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

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  • The proposed EmDrive captured the public’s imagination with the promise of a super-fast space trip that broke the laws of physics.
  • Some researchers have detected actions from EmDrive that seemed to prove their validity as a technology.
  • A new authoritarian study says no, those results were just “positive fakes.”
    • When Roger Shawyer’s EmDrive was first proposed in 2001, it seemed too good to be true. The proposed electromagnetic unit (“Em” for short) needed no fuel and was therefore so light that it promised to allow travelers to traverse the cosmos at unprecedented speeds. It doesn’t matter that EmDrive’s operation seemed to violate Newton’s third law of motion, that of every action producing an equal and opposite reaction.

    Now it seems so
    was too beautiful to be true. Scientists at the Dresden University of Technology (TU Dresden) seem to have conclusively proven that EmDrive does not actually produce any traction. They provide some convincing evidence that small thrust indices in previous research were simply false positives produced by external forces.

    How EmDrive should work


    Credit: AndSus / Adobe Stock

    In EmDrive, says the company that owns the rights to the invention, “Propulsion is produced by amplifying the radiation pressure of an electromagnetic wave propagated by a resonant waveguide assembly.” Simply put, the trapped microwaves jump around a specially closed container, producing a push that pushes everything forward.

    They also state that while EmDrive isn’t exactly in terms of talking to Newton’s third law, the company says it’s perfectly in line with the second:

    “This is based on Newton’s second law, where force is defined as the rate of change of momentum. Thus, an electromagnetic wave (EM), which travels at the speed of light, has a certain impulse that it will transfer to a reflector, resulting in a small force. ”

    The interest in EmDrive was understandable given what it had to do. Talking to
    Popular mechanics last year, Mike McCulloch, leader of DARPA’s EmDrive investigation, described how the engine could “transform space travel and see boats silently rise from launch pads and reach beyond the solar system.” He mentioned his enthusiasm to be able to reach the Proxima Centauri from here – 4,2465 light-years away – in just 90 human years.

    Not working. Yes Yes. No no.

    EmDrive at NASA EagleworksCredit: NASA / Wikimedia Commons

    DARPA, which is part of the US Department of Defense, is just one of the organizations investigating claims made for EmDrive. In 2018, the agency invested $ 1.3 million to study the device in research that will end in May, with the exception of any significant last-minute discoveries.

    Teams around the world have been testing Shawyer’s idea since it was introduced and have released often conflicting test results. This may be related to the fact that teams that detect any EmDrive pulse reported very small amounts, measured in milliNewtons (mN). One mN is equal to about 0.00022 kilograms of force.

    As Paul Sutter wrote in an article published for Space.com:

    “Since the introduction of the EmDrive concept in 2001, every few years, a group claims to have measured a net force from its device. But these researchers measure an incredibly small effect: a force so small that it could not even cut a piece of paper. This leads to statistically significant uncertainty and measurement error. ”

    To understand how tiny these results are, consider that the possible pushing force reported by NASA in 2014 of 30-50 micro-Newtons is roughly equivalent to the weight of a large ant. Chinese researchers claimed to detect 720 mN in their tests. That would be 72 grams of force. An iPhone 11 with a case weighs 219 grams.

    Too small to stand out against background noise

    These small amounts of EmDrive force underlie what TU Dresden researchers say: The effects are simply too small to exclude effects that do not come from EmDrives at all. Researchers have just published three papers. The title of a “High-precision pressure measurement of EmDrive and elimination of false-positive effects” tells the story. The other two studies are here and here.

    When the UT Dresden team started their EmDrive based on NASA’s EmDrive, they also witnessed small amounts of apparent force.

    However, says Martin Tajmar of UT Dresden to the German press GreWi, they soon realized what was happening: “When current flows in EmDrive, the engine heats up. This causes the fasteners on the scale to deform, causing let’s move to a new zero point. We were able to prevent this in an improved structure. ”

    Putting kibosh on the results of other researchers, the study authors write:

    “Using a geometry and operating conditions close to the model of White et al., Which reported positive results published in the literature, we did not find pulse values ​​in a wide frequency band, including several resonant frequencies. Our data limits anything below the force equivalent to classical radiation to a certain amount of power. This offers strong limits to all proposed theories and excludes the results of previous tests by more than three orders of magnitude. ”

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

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