I don’t think it’s its “propellant” that is what breaks laws, as a Crookes radiometer doesn’t have propellant, but used reflected, and absorbed, photons, as I recall.
The Crookes radiometer doesn’t defy Laws of Physics.
A magnet does the same thing. An electromagnet is very similar.
What they are saying is this creates thrust with an electric field, without magnetism.
We know that can be done as well.
It does not violate conservation of energy any more than a magnet violates conservation of energy.
Let us see it use thrust to translate distance or to gain gravitational energy. It should require energy input to do that.
‘defy the known laws of physics’ = the pre-emptive strike to call it a hoax eventually. Funny, I just watched a video of the US Patents office manipulation of whose patent is confiscated by the government for the purpose of national security (and economy) - Truman signed into law in 1951
Photons, while massless, have momentum, and are absorbed or reflected in different proportions on the light and dark sides of the Crookes radiometer. This difference leads to a net torque on the radiometer, causing it to spin.