re: Uh, yeah Chris. I'm gonna do that....
Thanks Geoff, but I don't believe a statement like "There seems to be no measurable degradation in their performance." mean anything.
The laser beam passes twice thru the Earth's atmosphere which acts like a lens that expanse the beam by miles meaning only a few photons return to be sensed. This is how it has always operated. But we have better tools to use to sense and better lasers with better wavelengths to use. Unless someone has actually checked the operations for a degrading I don't think they would see any. As long as they get readings everything is fine.