http://www.space.com/scienceastronomy/lost-soviet-reflector-found-on-moon-100427.html
"Near full moon, the strength of the returning light decreases by a factor of ten," Murphy said.
"We need to understand what is causing this if we are contemplating putting additional scientific equipment on the moon.
Finding the Lunokhod 1 reflector will add important clues to this study."
I didn't know this !
It is a little know fact, but all the manned lunar landings did happen soon after local sunrise so we have no direct check upon the conditions later in the moon "day". Just as an example, consider the electrical interaction between moon dust and solar wind charged particles. Maybe loss of reflectivity is due to dust partly covering the reflector at local noon when more excited by solar flux.
Isn't it great that you can make science out of 40 years old equipment?
Bye!!!
:)