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NASA Space Science Technology

Final NASA Eagleworks Paper Confirms Promising EM Drive Results (hacked.com) 477

An anonymous reader quotes a report from Hacked: Earlier this month Hacked reported that a draft version of the much expected EmDrive paper by the NASA Eagleworks team, had been leaked. Now, the final version of the paper has been published. The NASA Eagleworks paper, titled "Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum," has been published online as an open access "article in advance" in the American Institute of Aeronautics and Astronautics (AIAA)'s Journal of Propulsion and Power, a prestigious peer-reviewed journal. The paper will appear in the December print issue of the journal. The final version of the paper is very similar to the leaked draft. In particular, the NASA scientists confirm the promising experimental results: "Thrust data from forward, reverse, and null suggested that the system was consistently performing at 1.2 +/- 0.1 mNkW, which was very close to the average impulsive performance measured in air. A number of error sources were considered and discussed." The scientists add that, though the test campaign was not focused on optimizing performance and was more an exercise in existence proof, it is still useful to put the observed thrust-to-power figure of 1.2 mN/kW in context. "[For] missions with very large delta-v requirements, having a propellant consumption rate of zero could offset the higher power requirements. The 1.2 mN/kW performance parameter is over two orders of magnitude higher than other forms of 'zero propellant' propulsion, such as light sails, laser propulsion, and photon rockets having thrust-to-power levels in the 3.33--6.67 uN/kW (or 0.0033--0.0067 mN/kW) range." In other words, a modest thrust without having to carry fuel can be better, especially for long-distance space missions, than a higher thrust at the cost of having to carry bulky and heavy propellant reserves, and the EmDrive performs much better than the other "zero propellant" propulsion systems studied to date.
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Final NASA Eagleworks Paper Confirms Promising EM Drive Results

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  • by tietokone-olmi ( 26595 ) on Saturday November 19, 2016 @02:15AM (#53320565)

    What's the usual format of an EM drive? Does it go on a satellite for maintaining orbit instead of a chemical thruster that'll one day run out of fuel? On an interplanetary probe for long-term acceleration, like solar sails might? How big should it be for useful propulsion, and what levels of power does it require -- given that heat dissipation is a perpetual issue for small spacecraft?

    • by sheramil ( 921315 ) on Saturday November 19, 2016 @03:13AM (#53320657)

      What's the usual format of an EM drive?

      Large arrays of them go on the back of our Terran Battleship to propel them out into the darkness as they bring the Light of Mankind to a savage and ignorant galaxy. Until we find someone smarter than us.

      • Large arrays of them go on the back of our Terran Battleship to propel them out into the darkness as they bring the Light of Mankind to a savage and ignorant galaxy. Until the robots running the ship rise up against their masters and return to destroy us all

        There, fixed it for you

    • by Anonymous Coward on Saturday November 19, 2016 @03:20AM (#53320673)

      The most implication of experimentally confirming these observations would be for our fundamental physical models [wikipedia.org]. Nobody can really say what it means, but it is potentially as important as the discovery of spectral lines [wikipedia.org], which was instrumental for the development of quantum theory.

      As with most discoveries in fundamental physics, the actual applications are often unpredictable and rarely match the initial expectations. If anyone tells you they know, they are talking out of their asses.

      • Re: (Score:3, Insightful)

        by Spazmania ( 174582 )

        You vastly underestimate the situation. The EM drive could be the Michelson-Morley experiments of the 21st century. If you don't recognize that, those are the series of experiments whose "inexplicable" data led to Einstein's discovery of relativity.

    • by OpenSourced ( 323149 ) on Saturday November 19, 2016 @04:21AM (#53320805) Journal

      Are you serious? If the EM drive works we are at the gates of a major revolution in Physics (as in 'our understanding of Physics'). First we should have to understand how it works, tinker with it till the smallest-lightest-efficientest designs emerge. In parallel, other people would be trying to determine WHY it works. That's a much bigger task, that requires a rewriting of most Physic's textbooks. When we have a new theory that explains the EM drive, then probably still better drives can be designed, perhaps using other kinds of radiation.

      What I'm driving at, is that discussing how possibly adequate or inadequate this EM drive is to space travel is like discussing the usefulness of electricity when good old Thales started rubbing amber pieces against animal skins.

