Laser Ranging Retroreflector

Description

The Laser Ranging Retroreflector Experiment (LRRR), part of the ALSEP package, was a corner reflector for laser ranging from earth. The ranging data obtained included information on lunar motion, lunar librations, and earth rotation. The LRRR experiment consisted of a folded panel structure incorporating 300 individual fused-silica optical corner reflectors, a simple alignment/leveling device, and an aim-handle mechanism. The Lunar Roving Vehicle (LRV) was used to carry the LRRR to the Hadley rill site. The LRRR became passive after deployment. A camera (60-mm lens) was used to photograph the experiment. The LRRR could be used indefinitely and provided data that, when used in conjunction with data from the Apollo 11 and 14 LRRR experiments, permited more refined distance measurements than were previously available. Now that smaller telescopes can be used, the experiment is providing greater quantities of more accurate data.