your comments. Note in the article that I said

    …a beam of microwaves does indeed exert thrust and you could actually make a grossly inefficient rocket based on the principle of an exhaust of microwaves alone (it would in fact be a form of photon rocket), but that is not what Shawyer claims to have invented. The microwaves are trapped in his device, and do not escape as an exhaust, making it reactionless.

    All the theorists and experimenters involved with this research claim that no microwaves should escape from their devices.

    I also point out that the claimed measured thrust values are grossly larger than would be exerted by a microwave beam of the stated power.

lvslvs · November 7, 2015 at 05:13

If the microwaves bounce back and forth 1500 times before being absorbed, the 3nanoNewton to 5.3microNewton difference goes away. In most of the experiments I saw detailed, the power source was not actually in the resonator, but was outside and fed power into the unit. This would cause the power fed in to push away the resonator from the power source by 3nN per watt – if it was totally absorbed. If as is usual in many microwave set ups, there is reflected power, then all the reflections count too.

Feloneous Cat · November 4, 2015 at 15:17

“Not performing these tests in a vacuum is a serious blow to the experiment’s credibility. The slightest air current could interfere with so slight a measurement. I originally suggested that the electrical current fed to the drive device was generating heat which caused convectional air currents, moving the device on its pendulum. The paper seems to indicate thrust occurs instantly when the power is applied and drops immediately to zero when the power is cut off. ”

Let’s dissect this: if the device was generating heat (which was mistaken for thrust) the temperature of the device will not immediately go to zero once power is removed.

But let’s assume that there is heat. The rise and fall will be 90 degrees to the device being tested (most thrusters and engines are tested parallel to the Earth). However, again because air molecules are nasty beasts, as soon as the power is cut they are still going to rise and fall until the device reaches room temperature. Not when power is established or cut (because objects take time to heat up and cool down).

Yet this is at odds with what is reported. So either your theory is wrong (and, frankly, it is at odds with Newtonian physics as well) and something else is happening or the damn thing works (which would be annoying as hell).

But your air current theory is, to be blunt, incredibly weak.

    admin · November 4, 2015 at 16:54

    Dear Feloneous Cat, thank you for your comments. I note that you did not include my very next sentence when you quoted me. For the record it was “That seems to suggest the device is not effected by self-generated convectional currents.” I hope you can see that I withdrew my suggested explanation when I saw evidence suggesting that it was not correct.

MouseTheLuckyDog · November 4, 2015 at 07:58

The claim that the thruster can only work when it is moving is ridiculous. Simply observe the thruster in it’s rest frame, and there will be no thrust. Then change to the reference frame where thrust is produced. Again there must be no thrust.

In fact it sounds like a SR101 quiz question: A rocket experienced no thrust in it’s rest frame. How much thrust does it feel in a reference frame moving at 200 mph with respect to the rocket?

    admin · November 4, 2015 at 09:56

    Dear Mouse, the “no thrust unless the thruster is being accelerated by an external force” idea is from Roger Shawyer not me! It is in his more recent writings.

James Wadsley · September 29, 2015 at 21:43

They could have made an electromagnet. Anyone wanna bet the vacuum chamber is made of steel?

Kay · August 21, 2015 at 23:44

Nice article, too bad you’re confusing 2 entirely different propulsion systems.
The one is indeed the asymmetric microwave refection drive, the other however is a mhd drive that works without material plasma and uses empty vacuum instead (and in that the “vacuum plasma” aka “virtual particles” from the “Dirac sea”). There’s no real plasma of any kind, yet there is (very little) thrust.

    admin · August 25, 2015 at 07:25

    Dear Kay, I am sorry but I was reporting on the Eagleworks, Fetta and Shawyer research using their descriptions and terminology. Note that the Eagleworks tested an asymmetric microwave device but seem to claim that it is a “mhd drive that works without material plasma and uses empty vacuum”!

Gravitomagnetic London Moment · August 3, 2015 at 22:47

“the concept of reactionless propulsion is still as impossible”

did you forget that in the very YouTube i link here , he/they never once calls these devices “reactionless” propulsion, in fact he states it is NOT reactionless as that is not credible ,he also points to the mathematical formula’s that balance the equations…

as far as i can tell only 3rd party commentators ever reference these test apparatus as “reactionless” to hang their straw-man off…..

    admin · August 4, 2015 at 07:58

    Dear GLM, thanks for your comments. Sorry, I don’t see the link you talk about. However, regardless of whatever anyone says, the devices tested by NASA Eagleworks would be reactionless thrusters (if they worked). I think some of the theorists and experimenters downplay this this as they know how outrageous it sounds (hence Eagleworks’ claim that the devices are reacting against the “quantum vacuum virtual plasma”).

Claudio · May 22, 2015 at 15:30

After reading blogs: I am very surprised to see how commenters think facts without a theory are impossible or cannot be credible. I thought physics, as I studied it, was based on experiments…
The issue with this drive is whether or not it generates thrust “as claimed”, i.e., without contributions from air currents, buoyancy, photonic thrust, stray RF energy, etc..
Resorting to analogies to prove it or disprove the effect (e.g., a toy helicopter in a closed box) is not science.
Clean experimental data can resolve this issue, just as they did with the Pioneer Anomaly.

Jonathan Langdale · May 13, 2015 at 12:35

I just wanted to point out that everything on the Earth’s surface is under constant acceleration due to the gravity well which contributes to the Earth’s angular momentum. Stationary is only a valid concept relative to each other. But even then this is an approximation since the Earth’s plates are moving. So a vacuum chamber never removes acceleration.

    Feloneous Cat · November 4, 2015 at 15:21

    In other words, when you are talking about stationary, what is your reference point?

Oleg · April 3, 2015 at 16:07

Russia successfully tested antigravity engine by Leonov…(2013 words removed -ADMIN)

(Dear Oleg, I am afraid your comment is excessively long so I cannot approve it. -ADMIN)

Edward Cox CPP · March 31, 2015 at 06:31

Testing of this device must be done in an RF dead environment. Any resonating cavity can also be invaded by external RF at primary and Harmonic frequencies. Testing in anything other than an RF containment brings about the possibility of External RF skewing the research and skewing the thrust measurements. An environment where the resonant cavities frequenciy might actually interact with outside stray RF energy could unintentionally introduce RF harmonics interactions that just might negate the experiment entirely. The Chinese labs results indicting hundred of newtons may just be a result of this error in setting up an experiment in an RF rich environment. a lot of 2.4 GHZ energy out there from Cell phones, towers etc..

Ri Zen · March 3, 2015 at 16:05

If it can be proportionately stepped up and applied, it would theoretically be possible to float a nuclear powered submarine with the reactor power it already produces…wonder how military subs would handle space… 😀

El Fitz · February 25, 2015 at 00:50

Hi there !

I’m no physicist or engineer, merely a college drop-out… But I do have two things to say.

First of all, all these comments are just as interesting as the original post. And I seriously mean it. Second, well… You, Mr Colin Johnston, are someone remarkably honest and open-minded, accepting being both criticized and pointed your mistakes. Which really is, I’m going to say it once more, remarkable.

Now, having completed high-school with a heavy focus on science, I can only agree that these results are quite surprising and need further experiments in order to be proven. Let’s wait and see. Worst case scenario, some people will have waisted a little time and money on something that seemed to be highly unlikely, but both greatly inexpensive and easy to try out, with some thin evidence that it could possibly lead somewhere. Who cares ? Ain’t much of a scandal or tragedy. What is, however, annoying, is how some are getting excessively emotional over this (and yes, I’m talking about the Verge, Wired,… as well as those who are simply calling this a waste of time).

I wouldn’t get my hopes too high, sure, and they better come with some much more solid evidence next time. For now, I’d say that no matter what end result may be, this is greatly interesting.

William · February 19, 2015 at 04:17

I am not involved in any of the em-drive / cavity propulsion research projects but have been following it closely for a couple of years. A lot more information has become available in the last 6-8 months and has shown up on the NASA Space Flight advanced topics discussion forum. To those who say a thrust has been measured so therefore the effect is real I would say there is a lot of uncertainty about the measurements. The Houston group has provided the most detailed information about their tests, measurement techniques, etc. I believe they are making a good faith, honest effort to understand what is happening but there are alternative explanations for their results. It is not possible to directly measure very small forces on the order of a few micro Newtons with strain gauges, springs or other well behaved sensors. My understanding of the torque pendulum they are using is that it is similar to balancing the whole cavity, etc on top of a thin flexible beam. If a force is generated the beam will bend ever so slightly. This is detected by a correcting mechanism and a counter force is produced that keeps the beam in its original position. This system is calibrated before each test. One alternative theory proposes the RF energy heats the thin Copper on the large endplate, causing it to bow in (oilcan effect). This very slightly changes the Center of Mass of the apparatus, which is registered as a force. A detailed analysis of this theory is available on the first em-drive thread- The experimenters at Eagle Labs don’t seem to be very interested in performing counter experiments. An earlier post decried this but it is as important as positive result experiments. Both are part of the scientific method. The only baseline or counter experiment they have disclosed was when they put a dummy load on the RF amplifier and measured no force. But the dummy load was outside of the cavity. So far they have not heated the inside of the cavity to see what that would do.

