A scan of a black and white PR glossy sold on ebay depicting a Boeing concept for a solar power satellite from the 1970’s. Most SPS concept were for Manhattan-sized slabs of aluminum trusswork, holding vast fields of photovoltaic cells. This design, though, was different in that it was a Manhattan-sized collection of vast reflectors concentrating sunlight onto relatively small targets. There a working fluid would be super-heated and the resulting high pressure gas blown through turbogenerators. The gas would be cooled and condensed in the radiators. Note that the artist took some liberties with the orientation: a setup like this would only work if the reflectors were reasonably precisely aligned with the sun. That would only occur when the shadow of the solar collector at the focal point fell onto the center of the concentrating mirror assembly; the radiators would cast almost no shadow, just a razor-thin line bisecting the mirrors.
