Emdrive explanation

Many great discoveries have happened through serendipity.

yeah and if the memedrive worked, they could have just shot it off in the direction opposite of the asteroid, decelerated, flipped around, and hit the asteroid at something percent C. This would completely vaporize the asteroid, turning it into a harmless puff of plasma by the time it hit earth.

Reactionless drives are OP

Of course if they really cared about physics, they would have used Project Orion

That blue glow is wasted energy.(Not much though)