You have some excellent questions, Virginia. I had just assumed that (because of the G's) this would only be able to be used for unmanned exploration. But if we could have something like this, combined with Mars Rover-type land vehicles (for solid planets) or ruggedized exploratory drones (for gaseous ones), imagine the level of details we could get about the planets.
Regarding going too far from the sun -- my understanding is that the vast majority of fuel now is spent getting out of earth's gravity well. Once a vehicle leaves there, Newton's laws, possibly combined with a small engine and a minor amount of fuel, should take the vehicle far.
Again, assuming that this isn't too good to be true.
Joy,
Lynn
