I’ve not devoted much cogitation to the EM drive, mostly because it just strikes me as bunk. There has recently been some renewed interest due to the appearance of a peer reviewed paper that seems to back up some of the claims… but when the thrust level for 100 watts is measured in *micro* newtons, I just can’t scrape up much interest. Especially when the guy behind the idea was claiming that it would be able to power flying cars (capable of VTOL) and space launch boosters, requiring an improvement in T/W on the order of ten to a hundred MILLION times. And, oh yeah, overturning the laws of thermodynamics. Whenever something claims to do that, I tend to tune out.
If the EM drive actually works (and it seems more likely that it works like a radiometer), then it’s kinda like everything else that has ever been touted as actual functioning magic. Yeah, sure, great, you can bend that spoon with your mind. But look at the effort required; using magic, you’re doing it the hard way.
Here is a good if lengthy explanation of why the EM drive most likely doesn’t work, and even if it did, why it sucks: