The ‘future’ of space travel has just slipped into the past

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 super – fast space travel that violated the laws of physics.
  • Some researchers have detected thrusts from the EmDrive that appear to be valid as a technology.
  • A new, authoritative study says, no, the results were merely ‘false positives’.
    • When Roger Shawyer’s EmDrive was first introduced in 2001, it seemed too good to be true. The proposed electromagnetic propulsion (“Em” for short) required no fuel and was therefore so lightweight that it promised to propel travelers across the cosmos at unprecedented speeds. No matter that the work of the EmDrive was apparently contrary to Newton’s Third Law of Motion, the fact that every action produces an equal and opposite reaction.

    Now it looks like it
    wash too good to be true. Scientists from the Dresden University of Technology (TU Dresden) seem to prove unequivocally that the EmDrive does not really work. They provide compelling evidence that small indications of thrust in previous research were merely false positive results produced by outside forces.

    How the EmDrive is supposed to work


    Credit: AndSus / Adobe Stock

    In the EmDrive, the company that owns the rights to the invention says, “thrust is produced by amplifying the radiative pressure of an electromagnetic wave propagated by a resonant waveguide assembly.” In simpler words, trapped microwaves bounce around a specially shaped closed container, giving a push that pushes the whole thing forward.

    They also claim that while the EmDrive does not speak exactly to Newton’s third law, the company says it is completely consistent with the second:

    “It is based on Newton’s second law, where force is defined as the rate of change of momentum. Thus, an electromagnetic (EM) wave moving at the speed of light has a certain momentum that it moves to a reflector will transmit, leading to a small force. ‘

    Interest in the EmDrive was understandable if we wanted to do it. Talk to
    Popular mechanics last year, Mike McCulloch, the leader of DARPA’s EmDrive survey, described how the engine could ‘transform space travel and see vessels quietly pull up from push-ups and extend beyond the solar system.’ He said he was excited to be able to get to Proxima Centauri – just 4.2465 light-years away – in just 90 man-years.

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

    NASA Eagleworks’ EmDriveCredit: NASA / Wikimedia Commons

    DARPA, part of the U.S. Department of Defense, is only one of the organizations investigating the claims for the EmDrive. In 2018, the agency invested $ 1.3 million to study the device in research that will conclude in May, with the exception of last-minute breakthroughs.

    Teams from around the world have been testing Shawyer’s idea since its launch and have often released conflicting test results. This may have to do with the fact that teams that detect an EmDrive stretch at all have reported disappearing small amounts of it, measured in milliNewtons (mN). An MN equals about 0.00022 pounds of power.

    As Paul Sutter wrote in a headline for Space.com:

    ‘Since the launch of the EmDrive concept in 2001, a group has been claiming a net power from its device every few years. But these researchers measure an incredibly small effect: a force so small that it is a piece of paper. This leads to significant statistical uncertainty and measurement errors. ”

    Consider that the potential thrust that NASA reported in 2014 of 30-50 micro-Newtons is roughly equal to the weight of a large ant. Chinese researchers claimed that 720 mN was detected in their tests. That would be 72 grams of push. An iPhone 11 with a case weighs 219 grams.

    Too small to stand up against background noise

    These small amounts of EmDrive congestion are at the heart of what the TU Dresden researchers say: The effects are simply too small to eliminate effects that do not come from the EmDrives at all. The researchers have just published three articles. The title of one “High-Accuracy Thrust Measurements of the EmDrive and Elimination of False-Positive Effects” tells the story. The other two studies are here and here.

    When the UT Dresden team turned on their EmDrive based on NASD’s EmDrive, they also saw small amounts of apparent stretch.

    Martin Tajmar from UT Dresden, to the German media GreWi, says they soon realized what was going on: “When the power flows in the EmDrive, the engine warms up. It also causes the fasteners on the scale to warp, causing the scale to move to a new zero point. We were able to prevent it in an improved structure. ”

    The authors of the studies write the kibosh on the results of other researchers:

    Using a geometry and operating conditions close to the model by White et al., Who published positive results in the peer-reviewed literature, we found no pressure values ​​within a wide frequency band, including multiple resonant frequencies. Our data limit any below the power equivalent of classical radiation for a given amount of power. It offers strong limits to all proposed theories and excludes previous test results by more than three orders of magnitude. ”

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

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