Figure 6-32 RIVUXG Lunar Ranging Beams of laser light are fired through three telescopes at the Observatoire de la Côte d’Azur, France. The light is then reflected back by the corner reflectors placed on the Moon by Apollo astronauts. From the time it takes the light to reach the Moon and return to Earth, astronomers can determine the distance to the Moon to within a few millimeters.