Cassini, nah it didn't it was tradition propulsion/sling-shot pellet, and as I said, as I said, its not feesable right now for mainstream travel, I.E. rocketing people around the stars, it would just take far too long that way, long term probe missions are another matter entirely, I mean there is no harm in them having a propulsion system that accelerates at about the same rate as some continents move(and for proof on that the himilayas grow at a rate of approxmately 2-3 inches per year, a result of the india sub continent slamming into asia) For a people ferry we needs something that has a conciderably high rate of acceleration