> You'd have to supply the energy externally (i.e. some sort of beam propulsion), but getting any significant fraction of g out of such a system (with human-siz

> You'd have to supply the energy externally (i.e. some sort of beam propulsion), but getting any significant fraction of g out of such a system (with human-sized payloads) seems unlikely within the next centuries, especially as the distance increases. Or some form of ram scope, plenty of H everywhere, but those also have the issue of you collecting things while going at relativistic speeds.