Now it looks like, yes, it
used to be Too good to be true. Scientists from the Technical University of Dresden (TU Dresden) seem to have conclusively proven that the EmDrive does not actually produce thrust. They provide compelling evidence that small indications of thrust in previous research were simply false positives produced by outside forces.
How the EmDrive should work
Credit: AndSus / Adobe Stock
In the EmDrive, the company owning the rights to the invention says, “thrust is produced by amplifying the radiation pressure of an electromagnetic wave propagating through a resonant waveguide assembly.” In simpler words, trapped microwaves bounce around a specially shaped, closed container, producing a thrust that pushes the whole thing forward.
They also claim that while the EmDrive isn’t exactly up to speed with Newton’s third law, the company says it’s perfectly consistent with the second:
“This is based on Newton’s second law, which defines force as the speed at which momentum changes. So an electromagnetic (EM) wave that travels at the speed of light has a certain momentum that it will transfer to a reflector. , resulting in a small forcing. ”
Interest in the EmDrive was understandable given what it was supposed to do. Speak against
Popular mechanics Last year, Mike McCulloch, the leader of DARPA’s EmDrive study, described how the engine “could transform space travel and watch craft quietly lift off launch pads and reach beyond the solar system.” He cited his excitement at being able to get to Proxima Centauri from here in just 90 human years – 4.2465 light years away.
It does not work. Yes it does. No that is not necessary.
EmDrive from NASA EagleworksCredit: NASA / Wikimedia Commons
DARPA, part of the United States Department of Defense, is just one of the organizations investigating the claims for the EmDrive. In 2018, the agency invested $ 1.3 million to study the device in research to be completed in May, barring major last-minute breakthroughs.
Teams from around the world have been testing Shawyer’s idea since it was introduced and often released conflicting test results. This may have to do with the fact that teams that detected an EmDrive thrust at all reported disappearingly small amounts of it, measured in milliNewtons (mN). One mN equals approximately 0.00022 pounds of force.
As Paul Sutter wrote in an opinion piece for Space.com:
“Since the introduction of the EmDrive concept in 2001, a group claims to have measured a net force coming out of its device every few years. But these researchers are measuring an incredibly small effect: a force so small that it doesn’t even a piece of paper. This leads to significant statistical uncertainty and measurement errors. ”
To get an idea of how miniscule these results are, consider that the possible thrust reported by NASA in 2014 of 30-50 micro-Newtons is roughly equal to the weight of a large ant. Chinese researchers claimed a detection of 720 mN in their tests. That would be 72 grams of thrust. An iPhone 11 with cover weighs 219 grams.
Too small to stand out against background noise
These small amounts of EmDrive thrust are at the heart of what the researchers at TU Dresden say: the effects are just too small to rule out effects that don’t come from the EmDrives at all. The researchers have just published three articles. The title of a “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 powered up their EmDrive based on NASA’s EmDrive, they too witnessed small amounts of apparent thrust.
But, says Martin Tajmar of UT Dresden to the German media channel GreWi, they quickly realized what was going on: “When current flows into the EmDrive, the motor heats up. This also causes the mounting elements on the scale to warp. which creates the scale to go to a new zero point. We have been able to prevent that in an improved structure. ”
Putting the kibosh on the results of other researchers, the authors of the studies write:
“Using a geometry and operating conditions close to the White et al. Layers model and reporting positive results published in the peer-reviewed literature, we did not find thrust values within a wide frequency band including different resonant frequencies. data limits any abnormal thrust below the force equivalent of classical radiation for a given amount of power. This puts strong limits on all proposed theories and precludes previous test results by more than three orders of magnitude. ”
This seems to be the definitive ending of the EmDrive story.
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