Fossil fuels are, by their very nature, finite resources. There are, however, numerous renewable energy sources that should be taken advantage of. One of the most abundant is also the most difficult to produce on Earth-solar energy. This book explores the feasibility of a space-based solar power satellite. The book focuses specifically on the satellite design as opposed to the end-to-end design to include the ground segment. It explores the potential orbits for such a satellite to operate from and ultimately concludes that a geostationary orbit is the only logical location for an operational orbit. This book also focuses on two segments of the spacecraft: the solar array and the power transmission payload. The solar array area was calculated using the current best theoretical solar cells and assumed a 1 GW transmission power. Finally, this book explored which transmission payload to recommend for an operational system, concluding that a laser system is the most efficient use of space and weight. The final portion of this book was to examine the business case. Based on the design in this book, space-based solar power cannot compete with fossil fuels and likely will not for the foreseeable future.