Shawn Kearney · February 16, 2015 at 09:10

I am really having a very hard time understanding your skepticism in places. Certainly claims like this deserve skepticism, but yours here seems more a result of bias than genuine, reasonable logic.

The first example that caught my attention is that you are skeptical because the null unit that was “not supposed to work did” does not suggest that neither worked, but rather that the slots are fundamentally unnecessary. This suggests that Cannae does not appreciate how the drive generates thrust – which seems OK to me, since if it does generate thrust nobody else does either, including (by your own insinuation) does NASA. However, simply because we don’t exactly know how something works does not mean that we does not “work”. High temperature superconductors we don’t fully understand how they work, yet nobody is doubting that they do. The physics of bicycles even didn’t need to be completely understood to work. Early hot air balloonists thought that there were lighter than air particles in smoke, and added smoke-producing additives in order to achieve more lift.

This assessment seems to assert that a functional theory must always pre-exist experimental results, when in reality the opposite is often true of the most important discoveries throughout history.

The next point of skepticism is that you blatantly assume that the experimental drive MUST be somehow leaking energy and that as a result this MUST be the reason why it’s producing thrust yet you even conclude that it’s producing too much thrust for this to be true, and as a result of that then the researchers, both in China and in the US must certainly be incorrect.

Now this logic really has me scratching my head. The drive has positive results that cannot be explained through being a mistaken photon rocket, yet you use this result as evidence that skepticism is warranted because it’s not the result that your bias anticipates.

If the drive works, then your skepticism that the drive does not violate the laws of physics is correct. However, what remains very unclear about all this is that if if does work, to what extent do we need to rethink the laws of physics? I am inclined to think that we do not need to rewrite the conservation of momentum. However, what strange interactions exist with high frequency electromagnetic energy in specifically designed closed containers might have to be rethought. If the drive *does* work, as it is currently looking like it might be, then literally anything could be causing it, from the probable to the highly improbable, such as dark matter interactions or, hell, the bending of the fabric of space itself.

Not that I think it’s actually a warp bubble, mind you, but when you completely do not know what’s causing a phenomenon it could be literally anything from the misunderstanding of fundamental physics to something completely yet known.

    admin · February 16, 2015 at 11:19

    Hi Shawn, I repeat again that I will be delighted if this is proven to be real and leads to a revolution in space travel. But I’ll also repeat my reasons for scepticism.

    If these devices move without emitting anything they are violating the law of conservation of momentum. We have never observed any phenomena which violates this and in fact a lot of science and engineering depends on this being a rigid law.

    Shawyer seems to have an incoherent, hand-waving theory on why bouncing microwaves inside a box gives thrust. The Cannae people seem to have a completely different incoherent, hand-waving theory on why bouncing microwaves inside a box gives thrust. I would be happier about this if these were competing explanations to rationalise observed behaviour rather than the theory underlying how the device works.

    The Eagleworks experimenters are measuring tiny thrusts near the levels of experimental noise but immediately suggest a third incoherent, hand waving theory to explain this, then leap to creating mission plans for voyages around the Solar System.

      Shawn Kearney · February 17, 2015 at 04:48

      I agree. If it’s pushing against nothing then it does violate the laws of physics as we know it, but again, simply because we cannot see the mechanism does not mean it’s not there. I certainly do not believe that the “laws of physics are being violated”. If it did, it wouldn’t work, so that’s just silly.

      If it does produce thrust, there has to be something rational going on. Either our understanding of the law of conservation of energy is fundamentally flawed (kind of unlikely) or something about our understanding about EM fields in what appears to be a closed box.

      We agree that Shawyer and Cannae’s explanation must be wrong and I don’t understand enough about Nasa’s explination to have much of an opinion. But this doesn’t impact the observations from both the Chinese and American experiments.

      Last, can you please cite your assertion that “The Eagleworks experimenters are measuring tiny thrusts near the levels of experimental noise”?

      According to one article “the equipment can measure forces of less than ten micronewtons, and the thrust was several times that high.” (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive). That article claims that even waves on the gulf coast 25 miles from the facility are accounted for. I’d dare say that if this is accounted for, I’d think that they likely weren’t so sloppy to confuse the crunching of corn chips or something.

      Also, the Chinese claim to have produced over 700 millinewtons with experiments of input power in the kilowatts (I don’t know if this was performed under vacuum).

      This isn’t to say that the results are certainly valid, but being that they appear to have been replicated by Shawyer, the researchers in China and now twice by Nasa (once under hard vacuum), it *seems more likely* at this point that the drive does produce thrust than it doesn’t, this is regardless that nobody seems to have a satisfactory reason why.

        admin · February 17, 2015 at 08:31

        You’re right, my comment about the measured thrust being close to experimental noise was incorrect, and I’ll remove it.

Jeremiah · February 9, 2015 at 04:18

A recent update suggests successful measurement of thrust signature while the test device was in a hard vacuum environment:

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608

    admin · February 9, 2015 at 09:50

    Dear Jeremiah, thank you for making me aware of that. I have added this link to the article.

john rogan · January 29, 2015 at 00:43

the magnetic field created at the earth’s core is what causes the magnets inside an electric motor to spin. the moon has no such magnetic field emitting from its core…doubt an electric motor would even work on the Moon…not even sure about batteries.

    admin · January 29, 2015 at 08:03

    Dear John, I’m sorry but electric motors are in no way reliant on the presence of the Earth’s magnetic field, why do you think that? Dozens of spacecraft with electric motors have operated far beyond the Earth’s magnetic influence, including on the Moon.

    I can assure you that batteries, which convert stored chemical energy into electricity, will work on the Moon or elsewhere in the Universe.

    I don’t see what your comment has to do with this article, did you mean to post it elsewhere?

tonyon · January 28, 2015 at 22:14

…need hyperluminal SPEED and TIME of the Immortals (3D Bioprinting…Telomerase…) to conquer SPACE…

Oleg · January 26, 2015 at 00:06

Russia successfully tested antigravity engine by Leonov
http://okomov.livejournal.com/577.html

James Earley · January 23, 2015 at 02:22

One article that I read claims that the Chinese test, run at 2kW, produced 0.7N of thrust. That is easily measurable. Even at the low power test run by NASA, why did they not do something akin to a Cavendish experiment that would have allowed them to measure a very small force? I can think up a few ways that this could have been arranged and settled the matter, without need to use the torsion pendulum and the problems of the capacitors.

    admin · January 23, 2015 at 09:08

    Dear James, thanks for your comments. I agree with your question.

    There are several other mysteries about this affair which continue to intrigue. To me it seems odd that the magnitudes of the thrusts reported by Shawyer, the Chinese researcher and NASA Eagleworks seem incompatible, how can this be explained? How can NASA Eagleworks test a Shawyer-style device but appear to believe it operates under completely different principles?

Lawesty · January 22, 2015 at 14:36

http://www.emdrive.com/IAC13paper17254.v2.pdf download and bask in the amazing. This proves it is:
1)Not breaking any laws
2)True
3) No one looks anything up and relies on 300 year old assumptions. Have a great new year

    admin · January 23, 2015 at 11:55

    Hi, thanks for the link. Having read Shawyer’s document, I would say it proves it is:
    1)Not breaking any physical laws according to Shawyer
    2)True according to Shawyer
    3)After 300+ years Newton’s law still stand until someone proves otherwise.

Fiordo · January 19, 2015 at 16:58

You went from “No!” to “I’m skeptical…let’s wait and see” in one article…all while throwing cold water on the theory, without actually addressing the experimental results.

I’m skeptical of this technology, but I’m certain that you are passing yourself off as something you are not.

    admin · January 19, 2015 at 21:17

    Dear Fiordo, thanks for you comments. To make my position as clear as I can:
    1. The article was written in response to articles hosted elsewhere with titles like “Nasa validates ‘impossible’ space drive” and “NASA tested an impossible space engine and it somehow worked”. I hope you agree that neither of these are correct.
    2. The theories behind the devices that the researchers tested are confused and incompatible with fundamental physics.
    3. The results obtained by the researchers are piteously weak evidence for new science.
    4. Purely because I assume scientists and engineers employed by NASA must be be honestly and accurately reporting their results and also if this is real it would a “game changer” for space travel I am eager to see further research to verify this.

    I’m certain that you are passing yourself off as something you are not.

    I do not understand what you are trying to say here. If any of the content of this article is inaccurate please let me know and I will correct it.

Grok · December 22, 2014 at 23:40

When were you first diagnosed with narcissism?

Duane Eddy · December 19, 2014 at 21:46

Suppose I have a cylinder with a reflective interior and I am able to cause a standing wave because the length of the cylinder is the correct for my wave frequency. I have a node at both ends so no energy hits either end.

