Echoes from the Moon

TL;DR

This paper demonstrates how high school students can accurately measure the Earth-Moon distance using radio communication delays, revealing lunar orbital eccentricity through accessible software tools.

Contribution

It introduces a simple, educational method for measuring lunar distance and orbital eccentricity using open-source software and radio echo timing.

Findings

Distance measured with three-digit accuracy

Detection of lunar orbital eccentricity

Educational approach for precise astronomical measurements

Abstract

We report on a determination of the Earth-Moon distance performed by students of an Italian high school, based on measurements of the time delay of the "echo" in the radio communications between Nasa mission control in Houston and the Apollo astronauts on the lunar surface. By using an open-source audio-editing software, the distance can be determined with three digits accuracy, allowing to detect the effect due to the eccentricity of the orbit of the Moon.