NASA Eagleworks Has Tested an Upgraded EM Drive

An anonymous reader writes: A team of researchers at NASA's Eagleworks Laboratories recently completed yet another round of testing on Engineer Roger Shawyer's controversial EM Drive. While no peer reviewed paper has been published yet, engineer Paul March posted to the NASA Spaceflight forum to explain the group's findings. From the article: "In essence, by utilizing an improved experimental procedure, the team managed to mitigate some of the errors from prior tests — yet still found signals of unexplained thrust."

Comments

Re:Scientists

[DrJimbo]

The problem is not the absolute smallness of 100 micro-Newtons. The problem is the relative size of 100-micro-Newtons compared to the forces that exist in the experimental apparatus. It is like confusing absolute signal level with the signal to noise ratio. Yes, we can easily measure the weight of a snowflake. But if the total thrust from this 100 watt drive is equivalent to the weight of a snowflake then I am exceedingly unimpressed. If you read the fine post that is linked to, you will see that this is literally down in the level of noise that can be produced by ground loops and so on. The author is basically saying that they tried to remove even more noise sources than last time and still have not yet tracked down what is causing the extremely tiny anomalous thrust they have measured.

I am a physicist so I am well aware of just how bloody difficult it is to track down and account for every form of noise and error in experiments like this one. Or in the experiment that measured neutrinos traveling faster than the speed of light. I am often cautioning my friends to not get too excited about weak experimental results like this that contradict foundational physical theories. I also cautioned people to not get too excited about the so-called "face on Mars" for the same reasons. Lots of fascinating things are seen in weak signals that are close to the experimental noise floor.

In addition, I have not seen any reasonable theoretical explanation for the anomalous force that is purported to power the EM drive. There is certainly no relationship between the purported physics of an EM drive and the actual physics of a ring laser gyroscope. Nor have I seen any reasonable theoretical explanation for why the thrust should scale as a large power of the input energy. Yet many people here who ignore the experimental challenges of measuring the weight of a snowflake on top of the forces acting on an apparatus dissipating 100 watts of RF energy seem to blithely accept these remarkable and, AFAIK unfounded, theoretical claims as gospel truth.