"The nature of the signals observed is still unclear."
They are, clearly, taking the tack of eliminating all sources of measurement error. But they haven't yet achieved that, and as yet a force remains. It seems perfectly reasonable to assume it will be attributed to measurement error, but that is not yet the case:
" Next steps include better magnetic shielding.... We believe that this is a good education project to track down measurement errors..."
NASA would have had the means to eliminate most of those sources of errors. I wouldn't call these measurement errors though -> the measurement is fine - your setup is the source of error.
But they decided not to follow such a line of research.
And yes, they are right "We believe that this is a good education project to track down measurement errors".
The measurement error being the "thrust" that is due to your experimental setup.
But let them waste some more money, time and reputation and build this in space so they can find out it does not actually work.
> NASA would have had the means to eliminate most of those sources of errors.
Yes. NASA as a whole yes. One group researching something that may or may not bear fruit no.
So it's natural they try to eliminate easier errors first. But (as an example) it's one thing to have a good vacuum, another one to have an excellent vacuum for testing. So first you test on the good vacuum.
Yes i did, usually i just let certain topics pass by me and never comment here.
RF-cavities though are the very core to my line of research, so my acceptance for bs is very low in this regard.
If one wants to convince me of a thrust effect: build a prototype where the power source (a battery for example) and the RF-source are strapped onto the cavity, put the whole setup in a vacuum of your choice (i heard NASA has very nice and !large! facilities) and show me a sustained increase in impulse (just let it rotate for a while)
Okay, but they aren't trying to convince you yet.
They're trying to convince themselves that it's worth spending the resources you describe.
> To definitively rule out any residual concerns about thermal error sources, future test campaigns could employ a test apparatus capable of measuring small torques over much larger angular displacements. For example, a Cavendish balance approach properly designed to allow very large rotation angles such as 90, 180, or even 360 deg will not be susceptible to this type of thermal false positive.