That is wrong. Cassini's apogee (aposelene) is inside the orbit of Iapetus, which is 3.5m km from Saturn. Cassini does not fly by Iapetus in its tours; the or

That is wrong. Cassini's apogee (aposelene) is inside the orbit of Iapetus, which is 3.5m km from Saturn. Cassini does not fly by Iapetus in its tours; the orbit was adjusted to do so once but will not happen again. The graphic is representing the distance of Saturn at its closest point to Earth (as it does with Mars and Venus), but the distance of Cassini at its farthest point from Earth. The latter is larger by the diameter of Earth's orbit which is your 300m km difference.