We just got another EmDrive question, https://physics.stackexchange.com/questions/185380/emdrive-in-relation-to-newest-nasa-article-does-it-extract-energy-out-of-the-q, and much as you would expect it swiftly got closed and an OP probably went away feeling fairly upset. I feel we get enough EmDrive questions that this is something we ought to handle with more care and specificity.
Posts on the subject seem to be along several different lines:
- "could it possibly work?"
- "how do its proponents claim it works?"
- "do those claims have merit?"
- "if not, how do they fail?
- "assuming that it works, how does it do so?"
If you look at them like that, they are not really all that bad. The problem is that posters tend to pretty much always ask that final question, and that tips the question definitely into the territory discouraged by our non-mainstream physics guidelines. The third question is on the boundary (we are not here to evaluate pet theories) but if the question is appropriately phrased, for something this recurrent, I feel we're better off showing a bit more flexibility and allowing a few canonical questions about this.
So, what I propose is separating these different components, which will help us better address the ones that we can, and cleanly close the ones that we can't. I have therefore asked this question:
and provided a basic answer. (I do not think, though, that there are any more worthwhile references. The ones I did find are singularly thin on the theory even by my low prior expectations. However, if you can find more references, by all means add them in.) This addresses question (2) above. With this in place, questions asking what the claims are can be referred there. If they don't find the resources there sufficient - i.e. if they don't find this community's response to be thorough enough in helping them scour the web for references - well, tough luck. They can look for their own and add them there, or they can offer a bounty on it to try and draw attention to it.
does a very good job at addressing (1). In the absence of multiple peer-reviewed tests performed in vacuum and published in reputable journals, question (5) is very clearly off-topic. Questions (3) and (4) can be evaluated on a case-by-case basis but are almost certainly off-topic as well.