That is a terrible book that starts with the premise that it isn’t possible or desirable. d then arranges its arguments to
come to that conclusion. But it turns out that making solar cells on the mean is feasible.
I felt they had some very good points, though, and I don't see any progress on the major blockers to any sort of large scale extra-planetary colonization. I hadn't considered the issues with procreation discussed in the book, for example--that's kind of a huge issue if we want to have any sort of self-sustaining population outside of this earth!