Great ellipse

A great ellipse is like a giant circle that goes around the Earth. It helps scientists and engineers figure out where they need to send things like satellites and spaceships so they can travel through space correctly. Imagine drawing a really big circle around the earth, but it's not a perfect circle, it's a bit squished. That squished shape helps scientists make calculations and plan space missions. Think of it like the path a race car follows around a racetrack - the car needs to stay on the track and follow the path, just like satellites and spaceships need to follow the great ellipse so they don't get lost in space.