Gerard K. O'Neill (1927-1992), a particle physicist who spent most of his career at Princeton University, was the driving force behind the first serious space colony design study. Conducted in 1975, this study took the form of a ten-week program held jointly at the National Aeronautics and Space Administration (NASA) Ames Research Center and at Stanford University, outside San Francisco, California. NASA and the American Society for Engineering Education sponsored the program. The program's work laid out the basic requirements for large-scale human settlement of the solar system. As technical director, O'Neill guided the study towards its basic conclusion that the best way to begin the human colonization of space was to build a large space colony at L-5, with the colony being dedicated to using lunar materiel to build a series of solar power satellites to beam electricity down to an energy-hungry...