      • >Are you serious?

        Yes. By examining its practicability in the current format, we can guess at how much improvement is still on the cards, or remain in the deck, for various aspects of the technology. Changes to the fundamental sciences are so impredictable as to not consider; so I'm assuming they're precious to basically everyone for exactly the reason that we now have nuclear power and what-not despite at first only having extremely huge bombs.

        • by Immerman ( 2627577 ) on Saturday November 19, 2016 @10:57AM (#53321711)

          Umm, you realize we needed to make nuclear power plants *before* we could make the bombs, right? Granted they were designed specifically to enrich the natural fissiles into weapons-grade isotopes, but the reactors still came first.

          And no, looking at the current state of a technology based on physics that we don't yet understand in no way helps us understand how much improvement that technology may undergo. At best it gives us a glimpse at what it might enable.

          In that context though, the best initial application is likely to be deep space probes. Satellite maintenance might get included as well, but that's more a convenience than an enabling technology - there's already orbital refueling vehicles under development. Deep space though - that's where constant low thrust acceleration pays off big time.

          From what I can find, current RTGs for space applications top out at about 5W/kg. Assuming a 1kW RTG is half the total mass of the probe, that gives us a 400kg probe with 1.2mN of thrust using the current unoptimized EM drive tested. That translates to 3um/s^2 of constant acceleration. You're not going see much change right away. Starting from rest, in one minute it will travel a grand total of 5.4mm. But acceleration adds up:
          Displacement as a function of time:
          1day: 11km. 1 week:550km 1month:10,000km 1 year:1.5Mkm (yay, 0.5% of the way to Mars!) 10 years: 150Mkm (Wait, we're still not to Mars?). 100 years: 1.5Bkm (3x the distance to Pluto). 5200 years: ~4.2 light years(we've reached Proxima Centauri!)

          So yeah, with current technology it's not actually much good for deep space probes, and I haven't even factored in the losses of climbing out of the sun's gravitational well. If you're operating close enough to the sun to use solar though you can up your power to 300W/kg (near Earth orbit), and assuming the same 50/50 power to payload ratio that will get you ~60x the thrust (and thus 60x the distance per unit time). Then the numbers look a bit better: You might get most of the way to Mars in a single year for example. And more importantly be able to turn around and repeat the journey indefinitely.

          So I suppose inner-system scouting probes and perhaps interplanetary cargo transportation could be early applications. And if optimizations could yield a 10-fold improvement in engine thrust/W, well then things start getting really interesting. Travel to and from Mars in a month, with no need for refueling? That's the stuff science fiction is made of.

      • by Lumpy ( 12016 ) on Saturday November 19, 2016 @07:29AM (#53321147) Homepage

        It's very simple, instead of being inefficient like a regular rocket engine and moves the rocket in space, it simply allows the rocket to be stationary and it moves the universe.

      • There is no rewrite of any single text book necessary.
        There is a small chapter added to quantum mechanics, that's it.

    • The current test article appears to be the size of a 10 gallon bucket. With all associated hardware to drive the chamber, all hardware could fit neatly inside the volume of a 50 gal barrel.

      Minus the power supply, this is able to supply the stated specific impulse of the article.

      The mass of the test article and associated hardware is not given, and above estimations for volume come from photos of the test apparatus.

    • by Black Parrot ( 19622 ) on Saturday November 19, 2016 @06:07AM (#53320987)

      What's the usual format of an EM drive?

      NTFS.

    • by Lumpy ( 12016 )

      Yes and Yes. and if we find a way to make a LOT of electricity, 10,000,000Kw of power into one will produce 1000N of thrust assuming a linear scale up.

            What is needed is to see if the drive will actually scale up.

      The other thing is, now that it is proven to actually work, refinements can be made to the whole design to increase efficiency that may give us even more thrust per KW of electrical energy.

    • "The 1.2mN/kW1.2mN/kW performance parameter is over two orders of magnitude higher than other forms of “zero-propellant” propulsion, such as light sails,"

      I have a question: What the smurf does this mean? Seriously?

      Are we talking about a ground-based laser pushing it? In which case, the idiocy of comparing a system that you have to lift into space, in which every gram is critical, versus something here that can be hooked up to the power grid, is beyond belief.