I do not think anyone will have a problem with this.

Now I will shorten the cylinder 1/2 wavelength so I have a standing wave with a crest at one end and a node at the other.

I will get a thrust toward the crest end.

each time the wave travels from one end to another it will be 1/2 wavelength short causing the crest to form on every other end or one end will have a crest and the other will have a node.

The wave will be absorbed eventually but if we keep feeding it we will get many cycles before it is eliminated multiplying the impact on the crest side.

It may be that our problem is we model the microwaves as particles (which they are sometimes) and forget they also may exhibit wave properties.

So why would you propose this will not work?

Duordi

LOUIS RANCOURT · December 15, 2014 at 17:21

hi
Another way to look at the possible results of the em drive tested. An ongoing experiment shows that regular light moving horizontally can change the weight of an object. When the test mass is placed above a 4ft by 4ft aluminum box where 63000 lumen is going horizontally, the test mass gains weight and when it is placed under the box, it loses weight. It seems that light can interact with what causes weight. The em drive used microwave and this is also light at a lower frequency. It is possible that the microwave interacts with the source of gravity, thus creating a small force. That does not violate any laws of physics. The only problem is when in space far from a planet, is the difference of gravity that is shielded by the light enough to move a space craft?
More details on the results of that experiment at GRAVITYFORCES.COM.

Starfall · December 15, 2014 at 07:04

Admin –

I see quite a bit of criticism by you against the EmDrive and similar apparatuses. Because of much wishful thinking and the tendency of people to dive at anything fantastical, I can certainly understand reticence, but I think some are taking it a bit far in the criticism. Saying it’s wrong is one thing, but trying to insult it just to try and show how ‘wrong’ one thinks it is, is another.

In an earlier comment, you posted the following hypothetical: “Interaction with the Spirit World offers the potential to transfer momentum to space vehicles without this propellant mass fraction penalty, similar to the way a naval submarine interacts with the water which surrounds it.”

To answer your question, no, I wouldn’t accept that, but that also isn’t what they said. We can call what they said “technobabble,” and accuse them of making things up, but if you’re dealing with something you know you don’t entirely understand, but can see the results of, you need to call it something. If someone discovers a new planet, and they can see the new planet and observe it, are you going to disbelieve they found it just because they decided to name it “Bob” because it’s an unrealistic planet name?

Now, discovering a planet is a lot different from something which, at first glance, appears to violate something we’ve never seen broken. It’s possible that there are faulty instruments, even if it has been conducted by multiple facilities and teams. But I don’t think it’s so perilous an investment that it shouldn’t be investigated further. The best test is, frankly, to build one and see if it flies (or doesn’t). Considering the relative simplicity of the setup, it shouldn’t cost very much to build one someone earlier termed a “micro satellite” just to see if it’d work.

The real tragedy? It’d be if some jerk decided to purposefully make one fail because he wanted to be right about the drive being “wrong,” and cutting short a potentially fantastic discovery.

I know for some people, calling it a “discovery” might leave a bad taste in their mouths, but let’s be honest. The team had an idea of how it might be working. Are they absolutely correct? Did they maybe try to invent terminology for it (who wouldn’t if they were faced with the same thing)? The answer to both of those questions could be yes or no. But if thrust was observed, regardless of what caused it, thrust was observed.

The scientific thing to do is not throw it out, but challenge it. Put it under strenuous observation, do test after test after test, but don’t abandon it or shove people away from it, trying to make the ones who presented their findings look like frauds.

I admit, I want to believe it. Probably a lot of people do. I’m afraid of it being wrong, but I’m also prepared for it to be wrong. What bothers me is seeing people try to cut it short before it has a chance because it doesn’t necessarily fit with – not just their ideas of physics – but their own ideas of IT, the EmDrive itself. It is possible that it is literally pushing against space itself, or having a quantum field effect that produces thrust and by that means doesn’t violate conservation of momentum. I strongly suspect that’s why they described it as a propeller in water.

It would require a pushed object, a medium that could pass through said object, and a “propeller” that could bridge the gap and push against both. Weird, but then, we’ve discovered a lot of things in quantum physics that’s weird. I’m not quite ready to rule it out, and I am ready to thank my happy stars if we accidentally tripped face-first into the “Star Trek” age. Granted, we don’t have any shields to modulate yet 😉

It’s also possible, if it is still producing thrust, that they stumbled on an unknown feature of quantum field effects or mechanics that we simply weren’t expecting to find. They could be completely wrong in their explanation, but completely right in their observation, which is also probably why they were reluctant to go into details as to how it worked, especially if uncertain.

So where does that leave us?

Sitting in your car and pushing on the steering wheel won’t move you. That’s conservation of momentum. Having a car with no windows but with jets mounted in the back seats, that’s thrust, and that will move the car. Which is the EmDrive? I’d like to think it’s a new way of doing the latter. Ridiculing it can only hurt, and exploring it can only help, even if it helps us understand what did cause it.

It’s good to be a healthy critic, and to be ready to disbelieve things that fly in the face of established observations. But it’s also good to know when criticizing, and discouraging people from looking into something, is more shooting oneself in the foot than helping. Because at least in this case, I think we stand to gain a lot more from proving in practice why it doesn’t work so it can be put to rest, and even more to gain if we prove in practice why it does.

So maybe we should start an “open-source” campaign of micro-satellites. See what the innovative minds of inventors can do, to either prove, disprove, or improve what’s been reported.

    Ed Michalski · January 14, 2015 at 14:06

    Well said.

    IngoranceBeater · February 1, 2015 at 18:00

    “To answer your question, no, I wouldn’t accept that, but that also isn’t what they said. We can call what they said “technobabble,” and accuse them of making things up, but if you’re dealing with something you know you don’t entirely understand, but can see the results of, you need to call it something.”

    However, it’s not only the semantics that are in play here, but also the explanation they give to it. There IS NO way interaction with the virtual particles could offer the potential to transfer momentum. At least, not unless all we currently know about it is wrong.

    In that sense, it is no different than saying ‘The Spirit World’. After all, we may be wrong about the Spirit World too. Maybe the Spirit World DOES exist, and interacts with our real universe, after all? Can you disprove that? No. Both are, in effect, equally likely as an explanation of being the cause, if it’s just about giving a name to a presumed effect that can not be explained within our current framework.

    Thus why would you believe the former, but not the latter? Whether or not they would call it ‘The Spirit World’ should not, according to your own argument, change anything in regard to your acceptance of it, in that case.

ANap · November 11, 2014 at 19:50

Obviously this article proves beyond any shadow of a doubt that propellers do not work because boats don’t carry water as propellant.

    admin · November 11, 2014 at 20:41

    Hi ANap, thanks for your comment. Of course propellers are not reactionless thrusters, a boat’s propeller pushes mass behind it and the boat moves forward as the reaction,

    Now the Eagleworks team actually say in the introduction to their paper

    “Interaction with quantum vacuum virtual particles offers the potential to transfer momentum to space vehicles without this propellant mass fraction penalty, similar to the way a naval submarine interacts with the water which surrounds it.”

    This sentence suggests to me that they understand exactly how outrageous their claims are, and are trying to say that it is not reactionless but that there is reaction against action of “quantum vacuum virtual particles”. They do not seem to explain this anywhere else in the paper so it seems to me as as description of physical reality little better than science fiction technobabble.

    Imagine their paper had been published but instead the sentence quoted above read

    “Interaction with the Spirit World offers the potential to transfer momentum to space vehicles without this propellant mass fraction penalty, similar to the way a naval submarine interacts with the water which surrounds it.”

    Would you accept that?

glenn robinson · November 6, 2014 at 15:44

Has any qualified person looked at http://www.emdrive.com/yang-juan-paper-2012.pdf? This person seems to have a different theory, and a different test bench. Still, not tested in a vacuum.

ssmps · November 2, 2014 at 17:31

The language used to describe the backgrounds of the devices already tells you what the author’s conclusions are going to be. Shawyer’s ‘theoretical justification sounds frankly absurd’, salesman Fettta’s company ‘exploits’ his research into this ‘self-confessed nonsense’.

The real problem that is preventing us from learning whether there is really anything to these devices is this ridiculous focus on ‘challenging the laws of physics’. This instantly classifies these devices as fringe or pseudo-science.

If Shawyer’s theoretical explanation of the devices operation is completely wrong, that means nothing as proof of whether or not the device really works. Yet his theories have become the focus here. One side wants to challenge existing laws, the other to defend them.

Obviously, the results of the tests as described here aren’t worth much. A correct conclusion based on what I see here would be, ‘We don’t have any useful data as to whether the device works or not’. First, someone has to do some REAL testing to REALLY determine whether the device actually does what Shawyer claims or not. If it does, THEN start working on a determination of the mechanism – if it doesn’t, toss it on the trash heap.

