Lunar Laser Ranging Example
Safety Warnings
Warning: Class IIIa Laser Hazard
Warning: Protective Eyewear Required
Purpose
Demonstrates retroreflection using a corner cube reflector — the same technology deployed on the Moon by Apollo astronauts. Students see that the reflected beam returns to the source regardless of the cube's orientation, and learn how this enables centimeter-precision Earth-Moon distance measurements.
Figure 1:
Setup with laser pointer on ring stand aimed at foam block target. The corner cube retroreflector (wrapped in foam, secured with hose clamp) is ready to be held in the beam path.
Figure 2:
Corner cube held in the beam path retroreflects the laser back onto the foam block, producing a bright green spot near the laser source.
Figure 3:
With the corner cube tilted to a different angle, the retroreflected beam still returns to the foam block target. Faint front-surface reflections scatter elsewhere.
Equipment
- 1