      Are we talking about a solar sail

      • that should be ±6 micro Newton, apparently /. doesn't display the (micro) symbol consistently.
      • "The 1.2mN/kW1.2mN/kW performance parameter is over two orders of magnitude higher than other forms of “zero-propellant” propulsion, such as light sails,"
        I have a question: What the smurf does this mean?

        They're talking about technologies that use no reaction mass, not that use no fuel.

    • What's the usual format of an EM drive?

      Half-assembled in a shed out back, because the fucking thing is total snake oil.

  • What would a spacecraft operating an EM drive at peak efficiency look like? Say, a Star Wars Star Destroyer going from low-earth to geocentric orbit in 'reasonable' time (30 minutes). Would the relative size of EM engine to Star Destroyer body be 1:10? Or 100:1?

    • This is such a great question Mr. Chauhan. I am sure it would be really easy to answer for anyone who has dabbled in those kinds of equations. Or here is another permutation of the same question: Imagine the two Voyager craft that were launched in the 70's. If they were equipped with EM drive with approximately 250 watts of continuous power how much further away would they be now and how much faster would they be travelling?
    • > Say, a Star Wars Star Destroyer going from low-earth to geocentric orbit in 'reasonable' time (30 minutes). Would the relative size of EM engine to Star Destroyer body be 1:10? Or 100:1?

      Without actually doing the math, the drive would be at least millions to trillions of times bigger than the ship. There is so little thrust that it's extremely difficult to tell if there is any thrust.

    • What would a spacecraft operating an EM drive at peak efficiency look like?

      Stationary.

  • vaporising metal? (Score:5, Interesting)

    by Anonymous Coward on Saturday November 19, 2016 @03:25AM (#53320681)

    They say that they have looked at outgassing, and assumed that its not relevant due to slow temp rise not producing rising force. But that does not cover possibility that the electromagnetic resonances are somehow vaporising and ejecting structure at much higher speeds. At .0012N thrust with 1kW input (and 100% efficiency) a rocket would need exhaust velocity of 1.6e6 m/s and consume around 0.8ng per second - damned difficult to weight with required sensitivity and hard to spot except by looking for evidence in the gases within the chamber as metals will condense out quickly.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      But that does not cover possibility that the electromagnetic resonances are somehow vaporising and ejecting structure at much higher speeds.

      Ah yes, the "I'm sure I thought of something the experts didn't" response.
      Metal doesn't just vaporise. It takes a lot of energy to free atoms from a metal lattice, which would require the metal to be visibly glowing hot, which is not what happens in the drive.

  • Do we have any idea how this works? And do we know if we will be able to optimize this at all to get better performance?

    • One proposed theory is that it works by exploiting unruh radiation. That explanation relies on the premise that inertia is quantum in nature, and so there can be anomalies between discrete quantum levels of inertial interactions.

      https://arxiv.org/abs/1604.034... [arxiv.org]

      The author has proposed that this mechanism may also be responsible for some other observational anomalies.

      http://phys.org/news/2011-07-g... [phys.org]

    • Do we have any idea how this works?

      It doesn't. It's a horribly difficult experiment to measure and IF EM drives worked then they are effectivly perpetual motion machines, in that you could build a free energy device out of one.

      • How would one build a free energy device out of a working EM drive?
        • The glib answer is "go fast".

          power = force * velocity

          So if v is high enough anf f is fixed (as claimed with the EM drive) then eventually the kinetic energy power will go over the power in, unless it's the much lower thrust of a photon drive.

          It's not practical at 1.2mN/kW, but that's irrlevant to the physics.

    • by poodlediagram ( 1944244 ) on Saturday November 19, 2016 @04:43AM (#53320847)
      IAATP working on quantum electrodynamics (QED) and other theories.

      The fundamental problem with this experiment is that it appears to violate conservation of momentum. This violation is not something that can be discarded easily: it has been confirmed directly and indirectly in millions of experiments over decades.

      Momentum conservation is also a cornerstone of quantum field theory (QFT) and it is a symmetry which survives quantization. The entire Standard Model (SM) is a momentum-conserving QFT. The SM has been confirmed to a high accuracy in particle accelerators for many years. Any violation of momentum conservation would have been quickly noticed. You cannot simply invoke 'quantum mechanics', 'zero point', 'vacuum fluctuations', etc. to explain excess thrust. Momentum conservation is fundamental, both classically and quantum mechanically.