How we should determine what is worth testing and what isn’t would probably be a more fruitful discussion. All we’ve got here is a discussion based on speculation from two different viewpoints. Don’t be so worried about the laws of physics, they can take care of themselves.

John O'Donnell · October 28, 2014 at 15:55

From an energy perspective – there’s a big paradox here (if reactionless propulsion is to be a reality)
1. Presumably, there will be some kind of engine/electricity generator to drive the cyclotron
2. It will have a non-zero efficiency (in terms of primary energy converted to spacecraft kinetic energy) Let’s assume 100% for now.
3. For an observer at rest –
– In accelerating from 0 to velocity v, the engine will need to generate 0.5*m*v*v joules.
– In accelerating from v to 2v, the engine will need to generate 3*0.5*m*v*v joules
– In accelerating from 1000v to 1001v, the engine will need to generate 2001*0.5*m*v*v joules.
4. However, for an observer in the “spaceship” there is no difference in accelerating from 0 to v and accelerating from v to 2v so the energy expended by the engine should be the same for both cases.
5. This paradox doesn’t arise in classical propulsion because the kinetic energies of the “spacecraft” and the expelled propellant all add up to the same value in all reference frames.

Al Gage · October 28, 2014 at 00:33

Shame on NASA for lending its reputation to the “junk science” report of a reactionless microwave thruster scheme. This isn’t science; it reeks of PR ballyhoo.

The “investigators” describe a good vacuum chamber and high vacuum system as part of their lab apparatus. Then they assert they couldn’t test their delicate micro-thrust gizmo in vacuum because the consumer-grade capacitors in the microwave power supply were not vacuum-rated. Given the obvious generous budget of the project, hermetically sealing the caps or even the entire power supply would have been a trivial expense. The whole proposition under test was whether or not the microwave gizmo actually produces reactionless thrust. That means the test is scientifically meaningless unless done in vacuum (even then, given the proximity of the vacuum chamber walls and the possibility of electromagnetic coupling with the massive vacuum chamber walls, the test would not have been definitive. NASA should demand its money back, and the taxpayers should demand some new NASA program managers. The reason given for the report’s ambiguity is about as scientifically plausible as St. Matthew’s account of the virgin birth. It’s hard to believe the same NASA that gave us Hubble, and Kepler, and operates robot rovers on Mars is now serving up this sort of transparent nonsense.

gt46l · October 23, 2014 at 15:53

How do magnets work? They push/pull without conservation of momentum. They are a loophole as well are they not? Its all just photons. What if the force being exerted by the em/cannae is a new kind of magnetic force(photon projector)? Still waiting for a real test of course, but why aren’t there more tests going on? I mean it doesn’t sound difficult/expensive to build. Nasa did this half-ass test on purpose to F with people.

    admin · October 24, 2014 at 10:39

    Hi,

    How do magnets work? They push/pull without conservation of momentum.

    That’s not correct. Why do you think that?

    What if the force being exerted by the em/cannae is a new kind of magnetic force(photon projector)?

    That’s not what its inventor says it is, and he should know! I also don’t think anyone has measured any such forces.

    Still waiting for a real test of course, but why aren’t there more tests going on? I mean it doesn’t sound difficult/expensive to build.

    It is so diffcult to actually do (the NASA Eagleworks people got very few results in their week of tests) and as I have tried to say the theories behind these devices are so jumbled, unclear and contradictory most scientists consider looking at testing them a waste of time.

John O'Donnell · October 20, 2014 at 14:03

Quote from article “•Most damning in my opinion, is the reported “thrust to power ratio” of 5.3 micro-Newtons per watt……1500 times greater (than what is possible from the inherent momentum of the generated radiation) ”

Why is this damning? Surely the whole point of the EMDrive/Cannae Drive is to develop an engine that can achieve more thrust than is possible by just generating microwaves and shining them out the back of the vehicle. In the EmDrive, doesn’t each photon contribute thrust many times over as it repeatedly bounces off each end of the cavity and experiences unequal deltas in momentum as it does so?

    admin · October 20, 2014 at 14:43

    Hi, thanks for your comment.

    My reasoning is that each microwave photon has a set energy E and momentum p (p=E/c) when it leaves the microwave emitter. E and p are both conserved. There is no passive process (such as the microwaves being forced into an oddly-shaped cavity) can increase these.

    In the EmDrive, doesn’t each photon contribute thrust many times over as it repeatedly bounces off each end of the cavity and experiences unequal deltas in momentum as it does so?

    This goes to the heart of why most scientists think the Cannae and EM Drive devices are absurd. Unbalanced forces in a closed system are not going to move the system. As I said in the article, a (incredibly lightweight) sealed box with a remote controlled helicopter inside is not going to fly around the room. Do you agree?

      John O'Donnell · October 20, 2014 at 15:17

      Admin, Thanks for responding.
      – Yes, I agree that a remote controlled helicopter inside a box is not going to fly around the room. Nothing we know of today could do that.
      – If the EmDrive does as advertised, it can make a sealed box fly around the room. I think we all agree on that.
      – I suspect you don’t really mean to say that, unbalanced forces in a closed system are not going to move the system. (I believe that unbalanced forces in a closed system will move the system.)
      – However, I believe (and I suspect this is what you mean to say) that it is not possible to have unbalanced forces in a closed system. In your excellent helicopter example, the lift from the helicopter exerted on the underside of the lid of the box will exactly equal the increased force due to downdraft on the floor of the box.
      I, like you, am extremely skeptical but……

Jerry Laskody · October 2, 2014 at 15:04

While I am a former propulsion engineer, I am no pooh poohing this so called “experimental result” because I don’t have enough information on this particular type of device .

However this information is very much like the elusive “second solution” in ejector theory. Many people have searched for this in ejector design and one person claimed to have achieved it in one experiment and it was not replicable. A careful analysis in that experiment indicated that very small errors in tare force for the experiment could indicate that the second solution was achieved when in fact it had not been. the fact that it could not be replicated was further evidence that it was most likely an experimental error. Since this article claims the experimental results were replicated that would give more credence to the claims. However, when I hear someone say” it works but we don’t understand why” I would advise them to understand why it works before they make a claim of success. These forces being “measured” are so small as to make specs of dust on the experimental apparatus significant.

I would urge caution about these experimental results until everything is well understood and this can be claimed as a breakthrough technology.

Rob · September 22, 2014 at 14:34

I don’t want to sound nit-picky, but you say the most damning thing is the suggestion of anything above 0.33nN/W.

This should actually be 3.3nN/W.

I completely agree that this is the most damning suggestion of any of these experiments. If they’ve truly achieved such efficiencies, then they should strap them to energy turbines and start producing energy.. They seem to ignore the fact that they’re claiming to be making energy.

In the conclusion, they say their next-generation drive can produce 100N/W.. A highschooler can easily understand what a ridiculous claim this is.

    admin · September 23, 2014 at 09:21

    Thanks for pointing that out, I’ve corrected the text accordingly.

Zanstel · August 26, 2014 at 12:08

Probably all theories here are flawned, but all devices are similar and all experiments show force.
Perhaps we should be more open minded and think that, perhaps, there is something we don’t understand. That the device works, it doesn’t mean that the explanation of the inventor is correct. But that the device works means that something tricky is happen. Perhaps an error or confusion that make the original purpone unusable. Perhaps not.

I think that the quantum explanation is the most near to real, if it works at all.

We know that “void” is really a false view of the “the things that don’t interact with us… normally”.
Something that don’t block photons is transparent. Something that don’t interact with matter and photons is “empty”.
But perhaps is not.

We know that virtual particles exists. They are not the same that real particles. In their limited life, it can interact with photons and matter very like as normal particles.
I suppose that it is that this authors call “virtual plasma”, something like “the sum of virtual particles that appear and interact with the photons”.

So, where a virtual particle absorbs a photon and gain momentum, where goes when the particle dissapear again?

Of course, we have construct mathematical models about these “virtual particles” and “quantum energy” that don’t allow interactions that have a net result different to zero, so it is supposed that it couldn’t exists a momentum transfer between the drive and the vacuum because that means that the properties of the vacuum changes in space and that “resurrect” the debate about something similar to “ether” that remains undetected.

But that’s is more likely to be a erroneous or incomplete model that something that “defies the newton law”.

If we are openminded about something that “exists” but normally don’t interact with us with a not zero result but, in special conditions, that result could exists, then this drive don’t seems impossible. They have found how to interact with something that even they don’t understand.

Of course, if newton law is correct (and no one discusse it), this “invisible thing” has momentum in some way.
If this works, we must found what is this and make a mathematical model of this interaction to exploit it.

    IngoranceBeater · February 1, 2015 at 17:32

    “Probably all theories here are flawned, but all devices are similar and all experiments show force.”

    All experiments were taken in an atmosphere too, not in a vacuum. The most common critique – and the most plausible explanation for the abnormality found, has to do with this factor. It’s strange therefore, such oversight has been made, when it’s an obvious factor that could interfere with the results measured.

