Measuring The Earth With Big Metal Balls

Beyond bouncing communications, Echo-1 and Echo-2 helped scientists do something even more ambitious: measure the Earth itself. By tracking how signals reflected off Echo as it moved across the sky, researchers could refine calculations of orbital mechanics, map distances more accurately, and improve understanding of Earth’s shape and size. It was one of the earliest steps toward turning space into a tool for precision Earth measurement, using nothing but a giant balloon and a bit of radio physics.