I briefly looked at this a while ago. The short answer is no, space mirrors (or lenses which focus light away and need less fuel to maintain position) are not a

I briefly looked at this a while ago. The short answer is no, space mirrors (or lenses which focus light away and need less fuel to maintain position) are not a viable solution launched from earth. We'd be better off reducing emissions. If you want to do large scale construction in space you need to get material from outside of a gravity well.