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China NASA Space Earth Transportation Technology

China Claims Tests of 'Reactionless' EM Drive Were Successful (popsci.com) 470

An anonymous reader quotes a report from Popular Science: The "reactionless" Electromagnetic Drive, or EmDrive for short, is an engine propelled solely by electromagnetic radiation confined in a microwave cavity. Such an engine would violate the law of conservation of momentum by generating mechanical action without exchanging matter. But since 2010, both the United States and China have been pouring serious resources into these seemingly impossible engines. And now China claims its made a key breakthrough. Dr. Chen Yue, Director of Commercial Satellite Technology for the China Academy of Space Technology (CAST) announced on December 10, 2016 that not only has China successfully tested EmDrives technology in its laboratories, but that a proof-of-concept is currently undergoing zero-g testing in orbit (according to the International Business Times, this test is taking place on the Tiangong 2 space station). If China is able to install EmDrives on its satellites for orbital maneuvering and altitude control, they would become cheaper and longer lasting. Li Feng, lead CAST designer for commercial satellites, states that the current EmDrive has only a thrust of single digit millinewtons, for orbital adjustment; a medium sized satellite needs 0.1-1 Newtons. A functional EmDrive would also open up new possibilities for long range Chinese interplanetary probes beyond the Asteroid belt, as well freeing up the mass taken up by fuel in manned spacecraft for other supplies and equipment to build lunar and Martian bases. On the military side of things, EmDrives could also be used to create stealthier, longer lasting Chinese surveillance satellites.
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China Claims Tests of 'Reactionless' EM Drive Were Successful

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  • by slashmydots ( 2189826 ) on Thursday December 22, 2016 @02:27AM (#53535691)
    So you flip the switch and it goes that way but we have no idea why. I say strap it to a spaceship. That's good enough for me.
    • by arth1 ( 260657 )

      So you flip the switch and it goes that way but we have no idea why. I say strap it to a spaceship. That's good enough for me.

      Not good enough for the spaceship, though. Adding a substantial amount of mass to gain a couple of millinewtons of trust isn't too helpful.

      • Re: (Score:3, Funny)

        by Anonymous Coward
        But once you have enough trust you can just tell people it's moving faster, and they will believe you.
      • Re:I have an idea (Score:5, Insightful)

        by johannesg ( 664142 ) on Thursday December 22, 2016 @05:02AM (#53536005)

        Not good enough for the spaceship, though. Adding a substantial amount of mass to gain a couple of millinewtons of trust isn't too helpful.

        Those millinewtons can be applied over a very long time though, allowing significant speeds to be achieved. Moreover, missions to far-away objects would no longer have their lifetimes limited by running out of fuel.

        • 'missions to far-away objects would no longer have their lifetimes limited by running out of fuel.' - well - ...
          At the NASA EMdrive recent published thrust, there are no plausible long-distance missions it could be better at than a conventional ion engine.
          This is simply because the power generated per kilo of solar panels is small.
          This sets an acceleration limit, because you need power to accelerate, which means you're swapping several years of fuel for a ion engine for heavier solar panels, and it's not a

        • The main issue, and the one this solves, isn't running out of fuel, it's running out of reaction mass.

    • Re:I have an idea (Score:4, Interesting)

      by serviscope_minor ( 664417 ) on Thursday December 22, 2016 @04:40AM (#53535969) Journal

      Trouble is that's super expensive. There are two choices here:

      1. The EM drive works, which means there is a substantial gap in the laws of physics which have already passed very many far, far more stringent tests than the one in this article, implying thousands of other unrelated experiments were flawed in a consistent way.
      2. The EM drive doesn't work and there was a flaw in this and a rather tricky experiment.

      If you're about to blow a spaceship's worth of cash on something, you might first want to consider how tricky the experiment is. Putting in a kilowatt (think domestic microwave) and measuring a milinewton (a grain of rice?) is hard. Think of all the confounding factors. Now consider none of the other tests have stood up to peer review yet.

      Which do you think is more likely now, 1 or 2?

      And would that influence your decision to blow a few tens of millions on it?

      • What, no third option between the other two of 'oh yes there is an effect but we overlooked something so that it does conserve momentum'?
        It's hard to know whether your math model with all of its simplifications really fits the reality.

        • like what? I could hypothesize that it's actually a unicorn attractor and when it's switched on, any nearby invisible unicorns will come and give it a judge in the right direction.

          Thing is, for it to conserve momentum, there's needs to be reaction mass of some sort.

