In the few seconds the photons take to get to the moon and back, the earth has moved enough on its axis that the reflected beam from a perfect retroreflector is not gonna hit the protagonist.
The retroreflectors for the Apollo missions were deliberately spoiled so they return six slightly offset beams, angled such that photons from one of them will go back near enough to the source.
- Citation needed. And did you mean the inverse square law? 188.8.131.52 07:37, 31 October 2014 (UTC)