A simple cuestion about Island 3

> Yes, but we still end up with a mechanical connection to a rotating > body and that introduces drag on the mirror for which we must correct. True, but with reasonably well designed bearings, those forces would be relatively small. Between the technical challenges of a small electric motor making up frictional losses, and keeping mirrors miles across and under multiple G loads of centrifugal force from sagging even slightly anywhere across their surfaces, the former is the easier challenge.