Now it seems so
era too good to be true. Scientists at Dresden University of Technology (TU Dresden) seem to have conclusively shown that EmDrive does not produce any thrust. They provide some compelling evidence that the small indications of thrust in previous research were simply false positives produced by external forces.
How EmDrive is supposed to work
Credit: AndSus / Adobe Stock
At EmDrive, says the company that owns the rights to the invention, “the thrust is produced by amplifying the radiation pressure of an electromagnetic wave propagated through a set of resonant waveguides.” . Simply put, trapped microwaves bounce around a specially closed container, producing thrust that pushes everything forward.
They also claim that while the EmDrive does not exactly meet the terms of Newton’s third law, the company says it is 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. Therefore, an electromagnetic wave (MS) that travels at the speed of light has a certain momentum that it will transfer to a reflector, giving rise to a small force “.
The interest in the EmDrive has been understandable given what it was supposed to do. Talking to
Popular mechanics last year, Mike McCulloch, leader of DARPA’s EmDrive research, described how the engine could “transform space travel and see spacecraft silently rise from launchers and reach beyond the solar system.” He mentioned his excitement to be able to get from here to Proxima Centauri – 4,2465 light-years away – in just 90 human years.
Out of order. Yes, it is. No, no.
EmDrive from NASA EagleworksCredit: NASA / Wikimedia Commons
DARPA, which is part of the U.S. Department of Defense, is just one of the organizations investigating claims for EmDrive. In 2018, the agency invested $ 1.3 million to study the device in research that will end this May, unless significant last-minute advances are made.
Teams around the world have been testing Shawyer’s idea since it was introduced and published often conflicting test results. This may have to do with the fact that computers detecting any EmDrive thrust have reported very small amounts, measured in milliNewtons (mN). One mN equals about 0.00022 pounds of force.
As Paul Sutter wrote in a post for Space.com:
“Since the introduction of the EmDrive concept in 2001, every few years a group claims to have measured a net force coming from their device. But these researchers measure an incredibly small effect: a force so small it couldn’t even piece a piece of paper. This leads to significant statistical uncertainty and measurement error. ”
To get an idea of the minusculeness of these results, consider that the possible thrust force reported by NASA in 2014 of 30-50 micro-newtons is approximately the weight of a large ant. Chinese investigators have claimed 720 mN detection in their tests. It would be 72 grams of thrust. An iPhone 11 with a case weighs 219 grams.
Too small to stand out against background noise
These small amounts of EmDrive drive are at the heart of what TU Dresden researchers say: the effects are too small to rule out effects that don’t really come from EmDrives. Researchers have just published three articles. The title of a “High-Precision Emergency Thrust Measures and Elimination of Positive False Effects” tells the story. The other two studios are here and here.
When the UT Dresden team activated their EmDrive based on NASA’s EmDrive, they also witnessed small amounts of apparent thrust.
However, says Martin Tajmar of UT Dresden to the German media GreWi, they soon realized what was happening: “When energy flows in the EmDrive, the engine heats up. This also causes the elements of fixing the scale deforms, causing the ladder to move to a new zero point. We were able to avoid it in an improved structure. ”
Putting the kibosh in the results of other researchers, the authors of the studies write:
“Using geometry and operating conditions close to the model of White et al. They reported positive results published in the peer-reviewed literature, we did not find thrust values within a wide frequency band that include multiple frequencies. Our data limit any abnormal thrust to less than the equivalent force of classical radiation for a given amount of power.This provides strong limits to all proposed theories and excludes previous test results in more than three orders of magnitude. magnitude. ”
This would seem to be the definitive end of EmDrive’s story.
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