With the ever-increasing demand for power, shortage of natural resources, and increasing concerns about the pollution of the environment, renewable energy sources are becoming more popular. Unfortunately, not all locations on Earth have the capacity to host new renewable power plants. Some of these areas coincide with regions where the power demand is likely to increase in the future. This is of concern as this additional power demand may be satisfied by traditional, non-sustainable power plants. But it also creates a chance to introduce a new renewable energy source: a Solar Power Satellite. This book reviews previous work done in the field of Solar Power Satellites, and analyses important factors that need to be taken into account when designing such a Space-Based Solar Power system. Then a systematic system-level study of a Solar Power Satellite mission is conducted. Finally, a potential design of a demonstration mission that could be implemented using readily-available technology as well as scaled up to a full-fledged system is proposed.