The REAL obstacle to SPSS

diplomatic, and international. Any solar power satellite system that
can deliver power reliably to the ground can also deliver power
reliably to a "target", i.e. it can be used as a weapon. Please do not repeat this oft-repeated but thoroughly-wrong canard. The microwave beam from an SPS would have zero usefulness as a weapon. For one thing, the power density per unit area is far too low (at or below the level of sunlight). For another, as a weapon it would be one requiring the active cooperation of the target. (I'm referring to the rectenna pilot beam, which is the only thing that makes the phased-array transmission possible.)