Yes, there was criticism in the article, suggesting evaporation as the source of the thurst. However, it was (together with all criticisms) removed/censored by POV pushing editors. No control for mass was done in either experiment, and evaporation of order of less than microgram per second could easily explain the effect (especially in the NASA case); even more so, if there is some moisture. What you are essentially doing, is microwaving the interior of a cone, and - surprise surprise - there is a small force in the opposite direction. Then you turn off the heating, but your interior is still at higher temperature, measure it again, and there is still a force - yet smaller. Nothing to do with exotic physics, everything to do with experimental error due to unforeseen effect of evaporation, i.e. ablation (though some moisture might play an effect, especially if there are parts other than metal; this is, in my opinion, the most likely explanation - EM radiation cannot cause such effect at these power/force ratios (that part was also removed from the article, though all was sourced). So, if there is no some weird effect (and QED effects, virtual plasma included, boil down to EM radiation reaction, there is no violation of impulse conservation there, so that is excluded too), it should be reaction from some loss of mass - and evaporation is an obvious source. However, they did not check for that. Also, some of experiments were done in atmosphere (at atmospheric pressure, even in chamber?! according to brief paper), so other possibility is interaction with heated air. However, in vacuum, ablation seems to be most likely explanation. Why all this sourced material and all criticism was removed, beats me. 213.198.221.171