Apoapsis and periapsis: the high point and the low point

Orbit 101 · Oct 8, 2026 · 8m

This is Orbital Radio. Out here, you’re never alone.

Here’s a riddle. Your ship is in orbit, engines off. Nothing’s pushing it. Nothing’s touching it. Up above the air, there’s nothing to slow it down. And yet, unless your orbit is a perfect circle, the speed on the navball won’t sit still. For half of every lap it climbs. For the other half it sinks. So who’s working the throttle?

Nobody. Your ship is rolling around a bowl. And every bowl has a top and a bottom.

Today on Orbital Radio, the high point and the low point. By the end of this show, you’ll know why nearly every orbit has one of…