I just spent a bit of time reading a thread about a flight mode using a simplistic gravity model, which I agree with fridger, you just cant do it.
If I remember my physics classes, and I was a history major, so dont get mad if I get something wrong, isn't the following true:
Gravity, as experienced by an object in space, and on earth for that matter, is a combination of forces from every other object in the universe, however slight it may be.
I mean, our solar system is in orbit around the galactic core due to the gravity well of the mass in the galactic core. Our galaxy is moving due to the gravitational interaction with other galaxies.
And a simplistic version of gravity for a fly by of jupiter is rather inappropriate considering that is probably one of the densest gravitational fields in our solar system.