    I see a lot of “it might be possible”…well, everything ‘might’ be possible. You can not scientifically disprove that the motion is not caused by the hand of god neither, for that matter. But that is not how science work; it’s not about proving an assertion that is unprovable, but proving one that IS possible to assert (or at least, observe). Science also follows Occams’ razor, so if you have various possibilities which would explain the minute forces detected after pouring lot’s of energy in there, you take the one with the least amount of assumptions.

    With our current knowledge of physics, this thrust can NOT be caused by ‘virtual particles’. This doesn’t change even if the author claims it doesn’t violate momentum and what not: his explanation for that is completely unfounded and, indeed, boils down to ‘the hand of god’. What he says about that, makes as much sense as saying it was caused by a toothfairy. There is NO such thing as a ‘virtual particle plasma’. And, contrary to what some claim, an eclectric field can NOT derive thrust out of interference with virtual particles.

    At least, not within our current framework and knowledge.

    Now, some are fast in pointing out ‘but maybe our knowledge isn’t complete’. Which is true. BUT, what some seem to ignore is, that it is FAR more unlikely that our totality of knowledge of physics and laws – which for more than a hundred year have been confirmed in every test as of yet – would suddenly turn out to be invalid, than it is to assume there has simply been made an error in the testing.

    Going for the most obvious cause, thus, would entail not inventing implausible and physics-breaking assumptions, but devising a more rigid testing, which would eliminate the far more likely causes of the result measured. One of the most prominent, as said, would be the atmosphere. A more precise measurement in a vacuum, with higher input (so the thrust would be significantly greater and can’t be attributed to ‘noise’) would be a necessity for that.

    Once that is done, we’ll talk further. If it still would give a positive result, the next step is an actual flight-test with a probe in space. Once that proves to work too, it’s time to rewrite our physics books. Not before.

    Until then, people should realise it is EXTREMELY unlikely that the drive works. It would, in fact, violate basic laws, whatever the author himself claims about it. “Extra-ordinary claims require extra-ordinary evidence.” The ‘evidence’ as of yet falls far short of being adequate, let alone it being extra-ordinary.

S Palms · August 18, 2014 at 18:10

While Shawyer’s explanation of the thrust of his engine is a clear violation of conservation laws, White’s explanation of why these drives work is not.

Virtual particles, which are predicated by quantum theory and are verified, are everywhere but come into existence and annihilate so the net effect is zero. However, virtual particles can be separated when they come into existence with an electric field (verified), so they don’t annihilate each other. Conservation laws are not violated since energy was added to the virtual particles separating them and making them real particles. This is how the black hole, energy from the black hole is added to the virtual particles, making them real, and separating them.

The explanation used in the Cannae engine is that particles that come into existence inside the cavity are immediately excited by the high energy microwaves, while the anti particles not in the field are not. The theory is that this adds energy to one of the two particles and separates the two preventing them from annihilating resulting in a net thrust.

As far as naming convention jabs, A plasma is defined as free electrons and/or positrons and free protons and/or anti-protons. It’s not a huge stretch to call particle anti-particles that appear and annihilate as a quantum virtual vacuum plasma despite the fact that the particles don’t act like a plasma. Even though that description has not been used before, it’s just being kinda a jerk to pretend that it doesn’t make sense. Besides, the virtual particles that become real by the addition of energy in the cavity could be excited by the microwaves to a high energy state which, if it consisted of free protons and electrons would be considered a true plasma consisting of particles that started out as virtual particles.

The null test rig was Fetta’s insistence that these slits were necessary. Other than that, the microwaves were still being switched on and off in the null rig and the thrust was still observed with microwaves on. All this demonstrated was that Fetta was wrong about the need for slits.

There’s no question that this needs to be tested in a vacuum to be verified because it could be an effect from heating air (I give this the highest probability if not a near certainty).

If virtual particles are being turned into real particles, then the horn should gain mass as it is powered and the other half of the particles outside the horn should be detectable.

The real questions: how many virtual particles are there in a given volume of space and how many of those could be excited to what energy level and what would the resultant thrust be? If it is separating virtual particles resulting in thrust, why does the wide end of the horn generate more virtual particles than the narrow end or the sides (if each surface of the cavity created the same number of virtual particles with the same energy levels, the effect would be zero thrust).

This is pretty fringe and probably will kill all credibility this post has, if it had any to begin with, but turning virtual particles into real particles could be creating space as in ‘space time’. This would also be easily measurable.

If there is ‘thrust’ from particle creation, the particles should be observable in the vacuum chamber and the test rig, if it is on a near friction-less rotating rig, should continuously accelerate, rotating faster and faster. If it is generating space at a fixed rate, it will rotate at a constant speed in a vacuum.

However, I’m pretty sure it won’t do anything in a vacuum.

    admin · August 19, 2014 at 07:47

    Hi, thanks for your comments.

    It’s not a huge stretch to call particle anti-particles that appear and annihilate as a quantum virtual vacuum plasma despite the fact that the particles don’t act like a plasma. Even though that description has not been used before, it’s just being kinda a jerk to pretend that it doesn’t make sense.

    The “quantum virtual vacuum plasma” description has been critised a lot (not just by me). I continue to think that using it was wrong, as you have said “It’s not a huge stretch to call particle anti-particles that appear and annihilate as a quantum virtual vacuum plasma despite the fact that the particles don’t act like a plasma

      S Palms · August 19, 2014 at 16:01

      Fair enough. Somebody ought to give it a name though since there are many virtual particles but they are theorizing that resonant cavities are targeting the virtual charged particles/anti particles in the quantum vacuum fluctuations?

      I retract the comment about a near friction less rotating rig not accelerating if it is generating ‘space’.

      If it is generating particles, the vacuum chamber pressure (assuming it works in a vacuum chamber) should rise as it operates.

      In the second paragraph of the original post it should read “This is how a black hole dissipates,…”

    Pomeziri · August 23, 2014 at 13:12

    In terms of why the thrust is coming from the narrow end, I think it has to do with the dielectric. The microwaves and the dielectric materials produce an electric field that provides energy to the virtual particles, temporarily making them real. There should also be a magnetic field generated which should chanel the flow of these particles.

Paul Piper · August 18, 2014 at 15:56

Look…it’ll work or it won’t. Testing will show this. If it does work, it doesn’t “break” the Law of Conservation of Momentum, it merely means our understanding of the Law is flawed; the equations will come in time.

I am a bit disturbed that so many scientist are happy to cross their arms and say “impossible.” That’s not how science works. Theorize, test, observe, report, conclude. If the Q-Drive works, great. It’ll open up the solar system in the way the airplane opened up the world. It’ll also provide a basis for investigating WHY it works, which when understood peels another layer off this amazing onion called the Universe.

Personally, I am hoping this gets me into space. I’d kind of been resigned to being born a little to early for it to be common for civilians, but if the Q-drive pans out, that may change before I shuffle of this mortal coil.

Fingers crossed (ok, not scientific, sue me).

    admin · August 19, 2014 at 06:39

    Hi Paul,

    What if researchers said they had tested a space drive device that violated the the rules of arithmetic? That is just as outrageous as conservation of momentum violation to physical scientists.

    Nevertheless, I’m sure I must have said in the article that I think it is worthwhile to repeat these tests more rigorously just in case.

    I do think the researchers should not have spent as much space describing their hypothetical Mars and Saturn missions, even if the results are valid, so far they have no basis to assume that the devices could be scaled up this way. Just as with the Eagleworks’ warp drive speculations, it seems pointless and unwise to promise so much based on so little.

Maciej Marosz · August 15, 2014 at 05:08

Right now I Poland I working on other very important Engine ( radial turbine )

http://www.spacetimeandtheuniverse.com/space-time-universe/7759-star-satellite-iii-newon-emdrive-future.html

(Dear Mr Marosz, Thank you for your comments, but it appears that you are using this page to promote your ideas rather than for discussion. This is not the venue for this and I do not intend to publish further off-topic comments- ADMIN)

Maciej Marosz · August 13, 2014 at 13:45

Joul / meter^3 = Newton*meter / meter^3 = Newton / meter^2 ( eureka pascal )

———————————————————————
mirror—–L—-Bulb——————-2L—————-mirror
——————————————————————–

Pipe is full vacuum and closed by mirrors

How many Joules / meter^3 will register mirror L and 2 L
what about if we will have 10 L …. 1000L ……

In 2012 I made in Poland
very important for physics test ( Michelson Morley Joul/meter^3 version )

http://3.bp.blogspot.com/-8wjLt-hPeu0/Utvr6OSc5II/AAAAAAAABkc/4lngY1EJC9o/s1600/tower+1.JPG

Astr – ASTRONOM

Astr1 ————bulb—————Astr2 >>> 30 km/s
……………………..p1

one sec later

……30km…..Astr1 ————bulb—————Astr2 >>> 30 km/s
……………………..p1

P1 it is stationary point in space ( ZERO ) !!! Energy = 3D ball respect to p1 point

How many joules / meter ^3 will register Asrt 1 and Astr 2

http://tesla4.blogspot.com

Maciej Marosz · August 13, 2014 at 13:38

EMdrive from POLAND 2014

long pipe is very important !!!

http://youtu.be/cSsTWRt0VBA

flux_capacitor · August 7, 2014 at 18:47

The test was not conducted in a vacuum, rather with the vacuum chamber “door closed but at ambient atmospheric pressure”. This was because the capacitors used in the test devices could not survive vacuum conditions, I presume this was a last minute discovery but the test programme went ahead regardless. Not performing the tests in a vacuum is a serious blow to the experiment’s credibility. The slightest air current could interfere with so slight a measurement. (UPDATE: I originally suggested that the electrical current fed to the drive device was generating heat which caused convectional air currents, moving the device on its pendulum. The paper seems to indicate thrust occurs instantly when the power is applied and drops immediately to zero when the power is cut off. That seems to suggest the device is not effected by self-generated convectional currents.)

