Angular Momentum - Physics 101 / AP Physics 1 Review with Dianna Cowern

I remember many years ago when a satellite did a Mars fly-by for a gravity-assist.  Because of conservation of (something), energy had to be transmitted from the planet to the tiny satellite.  Considering the mass of the planet vs. the mass of the satellite with their respective motion through the solar system, somebody actually calculated how much the day and the year of Mars was lengthened by transferring that energy to the satellite.  Of course, it was a tiny, tiny fraction of a millisecond.  But I remember being struck by the fact that such a calculation was even possible.