Any maths suggesting otherwise is wrong.
This should be easy to prove if it's true. Please tell us how math can be manipulated
I do it on my web site. It is assumed (by e.g. tattoed clowns in porno shirts at ESA) that the smaller, moving object - the space craft - is affected by the bigger, moving object by gravity forces interaction and
kicked off at increased speed in a new direction. The assumption is wrong. The gravity force of the bigger object will simply
attract the smaller object, so it crashes on the bigger object - like, e.g. any meteorite approaching planet Earth. The latter happens 100's of times every day/night.
Any maths asuming that the direction of the smaller object
is not changed prior encounter with the bigger object and is kicked away is false. Only sect members believing in
kicks assume otherwise - so they can collect salaries, etc.