Comment by perihelions

I think this could be life-changing for cities at high latitudes. You wouldn't even need that much: simple twilight-levels of illumination would a long way towards helping people's psychology and quality-of-life in winter.

A key thing that would make this easier than it'd naively seem, is that human perception of ambient light levels (like many kinds of human sense) is sort-of logarithmic. Twilight is just 10^{-5} – 10^{-4} the illumination level of sunlight,

https://www.engineeringtoolbox.com/light-level-rooms-d_708.h...

(That is, to my naive first take: a 100 x 100-meter collector in orbit intercepts enough sunlight to bring a 10km x 10km city to bright twilit level).