      So what about the EM drive results? There is a possibility that some new physics is at play, however it is vastly more likely that there is a systematic error which has not been eliminated. (If I had to guess I would imagine that because a large amount of RF energy is being pumped into large metal cavities, the apparatus is resting at the bottom of a standing wave potential.)

      The way to finally confirm or refute this is to take the drive into space. In this case, it is almost certain that the net thrust would be equal to the momentum of the photon flux leaving the drive.
      • The fundamental problem with this experiment is that it appears to violate conservation of momentum.

        And conservation of energy---once it's going fast enough. It violates ALL the things.

        IAATP working on quantum electrodynamics (QED) and other theories.

        Out of interest, do the succession of reasons why it "works", you know: it's relativity! er no it's virtual particles! er no it's the Unruh effect! actually cause you physical pain?

        • Out of interest, do the succession of reasons why it "works", you know: it's relativity! er no it's virtual particles! er no it's the Unruh effect! actually cause you physical pain?

          No. Those are what are called "speculation". As in "we see it working, but we have no idea why or how. But it could be..."

          As to conservation of momentum/energy. They're not necessarily laws of nature, you know. As soon as something comes along that "violates conservation of...", those two rules become "special cases", just

          • by poodlediagram ( 1944244 ) on Saturday November 19, 2016 @07:28AM (#53321145)
            <quote>Now, does it work? No idea, frankly. I'm more inclined to believe the results of, you know, an actual test than someone who didn't do the test but insists it can't work in spite of the test....</quote>

            It's difficult to convey to a non-physicist just how accurately and consistently quantum field theory describes nature. Physicists routinely make calculations which have lower uncertainly than the best experiments. For example the anomalous magnetic moment (https://en.wikipedia.org/wiki/Anomalous_magnetic_dipole_moment) is in agreement with theory to ten significant figures.

            Physicists tend to be fairly cautious describing results, but when it comes to basic theory at energies up to a few hundred GeV we are confident that we have *all* physical effects well and truly nailed. This doesn't mean that we can always solve the equations perfectly: quantum mechanics is hard, but the equations themselves are almost beyond reproach.

            It's not undeserved hubris: it's trillions of independent experiments, billions of dollars and hundreds of thousands of man-years working on the theory by lots of very smart people. The theory, quantum field theory (QFT), is simple, consistent and universal. It describes everything we can see around us, with the exception of gravity.

            If you ask an actual physicist what he or she thinks of the EM drive, they will overwhelmingly say that is is highly likely there is an unresolved source of error because violation of moment conservation has never been observed and is inconsistent with QFT.
  • by Alain Williams ( 2972 ) <addw@phcomp.co.uk> on Saturday November 19, 2016 @04:08AM (#53320771) Homepage

    put this on top of a rocket and have the thing move around upstairs: from low earth orbit round the moon and back should convince most people. It might take a few months to make the trip, that does not matter.

  • by ihaveamo ( 989662 ) on Saturday November 19, 2016 @04:13AM (#53320791)
    I've been following this for a year or so - very interesting. Over at Nasa Space Flight board [nasaspaceflight.com] there are a lot of people making these EM drives in their back yard, with varying results. A lot of this comes from the original work by Roger Shawyer. He has stated that he will show a drone running EM drive in 2017. If that works ...that would change everything. Cheap access to space would mean space-based solar arrays for terrestrial use. Here's [ibtimes.co.uk] an article about his patent. There's also some very strange results with laser timing through an EM drive cavity. Almost like spacetime is being warped.
  • by CustomSolvers2 ( 4118921 ) on Saturday November 19, 2016 @04:41AM (#53320839) Homepage
    ... are more or less the same ones than before (= very unclear setup, situation very unlikely to represent the claimed break of the conservation laws, highly restricted conditions not telling much, etc.).

    Summary of my impressions after quickly reading this paper:

    - The actual methodology generating the thrust isn't clearly explained, 95% of this paper is about the testing conditions (measurements, sources of error, assumptions, etc.). Although I assume that detailed explanations on this front might drive to a level of clarity similar to the one of the tests, as explained in the next point.

