How did NASA accurately measure the distance between earth and the moon?

NASA accurately measured the distance between the Earth and the Moon using laser ranging techniques. By bouncing laser beams off retroreflectors left on the Moon's surface by the Apollo missions, scientists could measure the time it took for the light to travel to the Moon and back. This precise timing, combined with the speed of light, allowed them to calculate the exact distance between the two bodies. The measurements have been refined over the years, providing highly accurate data on the Earth-Moon distance.