The Moon Engine was a device used in the animated series The New Adventures of He-Man.
The Moon Engine was a device created by the brain-enhanced Evil Mutants, most notiably Staghorn. When placed on the center of Nordor's rotation, it would push it out of it's orbit, leaving it's mass to crush the shield around Primus.
He-Man managed to reverse the effects of the machine and return Nordor to it's original orbit around Denebria in the nick of time.