Of the above, solar is the easiest to find with current
data, such as from the LRO, and there is an obvious place
to look for solar arrays. At the north and south poles, there
are regions that are in near-perpetual sunlight, usually
very close to permanently-shadowed craters that could be
used to hold instruments that require very low temperatures,
such as infrared telescopes. Thus, looking at highresolution
images of these areas should reveal whether or
not there are alien solar arrays installed. However, there is
very good high-resolution coverage of the lunar poles
thanks to the LRO NAC camera, and no obvious solar
arrays have been found so far.