I have a continuing suggestion. Put a ground robot station
on the Moon's surface below L2. The robots could be made
more fault tolerant there, while they construct ultra-light
solar sails. I am talking about multi-Kilometer sized sails.

At L2 there is a vertical climb from ground, no Moon circling.

I believe that robots with a ground construction base frame
would be able to recover from faults easier than free fall.
Free-fall sail oscillations would not exist also.