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The “future” of space travel has just slipped into the past



  • The proposed EmDrive breaks the laws of physics with the promise of ultrafast space travel, attracting the imagination of the public.
  • Some researchers have found that the thrust of EmDrive seems to prove its effectiveness as a technology.
  • A new authoritative study shows that no, these results are just “false positives.”

  • When Roger Shawyer’s EmDrive was first proposed in 2001, it seemed too good to be true. The proposed electromagnetic drive (“Em” for short) requires no fuel and is therefore so lightweight that it enables travelers to slide through the universe at unprecedented speeds. It doesn̵
    7;t matter, the working principle of EmDrive seems to violate Newton’s “Third Law of Motion”, which has an equal and opposite reaction to every action.

    Now it seems that yes,
    used to be incredible. Scientists at the Dresden University of Technology (TU Dresden) seem to have concluded that EmDrive does not actually produce any thrust. They provided some convincing evidence that the small signs of thrust in previous studies were only false positives produced by external forces.

    How should EmDrive work


    Image source: AndSus / Adob​​e Stock

    The company that owns the rights to the invention said that in EmDrive, “thrust is generated by amplifying the radiation pressure of electromagnetic waves propagating through the resonant waveguide assembly.” In simple terms, trapped microwaves bounce around a specially shaped closed container , Generating thrust, pushing the entire object forward.

    They also asserted that although EmDrive does not fully comply with Newton’s third law, the company stated that it is fully consistent with the second law:

    “This relies on Newton’s second law, where force is defined as the rate of change of momentum. Therefore, an electromagnetic wave traveling at the speed of light has a certain momentum, and it will be transferred to the reflector to produce a small change. Force.”

    Considering what it should do, the interest in EmDrive is understandable.speak
    Popular Mechanics Last year, Mike McCulloch, the head of the DARPA EmDrive survey, described how the engine “changes space travel and sees the spacecraft quietly lift off from the launch pad and reach beyond the solar system.” He mentioned his excitement that he could reach Proxima Centauri 4.2465 light-years away from here in just 90 years.

    It does not work. Yes, it does. No, it’s not.

    EmDrive by NASA EagleworksImage credit: NASA / Wikimedia Commons

    DARPA is part of the US Department of Defense and is just one of the organizations investigating EmDrive’s claims. In 2018, the agency invested 1.3 million U.S. dollars in research on the device, and unless there are any major latest breakthroughs, the research will end in May this year.

    Since Shawyer’s idea was introduced, teams around the world have been testing it and often publishing conflicting test results. This may be related to the fact that the thrust reported by the team that detected all EmDrive thrust has almost disappeared, measured in millinewtons (mN). mN is equal to approximately 0.00022 pounds of force.

    As Paul Sutter wrote in a column on Space.com:

    “Since the introduction of the EmDrive concept in 2001, a team has claimed to measure the net force from its equipment every few years. But these researchers are measuring incredibly small effects: forces that are so small that they cannot be yielded. . A piece of paper. This will lead to significant statistical uncertainty and measurement errors.”

    For the trivial significance of these results, consider the 30-50 micronewton thrust reported by NASA in 2014 that is approximately equal to the weight of a large ant. Chinese researchers claim to have detected 720 mN in their tests. That will be 72 grams of thrust. IPhone 11 with a case weight of 219 grams.

    Too small to distinguish from background noise

    These tiny thrusts of EmDrive are the core of what the researchers of Dresden University said: the impact is too small to rule out the impact that is not from EmDrive at all. Researchers have just published three papers. A title titled “EmDrive’s high-precision thrust measurement and elimination of false positive effects” tells the story. Two other studies are here and here.

    When the UT Dresden team turned on EmDrive based on NASA’s EmDrive, they also witnessed a slight apparent thrust.

    However, Martin Tajmar of UT of the University of Dresden told German media GreWi that they quickly realized what was happening: “When power flows into EmDrive, the engine becomes hot. This also causes the scale. The fixing elements on the upper part warped, causing the scale to move to a new zero point. We can avoid this by improving the structure.”

    The authors of these studies put Kibosh on the results of other researchers and wrote:

    “Using the geometry and operating conditions close to White et al.’s model, which reports positive results published in peer-reviewed literature, we found that there is no thrust value in a wide frequency band including several resonance frequencies. Our data Limiting any abnormal thrust below the equivalent effectiveness of classical radiation at a given power. This provides a strong limit to all the proposed theories and excludes the previous test results by more than three orders of magnitude.

    This seems to be the final end of the EmDrive story.

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