Re: General Relativity
General relativity describes spacetime curvature near a massive object. So, yeah, "translation" can occur without any propellent whatsoever. But if you're interested in propellant-free propulsion, there is a thing called an electrodynamic tether which works near any planet with a magnetic field, eg. Earth or Jupiter. A satellite equipped with an electrodynamic tether can raise or lower its orbit without expending any propellent, just good 'ol solar power. Of course orbital changes take months with the few measley watts that solar panels can provide.