May I suggest you a second update: NASA’s tapered cavity (aka EmDrive) tests were conducted with thick polyethylene dielectric discs put inside the cavity at the frustum’s small end. Without the PE dielectric discs inside the cavity, no thrust was observed (this information is written in NASA’s paper but apparently everybody missed it). Hence if heating or material evaporation of the cavity due to microwaves was acting on the ambient air and was a spurious cause of thrust, this spurious force would still be there with the cavity being filled with microwaves but without the PE discs inside. That is not the case.

    admin · August 8, 2014 at 09:38

    Hi, thank you, I have added this information to the article.

      Robert · August 12, 2014 at 16:42

      Good Morning.
      The debate goes round and round. Obviously the best course of action is to modify or update a version that can work in a vacuum and test the drive to prove or disprove the results. Heck, put a micro version in space and let it literally sink or fly (literally).

      I would love to see this or another technology work. I would also say if it works, it does NOT violate the physical laws of our universe. We are not defined by what we know so much as by what we don’t know. Would Wernher von Braun be amazed at a ion thruster?

      If the EmDrive works, would Einstein turn his back on it saying Impossible and turn his back on it? No, he would analyze and evaluate it properly, and would be glad to prove or disprove the devices properties.

      It might just be someone found an approach that allows a drive to function differently than what we normally see. Breaking into a new paradigm is always hard. Proving it works, or does not work is only a small testing series.

      Lets embrace the chance of a new concept or idea being possible, and not ride it into the trash without a fair evaluation.

      Where we go from here is so important. Finding the path forward to new developments is always hard. Lets give these developers a chance to prove themselves without the “I told you so’s” that would limit or block the possibilities towards advances.

      These developments towards new technology and new drive propulsion systems should be encouraged for the efforts to get us out of this gravity well and into a new realm of exploration and expansionism.

    Juno · September 28, 2014 at 16:00

    Or, the PE disks were absorbing energy and converting it to heat.

flux_capacitor · August 7, 2014 at 18:14

Another inventor, Guido P. Fetta has suggested a similar device to the EmDrive that he has called the Cannae drive (confusingly also known as the quantum vacuum plasma thruster or Q-drive)

No it’s not.

Fetta’s Cannae drive is an asymmetric RF resonant cavity filled with microwaves, and is very similar to but flatter than Shawyer’s tapered cavity aka EmDrive. The Cannae drive used to be known as the Q-drive. Picture of a Cannae drive (NASA’s 2013 version).
The Quantum Vacuum Plasma Thruster (QVPT) also called Q-thruster (maybe the confusion comes from that last names) is a different beast. It was invented by NASA engineer Harold “Sonny” White, as a copy of Jim Woodward’s Mach Effect Thruster (MET) 2006 test article, but intended to be used with DC currents. The QVPT is made of capacitors in a torus with a magnetic coil around, where E and B fields are crossed. It has nothing to do with a microwave cavity. You have a picture of a QVPT on wikipedia. The QVPT presumes the existence of a “virtual plasma” due to quantum vacuum fluctuations (QVF) that could be propelled by the Lorentz force due to crossed E×B fields (magnetohydrodynamics). This is White’s unproven conjecture.

The Cannae drive seems to work without any theory to explain its thrust; whereas the QVPT is the opposite: it doesn’t work whereas it was built to experimentally demonstrate White’s QVF theory, and failed (unlike Woodward’s MET that it originated from, which successfully ran on AC currents and is theoretically based on Mach’s principle).

Vincent · August 7, 2014 at 13:16

It seems a bit premature to claim that this is a hoax, even is it seems very likely.

Science is about empirically testable results and so far there are only two and both have reproduced the results of the designer. The only way to counter empirical evidence is with better empirical evidence.

    admin · August 8, 2014 at 06:43

    Thanks for your comment, I’d just like to clarify that I do not believe this is a hoax. I am sure that the experimenters are completely sincere.

    James · January 4, 2015 at 20:43

    Just to say multiple tests have been done of Shawyer’s EM device… http://emdrive.com/faq.html also see the latest info on the site

Kiesch · August 7, 2014 at 10:34

Obviously – if NASA really believes this, a good test would be bringing such a device into space and testing it. But since it seemingly doesn’t work in Vacuum (oh how convenient for the inventor) that doesn’t seem to be a problem.

Anyway: If it’s complex enough to just explain it away, give it a try. And if it works, let theorists discuss about it for some years, until they come up with how the device obeys Newtons law (which I find pretty likely).
But sadly the more probable thing is, that the device just won’t work. Anyway – I’m open to surprises.

P.S OT: Physicists are not very likely to believe such devices, simply because there are so many inventors of such or similar devices (typically these guys don’t have a background in physics or even engineering), that are just not working as advertised (either the creator just oversaw some incoming force or interaction or actually mistaking a measurement error for a real effect). The most annoying is, when these guys are not even willing to let there devices being testet under a scientific method (which for me just shows, that the “inventor” is fully aware of his nonfunctioning device and just wants to make money with it anyway).

P.P.S: It’s really odd, that the testing staff at NASA didn’t find it odd that the “nonfunctional” device also produced thrust….

Rick Bailey · August 6, 2014 at 13:01

A couple of possible typos:

I think in the fourth paragraph you meant to say “However, rockets are clumsy and in-efficient” rather than “rockets are clumsy and efficient”.

And in your reasons to be skeptical, I think you meant to say “It is extremely odd that a device designed by its creator to be inoperable…” rather than “It is extremely odd that a device designed by its creator to be operable…”

Otherwise, thanks for a very interesting article.

    admin · August 6, 2014 at 13:02

    Thank you, I’ll get the typos fixed now.

David Byrden · August 6, 2014 at 09:09

The theory of the Emdrive, as presented in Roger Shawyer’s technical paper version 9.4 (still on the Emdrive website as of today) is deficient.
Forces on the front and rear walls are taken into account; forces on the slanted sidewalls are ignored. The results are therefore invalid. Consequently we have no reason to expect that an Emdrive will work.

This deficiency has long ago been brought to Mr. Shawyer’s attention, according to numerous sources. As far as I am aware, he has responded only by assuring us that sidewall forces were “minimised”. If he knows them, I would expect him to publish them.

Richard · August 5, 2014 at 15:33

The British “inventor” claims it will be possible to build a superconducting Em-drive, capable
of accelerating a 3-tonne mass at 1G with 1kw of input, pans out like this:

P = E / t

E = P x t = 1/2mv^2

So in the first second of time (t=1), this of 3000 kg would be

accelerated to 9.8 meters per second, through the expenditure

of 1000 joules (1 watt = 1 joule per second, 1 joule = 1 kg-m^2/sec^2)

At t=1

Energy “in” is 1000 joules

Energy of the object = 1/2 mv^2 = 1/2 x 3000 x 9.8^2 = 144060 joules

Basic physics would be severely “violated”, it would seem, so at least

one inventor is either nuts, or sucking an energy multiplier of 144 out of an

alternate universe … not by a little, but in gobs. And I wonder why

science reporters still don’t know basic physics and can’t do simple math?

What do you think?

(Material speculating on the inventor’s motives removed. I am sorry but we cannot publish this material – ADMIN)

    admin · August 6, 2014 at 07:46

    Yes, you make a good point. I agree that the situation you describe does violate conservation of energy.

    To be fair Shawyer has sort of addressed this, saying “because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.” (Quoted in the EmDrive FAQ)

    This is a puzzling statement as it sounds more like it’s describing an anti-gravity device than a thruster. It does too beg the question of what Shawyer believes his device will do in a gravity free environment, to obey the law of conservation of energy, does an EmDrive spaceship need “auxiliary propulsion” too?

