For decades, scientists have dismissed the idea of reactionless propulsion—the concept of generating thrust without expelling propellant—as a fantasy that defies the laws of physics.

But the not-based-in-physics dream of a propellant-less machine ... For years, their devices produced negligible thrust, but ...

The space shuttle accelerates upwards from its launch pad. The thrust \(T\) from the rocket engines is greater than the weight \(W\) of the rocket system. Since force \(T\) is greater than the ...