          • So you'll sooner consider the hypothesis that conservation of momentum is broken than consider the hypothesis that there's radiation leaking in a place they haven't looked yet. No wonder you believe in unicorns.

            • So you'll sooner consider the hypothesis that conservation of momentum is broken than consider the hypothesis that there's radiation leaking in a place they haven't looked yet.

              Physics, it works, bitches.

              https://xkcd.com/54/ [xkcd.com]

              You know we can calculate the maximum possible thrust from leaked radiation and it's 3uN/kW, vastly smaller than the amount reported. Therefore it isn't that.

              No wonder you believe in unicorns. :blink:

              Ya know, sure why not. If you can believe we'll fly around the solar system on a perprt

          • by jeremyp ( 130771 )

            Photons have momentum but no mass.

      • If you're about to blow a spaceship's worth of cash on something, you might first want to consider how tricky the experiment is.

        Let's launch it on one of Japan's new "scientific" solid rocket boosters, that should help keep costs down :)

  • by Anonymous Coward

    I followed one of the links, and got a picture claiming to be a 'test' at Eagleworks, and the words 'in air' (without saying exactly what is in air).

    Look, the heat sink for the power amp is mechanically linked to the large end of the cavity... Doesn't it seem to anyone with even a tiny bit of experience with simple air convection from a bigass heat sink that this is the exact configuration you'd most expect to exhibit such effects, and of the reported size too?

    Eagleworks are apparently smart people... what

  • BULLSHIT (Score:3, Informative)

    by 110010001000 ( 697113 ) on Thursday December 22, 2016 @08:20AM (#53536547) Homepage Journal
    More fake news. Go to CAST website. THERE IS NOTHING THERE ABOUT IT. And the website is in English too. Stop posting this bullshit about the EmDrive. It is this decades eCat.
    • Re:BULLSHIT (Score:5, Informative)

      by l0n3s0m3phr34k ( 2613107 ) on Thursday December 22, 2016 @01:10PM (#53538529)
      I'm pretty sure I remember you have previous posts calling people "space nutters", and are pretty rabid in attacking anything outside mainstream NASA. The claim that CAST has nothing just because the English version has nothing means nothing...unless you've gone through the Chinese language version and can prove the two sites contain the same information.

      I found another reference in English at http://spaceflight101.com/shijian-17-rendezvous-with-chinasat-5a/ [spaceflight101.com]: "and debuting a Hall-Effect Thruster system for use on future Chinese GEO satellites"

      Digging into this via Google Translate does provide far more information. The information your claiming doesn't exist actually DOES exist, on the stdaily.com article. It's just all in Chinese, so you have to put some effort in to translate it. My link is at translate.google.com [google.com] and https://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=auto&tl=en&u=http://digitalpaper.stdaily.com/http_www.kjrb.com/kjrb/html/2016-12/11/content_357005.htm%3Fdiv%3D-1&usg=ALkJrhhkYPDNKL_9BxSu6OAkt5KIHsse9Q [googleusercontent.com] but I don't know if this link will work for anyone else.

      Using Google page translation:

      Chen Yue said: "We use the classic electromagnetics and electrodynamics to design several different shapes of thrusters, theoretical analysis can generate thrust thrust, and through the test of the thrust, the results in line with theoretical analysis. Science and Technology Daily Beijing December 10 " Roger Xiaoe in an interview was also asked this "eternal" problem, he made it clear that the EM engine does not violate Newton's law of mechanics: "EM engine in a direction to generate propulsion, if circumstances permit, will In another direction, the momentum of the whole process is conserved. "This explanation is considered ambiguous.

      "We have successfully developed several specifications of several prototype principle, the establishment of experimental verification platform to complete the milli-level micro thrust measurement test, through several years of repeated tests and the corresponding interference factor investigation test, confirm that the type of thruster Thrust exists. "Chen Yue introduced that they have completed the test device can be used for flight test development, is in orbit verification.

      "This technology is currently in the latter stages of the proof-of-principle phase, with the goal of making the technology available in satellite engineering as quickly as possible," said Li Feng, chief architect of the China National Space Technology Institute's communications satellite division. , The principle prototype volume, thrust is small, require special engineering methods, optimize the cavity design, improve the cavity quality factor, reduce the loss, the microwave energy is more effective for generating thrust. At present, the thrust is measured to micro-cow level to millennial level, at least to improve the level of 100 cents or even cattle-level satellite can be used for attitude control, orbit and so on.

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