    Jerry · September 28, 2014 at 16:58

    I think the energy multiplier issue is indeed confusing to those who do not understand how resonant cavities work. But the concept is much like pushing a child on a swing set. Imagine how high a small child can throw another child without a swing.. not very high… but with a swing that stores the energy from each push, and with a push carefully timed to amplify the energy, every a seven year old can lift a child on a swing several meters! The key is the ratio of the energy added vs the energy dissipated, known as the Q-factor.

    http://en.wikipedia.org/wiki/Q_factor

    In much the same way, a wine glass that is stimulated with a damp finger on the rim can generate a sound that gets louder and louder the more one feeds energy onto the system.

    A resonant cavity works in much the same way with EM waves, with Q-factors that typically operate in the range of 5000-15000 or more. The power is fed through and antenna and dissipated in the walls of the cavity. At resonant modes, standing waves increase in amplitude, creating very strong fields that are much higher than what is though to be possible from the power being fed without resonance.

    So the next time one looks at these numbers and say its impossible, remember the story of the child on the swing set, and make a bet that even a seven year old can lift a kid three times his own height 🙂

      admin · September 29, 2014 at 09:14

      Hi Jerry, thank you for your comment, do you agree though that no resonant system can put out more energy than is put into it?

Neal J. King · August 5, 2014 at 06:53

Colin:

I would take minor issue with you: It is indeed a free-energy device:
– On the basis of microwaves that never escape the box, the ship accelerates over time to finite velocity, so that means it has perceptible kinetic energy. This can be turned into work. In the meantime, the microwave energy has not escaped, so you have gotten this KE for nothing. This means: violation of conservation of momentum, energy and the 2nd law of thermodynamics, all in one device. Isn’t relativity wonderful.
– If instead one claims that the microwave energy is really being turned into KE, then we’re only violating conservation of momentum and the 2nd law.

    admin · August 5, 2014 at 07:51

    I have encountered a couple of folk who believe the device is some kind of generator but that’s not what the researchers are claiming at all. Judging by the incredible power to thrust ratio (28W to 50 micro Newtons) it is an impressive disippator rather than generator.

    I think even Shawyer believes the microwaves are eventually absorbed (warming the structure of the box) so power must be applied to maintain the acceleration. So it appears not to violate the laws of thermodynamics.

      Dr. Jonas Moses · September 21, 2014 at 21:18

      “Admin,” (presumably, Colin), as a longtime researcher, scientist and innovator, sometime biomedical engineer and medical clinician, I would like to point out that it really does not matter that it is “not what the researchers are claiming at all…” Real innovation exists in a vacuum (pun unintended): that is to say it is irrelevant whether or not the intended and/or claimed uses of an invention are the ones ultimately proven (shown) to be real. ANY innovation is just that: an innovation…something that promotes the science or other field of endeavor.

      Admin, you seem to prone to splitting hairs, in how you articulate the facts of this discussion. I will do you the kindness of inferring that you are merely seeking to protect your readers from taking unreasonable leaps to scientifically unsustainable conclusions. However improbable or implausible these devices may feel to you, I am going to err on the opposite side, and suggest these claims and experimental results are…possible.

      I would remind you that there was, once, an eight hundred year period of recent history (relative to our earliest recorded history) when it was not only asserted that the Earth is flat, but also resided at “the center of everything.” Not only was this a certainty — rendering any other theories wholly impossible — but to state otherwise was “blasphemy,” of which proposing alternative views could (and did) result in death.

      By choosing to approach this intriguing subject with tongue planted firmly in cheek, I think you may run the risk of prejudicing your clever and innovative (but, perhaps somewhat fearful of ridicule) audience. You may, thus, albeit inadvertently, be pushing them away from further intellectual explorations, of their own! Meanwhile, I shall await the verdict of future experimentation, from those who are less inclined to sit armchair-lengths away from the action.

      With utmost respect,

      Dr. Jonas Moses

Barry Nicholson · August 5, 2014 at 04:57

Since photons can provide a reactive force, but can also be easily converted into heat by absorption, couldn’t you end up with a net force? The emission source would move in the opposite direction to emitted photons which are then absorbed and converted to heat, rather than a pressure, resulting in a net force.

    admin · August 5, 2014 at 07:37

    I’m not sure if we are thinking the same thing, but I am suspicious that the device tested is warming up and in turn heating the air around it. The warm air rises creating a current which circulates around the chamber, moving the device on its pendulum. That is my theory and why I will take this a lot more seriously if they can repeat this in a vacuum.

      --- · August 6, 2014 at 23:53

      could it also be an ionic wind effect? metal surfaces becoming charged, charging the air and causing it to move? like “Lifters” or “ionocraft”.

        admin · August 7, 2014 at 06:51

        I don’t think that is very likely as the NASA test articles are compact and dense compared to ionocraft. Repeating the tests in a vacuum would rule this out.

      Jarea · January 20, 2015 at 20:37

      To discover if what you say about the air getting hot and lifting the box there is a very easy experiment. Do the experiment without air, in the vacuum. That should be easy!. I think he has already done this to discard that. I don´t know but If he hasnt done this yet after years, he is too stupid. NASA should also do that.

        Jarea · January 20, 2015 at 20:49

        From
        http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive

        3. They didn’t do it in a vacuum, so how do we know the result is valid in space?

        While the original abstract says that tests were run “within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure”, the full report describes tests in which turbo vacuum pumps were used to evacuate the test chamber to a pressure of five millionths of a Torr, or about a hundred-millionth of normal atmospheric pressure.

          admin · January 20, 2015 at 21:59

          Dear Jarea, thanks for your comments. It seems to me that there is confusion over the issue of whether or not the devices were tested in a vacuum. To be honest this is mainly the fault of the authors of Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum (the full report, not the abstract) as it fails to spell out some critical details. Let me try to show you why I think this.

          In section II. Thrust Measurement System (Torsion Pendulum) they describe their test equipment including a very detailed description of the capabilities of the vacuum chamber. This includes the words

          “During test run data takes at vacuum, the turbo pumps continue to run to maintain the hard vacuum environment. The high-frequency vibrations from the turbo pump have no noticeable effect on the testing seismic environment.”

          These words really do make it sound as though tests runs were performed in a vaccuum.

          Sections III and IV discuss the results. Nowhere does the report say the tests were conducted in a vacuum! Surely it would very important to state this as it would make the results less ambiguous.

          The ultimate proof that the tests were not conducted in a vacuum is in section VI. Summary and Forward Work. This contains the sentence

          “Vacuum compatible RF amplifiers with power ranges of up to 125 watts will allow testing at vacuum conditions which was not possible using our current RF amplifiers due to the presence of electrolytic capacitors.” (my bolding)

          The author of the Wired piece is very sure that the tests were performed in a vacuum, I cannot see how he can read the report and believe they were.

          I would welcome any input from anyone who can clarify this.

      Shawn Kearney · February 17, 2015 at 05:30

      The article is confusing about whether it had been tested in a vacuum on it’s first trial. Eagleworks did share this link (which I mentioned elsewhere):

      http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive

      It states that:

      “While the original abstract says that tests were run “within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure”, the full report describes tests in which turbo vacuum pumps were used to evacuate the test chamber to a pressure of five millionths of a Torr, or about a hundred-millionth of normal atmospheric pressure.”

      Maybe it was a typo?

      More recent tests were done in hard vacuum, but were met with technical difficulties with their amplifiers – still, managed to produce thrust:

      http://nextbigfuture.com/2015/02/update-on-emdrive-work-at-nasa.html

        admin · February 17, 2015 at 08:14

        I was pretty clear that the original tests were not conducted in a vacuum, despite what a lot a lot of other folks were saying. I go through this in detail in my response to Jarea on January 20, 2015. I cannot understand how anyone can read Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum and not see that the tests were not done in a vacuum.

        I have updated the article to reflect the reports that the tests have been repeated in a vacuum. If this is is correct it is very exciting.

          Shawn Kearney · February 17, 2015 at 21:20

          That Wired article was endorsed by Eagleworks directly. So i don’t know, it just seems very confusing.

          (fyi, I didn’t see this reply when I posted)

Denra · August 4, 2014 at 21:03

Just because science says something is impossible, doesn’t make it so. Science has been proved wrong before. Take the time to check the facts, Perhaps for those things where science has been wrong in the past. To say a thing is impossible, is merely a hypothesis. It does not become theory until proven to be such, and even then, is subject to change as time goes by. Science is not nd never has been infallible.

    admin · August 5, 2014 at 07:23

    I completely agree. But overturning conservation of momentum would be a truly astonishing revolution in science, and the the results of this experiment are so premature and insubstantial we’re nowhere near that stage yet.

