In Local expansion measured, near zero via Lunar Ranging - what about deep space probes? I used images of the retro-reflector arrays that were left on the moon by Apollo 11, 14, and 15. The Lunar Ranging Retro Reflectors (LRRRs) are there for Lunar Laser Ranging.
The arrays and their supporting structures appear to be significantly different from each other, suggesting design improvements or slight repurposing. Looking closer at the images, I see auxiliary structures on each one. What are all these things and how were they used?
Some appear to be sun-dial-like (for want of a magnetic field), and at least one looks a little like a bubble level with a vertical tab next to it. I'm pretty sure B is not there to blow moon dust off of the array :) - it could maybe be an infrared thermometer, but was there telemetry? See Lunar Laser Ranging Tests of the Equivalence Principle, page 8 for a discussion of the relevance of the widely cycling temperature of the array - for Equivalence Principe (EP) experiments it's necessary to measure throughout the entire 27 day long lunar day-night cycle.
Only one shows the faces of the reflectors directly, and they appear to be corner-cubes, which, individually at least, don't necessarily have to be pointed very accurately at all in every-day use, although I imagine an antireflection coating might have a cone of best performance.
Since the orientation of the arrays is always changing due to Libration - albeit in a very well determined way - if careful orientation was necessary, or at least careful documentation of the orientation, why?
below: Apollo 11 LRRR annotated detail, original image here (0.7°N 23.5°E)
below: Apollo 14 LRRR annotated detail, original image here (3.6°S 17.5°W)
below: Apollo 15 LRRR annotated detail, original image here (26.1°N 3.6°E)