    - Complex testing setup which is very difficult to be adequately understood from outside. It seems that only people with actual experience under these specific conditions (and, ideally, with physical access to an equivalent setup) are in a position to critically analyse these tests and be specific about the (very likely IMO) source(s) of error.

    - Even by ignoring the two aforementioned points, plainly believing that everything is fine and just analysing the results, there are various issues which are somehow against the reliability of this experiment and related out-of-proportion assumptions. Examples in fig. 9: a maximum displacement below 0.005 micrometres (extrapolating such a top performance to interstellar travels is sensible?!); assuming that the error in the measurements remain constant under different conditions (?!); testing just 3 different scenarios (40, 60, 80 W) and getting counter-intuitive results (30/40 = 0.75; 106/60 = 1.76; 76/80 = 0.95; 60 W delivering the best performance?!).
    Fig. 19 is even more descriptive by showing a tremendous variability of the measurements; in the best-performing 60 W scenario, they vary from 130 to 45 micronewtons!! With only a few cases being similar enough (85 and 92); out of all the about 20 cases, there are only a few which are identical under the given conditions.
    • Re: (Score:3, Insightful)

      by Anonymous Coward

      > The actual methodology generating the thrust isn't clearly explained, 95% of this paper is about the testing conditions

      Well duh, this paper is about proving existence. It's a physical test, it doesn't have to explain why it works. If the models don't fit reality then it is the models that are wrong, not reality. Hence the details about the test infrastructure. That results don't have to make sense, they just need to show that existing models are invalid.

      • this paper is about proving existence. It's a physical test, it doesn't have to explain why it works.

        Sorry, perhaps I wasn't too clear. I meant that the EM-drive setup (what generates the claimed thrust) wasn't properly explained and that it is probably like the testing setup anyway (i.e., too complex and intrincate to be reproduced/properly understood by anyone other than those with actual access to these installations).

        That results don't have to make sense

        In fact, they do have to make sense. Making sense is what differentiates science (common sense, logic, properly-understood phenomena, etc.) and other "fields" like magic, blind-trust-based

  • Imagine (Score:5, Funny)

    by jsim ( 1341765 ) on Saturday November 19, 2016 @06:28AM (#53321013)

    Just imagine this gizmo powered with cold fusion!

  • The explanations are plausible (exploitation of more of those weird quantum mechanical effects). If it works out, we get to cheat Newton, basically stealing momentum from the universe's underlying framework. Or the simulation engine, if that's what it is.

    After that, it's an engineering problem to make it efficient. You'll still have to get out of the gravity well some other way, but after than, you can flit about anywhere nearly for free.

    I'm trying to remain skeptical, but this really is what every sci-fi n

    • by PPH ( 736903 )

      You'll still have to get out of the gravity well some other way

      Unless there is something about the gravity well that makes this thing work. Until we understand its principle of operation, its just a curiosity. Launch one out of the solar system and compare delta V with a continuous thrust model and see if it works. I doubt we are far enough along understanding it to make that kind of investment.

  • by pere ( 23710 ) on Saturday November 19, 2016 @07:00AM (#53321081)

    Just to put the numbers in perspective. A force of 1.2mN/kW is equivalent of a force of 0.12 gram.

    A Tesla SP85 has a maximum effect of 350KW. This would (in theory) produce a force of roughly 40 grams, the weight of 10 sugar cubes.
    A Nuclear submarine is able to produce an effect of 100MW, giving a theoretical force of 10kg.
    A medium nuclear power plant is producing roughly 1000MW, and a force of 100kg.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      Well, that's total gibberish. Who the hell modded it up? Slashdot really is on its last legs.

  • Bearing in mind that all this is just a fun exercise, and there's no reason to believe that the 1.2 mN/kW thrust will scale to megawatts of power, here's how long it would take to get to Mars if this finding scales to a practical spaceship drive:

    • Assume solar panels in space [quora.com] can give you 2.5kW per square meter, and a hypothetical spacecraft has a 20 x 40 meter solar array giving 2 MW
    • 1.2 mN/kW == 1.2 N/MW, so at 2MW you're getting 2.4 Newtons of thrust.
    • Let's say that the craft weighs 100 tonnes, that gives
    • by lgw ( 121541 )

      If it works at all, then presumably the prototype didn't stumble on the most efficient possible design.

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