Force projector

Force projectors consist in a molecule-thin sheet of crystalline material that experiences a reactionless force normal to its surface when a voltage is applied across it. The higher the voltage, the stronger the force.

Force projectors convert surrounding oxygen to ozone when running, which is why very large projectors that run continuously like you see in spacecraft cannot be used in atmosphere. The projector plates on the paws of large mechs are the largest practical terrestrial application for them.