      Zack · August 21, 2014 at 20:58

      It should be unsurprising that two different proponents of similar novel devices would have different hypotheses of how their own device works. It should also be unsurprising that independent researchers arrive at yet a third hypothesis for the mechanism of operation of these “canned magnetron” devices. An interaction with the “quantum vacuum virtual plasma” (an attempt by the study authors to provide a generic term for the non-intuitive source of, say, the Casimir effect) does not necessarily invoke new physics. Furthermore, it is easy to imagine that a “resonant cavity” where-in the nodes and anti-nodes of the standing RF wave within are arranged in an asymmetrical way…

      But without trying to blindly dive into armchair musings of how these devices may operate, instead I’ll make my actual point. It may be possible for a “reactionless drive” to function by side-stepping the law of conservation of momentum, not breaking it. The nearest analogy is the way by which the theoretical Alcubierre “warp drive” side-steps the universal speed limit. The key here is side-stepping, as opposed to rule rewriting. Special and general relativity did not require the rules to be rewritten, but only appended (albeit in very serious ways).

      As we progress to our collective future, major breakthroughs in technology will continue to appear to break some serious laws of physics; the legitimacy of research into LENR, for example, continues to be hampered by a rather dogmatic refusal to accept that the Coulomb barrier of electrostatic repulsion of nuclei can be exceeded without million degree temperatures. Is not quantum tunneling a way of sidestepping this requirement? Again, my emphasis lies in that the laws of physics will never be fundamentally rewritten; instead, like a book of law, it will only grow in depth, breadth, complexity, and according to Godel, loopholes.

      The greatest mistake science can make is to think there is an glorious, elegant, and unchanging endpoint of understanding.

        tom · June 25, 2015 at 01:29

        yep ,zacktly

          tom · June 25, 2015 at 01:32

          if we can learn to interact w the virt. plasma,,,, who knows how far it will go,, the great mystery,, thats where its al leading to

      Robert · September 29, 2014 at 15:41

      You assume they are claiming the law of momentum conservation is broken which it is not as they state. It is just that perhaps our understanding is incomplete.

      The NASA test results are the third test results if this phenomenon and should be taken seriously instead of just scoffed off.

        Pablo · February 24, 2016 at 07:57

        I’ve wondered about that. Relativistic conservation of momentum must include the energy/mass equivalence. If mass transforms to energy, where does momentum go? Where does gravity go?

      James · January 4, 2015 at 20:35

      EM drive does not supposedly break the laws of physics as Mr Shawyer describes on his website- http://emdrive.com/faq.html

        admin · January 5, 2015 at 09:09

        Hi James, the problem is Shawyer’s reasoning is not accepted by the vast majority of physicists. He says he has invented a box which moves without emitting anything, straight away this violates Newton’s laws.

          Guillermo · January 17, 2015 at 14:02

          Common, we all know Newton’s laws are approximate. The conservation of momentum seems to work even on the standard model, however its interpretation is very different, and interactions with the vacuum particles may not be impossible. Instead of dismissing it on the grounds of “it violates Newton’s laws” physicists should take the opportunity of discovering some interesting new physics. I mean it would take a ridicule fraction of the cost of the LHC to perform these experiments. It is true we should not be spending as much on it, because we know the grounds the LHC explores are unknown, so what we find will always be at least a bit useful (or maybe a lot). But for their cost and expected outcomes weighted by significance, I think these are also worthy experiments to do.

          Jacob · March 25, 2015 at 21:15

          Just to expand some on why his explanation does not seem to make sense, In his tapered waveguide example he is ignoring the way photons will be reflected off of the tapered sides of the waveguide, because of the angle involved there will be a change in momentum of the photons in the axial direction. Once this change in momentum is accounted for (in the non relativistic case at least) there is no longer a difference in the momentum (and thus force) being applied in the two directions.

          I haven’t closely checked calculations in later parts of his explanation, but he appears to continue to ignore important angular effects throughout. Assuming later that all photons will hit the ends of the waveguide straight on (even though his own pictures clearly show that is not the case) and thus overestimating the amount of force being applied to them.

          I don’t want to start an argument, and I do agree that this is something that should be investigated further (and I am sure it will be) but I thought I would offer up some more specific problems with his explanation than the admin did in a hope to better explain why physicists are not buying into it. It isn’t just that it is violating will established physical laws, It is also that there are clear oversights in his derivation that invalidate his conclusions.

      Lawesty · January 22, 2015 at 14:32

      http://www.emdrive.com/IAC13paper17254.v2.pdf here is the scientific paper.

        Maxim Sukharev · March 17, 2015 at 23:57

        Sadly, this is NOT a scientific paper as it wasn’t published in any peer-reviewed journal. Writing something using Mathtype and putting it on your website doesn’t make it scientific 🙂

      Gyro · August 31, 2015 at 07:23

      Your statement “But overturning conservation of momentum would be a truly astonishing revolution in science” should not use the conditional but the present.
      The physicists James Woodward, Ph.D., and Heidi Fearn, Ph.D. have shown that the General Relativity Theory of Einstein applied to our Universe flat geometric status ( as demonstrated by WMAP and Planck space measurement of the Cosmic Radiation Background) fully endorse the Mach Principle and so that in some situation the conservation of momentum is not mandatory at local level but need only to be endorsed at the whole universe level.
      This prediction is completely out of the Newton’s conception of Space and needs to be understood the tool of General Relativity and the philosophical vision of Ernst Mach on the origin of Inertia.

      The possibility of a thrust without propelant mass expulsion is so fully theoreticaly possible according the today known physics.
      Moreover many evidences seem to show the experimental confirmation of this theoretical prediction (delicate measurements with spurious sources of error as usual in physics).

      References :

      – Making Starships and Stargates : The Science of Interstellar Transport and Absurdly Benign Wormholes; Author : James Woodward; Editor : Springer; 297 pages.

      http://boingboing.net/2014/11/24/the-quest-for-a-reactionless-s.html

      itsme · November 6, 2015 at 05:51

      Can we take hope in the possibility that this is a quantum level effect and therefore perhaps subject to a different set of natural laws? I know there is even to this day, a great contradiction between the standard model and quantum mechanics; although I confess, I am not sophisticated enough in my understanding to describe those conflicts.

    JerryG · January 8, 2015 at 21:01

    Agree, but what science has proven with experiments is law. Their big problem lies within the framework that cannot be both explained and proven. This is not small scale either. Case in point levitation, teleportation, and matter embedded within other matter.

    We are still a long way from getting everything right today.

    Shawn Kearney · February 16, 2015 at 09:23

    more important is that simply because it looks like it’s violating the conservation of energy does not mean that it actually is. For people 500 years ago, a car would look like it propels itself, as if by magic.

    Without a full explanation about how energy is stored in liquid fuel and then burned to produce torque, this would be a perfectly rational explanation: that the car propels itself without external energy.

    Just because we cannot see what is causing the thrust, or understand the mechanism of how electrical energy is being converted into mechanical thrust does not mean that it’s fundamentally “magical” i.e. violating known laws of physics.

    I personally do not think it’s violating the laws of conservation. It might look that way from the outside, however, that does not mean that it actually is.

      admin · February 16, 2015 at 10:52

      Dear Shawn, thanks for your comments. What do imagine would happen if one of these devices was sealed inside a “perfect” box (nothing can escape it, no gases, no photons, no known subatomic particle) and powered up. Does the box move or not?

        Shawn Kearney · February 17, 2015 at 05:09

        I’m inclined to agree that no movement would happen. I don’t think that fundamental physics are being violated, only that we cannot detect or understand the reaction.

        If it does produce thrust then it’s not an “impossible drive”, otherwise it wouldn’t do anything. There is a rational explanation here, and I doubt very much that the rational explanation is that the laws of physics as we know it are wrong.

        It could be EM alone through some kind of resonant phenomenon that we don’t yet understand. If you ask David Pares he’d probably tell you that it’s a warp drive, since it’s not that far off from his Bermuda triangle-based theory. Maybe God in somehow involved. Again, it could be anything – but what is most likely is some kind of simple reaction that can be explained through known mechanics, but one we cannot detect. At least the NASA explanation provides that much.

    martinc · July 27, 2015 at 21:28

    Hi, Nasa detected a warping of space/time when they fired a laser through a working EM Drive. Not ‘peer reviewed’ or anything, but they discovered a warping
    [This is published fact so no-one can argue they didn’t detect this!]

    So what if it is this that generates the force detected and not quantum plasma or the inventors own theory?
    If it was warping ..then Newtons law is not broken, and nor is Einsteins.
    By incorporating the theoretical models of the Alcubierre warp field..(which is what NASA found)

    So this solves the problem of the physics,
    how come no-one is talking about this and made the obvious connection between the thrust observed and the warping observed?!

    Presumably how it works is space/time is funelled into the warp field and this acts on the space/time within the body of the engine and the body itself moving it toward the warp. In effect it isn’t reactionless at all, it’s just that the propellant is space/time.
    i don’t need to tell you how amazing this would be or go over some of the other really incredible pieces of luck we would have if this was true for getting to FTL travel (i.e. apparent no need for dark matter or ultra high power levels)…

    Assume for a moment the EM Drive works and it does it by a warp of space/time… anyone care to riff on how this is actually generating the force? is the warp filling up the body of the engine or are there multiple tiny warp bubbles?

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