In 1941 Isaac Asimov, the science fiction writer, published a short story called "Reason." It was a cautionary tale about robotics and artificial intelligence, but it's also remembered now for its fanciful setting: A space station that gathered solar energy to send to the planets via microwave. Ever since, space-based solar power has been an out-there idea—something with potential to change the world, if we can ever master the technology, and muster the funds, to do it.

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