Sky Coverage and Shadow
Raoul,
Go stand in the corner with a Dunce's hat on:-
If you locate an observatory in permanent shadow in a crater the Lunar North (or South) pole, this means that the Sun will never rise above the crater rim, as seen from the telescope itself - right?
This means that THE PLANE OF THE ECLIPTIC will never be visible to the telescope.
Ergo, it will be impossible to look at the orbital plane of 99.9% of all solar-system material.
It will also take two bases - one North, one South - to cover that 0.1%.
In contrast, a space-based facility can cover 99.9% or more of all the sky, from one 'scope. (and it's cheaper)
QED