Hey there space enthousiast,

Hopefully I am posting in the right subforum, my apologies if it isn't.

Ive got an orbital mechanics question:

Cassini used the gravity assist of 2 Venus flyby's to get the right orbit to have an encounter with Saturn.

If I understand it correctly Cassini Hohman transferd to Venus, so decreasing its orbit (relative to the sun), afterwards increasing it's ap twice on the Venus flyby's. (Is this correct?).

My question is: how come Venus was the most efficient planet to use for its gravity assist? First decreasing your speed relative to the sun (lowering ep), to later increase it, seems counter intuative. Why is it not more efficient to use mars for example? So far I havent been able to clear this up with my limited googling skills. Can someone explain this to me?

Would be very much appreciated.

Thanks!