Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets Book

John S. Lewis is a professor of planetary science at the University of Arizona. His expertise on the composition and chemistry of asteroids and comets really shines through in this book. The premise of the book is to explore the possibilities of a self sufficient space program. Lewis argues that with initial investment in some properly planned space missions, in contrast to the flags and footprints missions of the Apollo program, a reasonably profitable space economy can be set up. He explores the economic and technological possibilities of having a permanent base of operations on the moon beaming solar power in the form of microwaves back to the Earth. He proposes that for this to be economically feasible the majority of propellants and photovoltaic cells be manufactured using processed materials from the moons regolith. The major obstacle that this plan runs into is the lack of hydrogen on the moon; hydrogen is essential to the manufacture of water and propellants. If space missions are to be economically feasible, the book proposes that we mine near earth asteroids (NEO's). Over half the NEO's are dead comet nuclei, rich in water and other volatiles. The remaining half are rich in metals. With these resources solar cells can be manufactured and placed in geocentric earth orbit, beaming cheap solar power 24/7 to Terra. He then outlines several possibilities of how the space industry can export materials and power to the resource limited earth such as helium-3 from the moon and the atmospheres of giant planets. He argues that humanity's expansion into space, forced by overpopulation and dwindling resources, is inevitable. This book was a pure joy to read. It is well thought out and written, each chapter begins with a brief story like narrative taking place in the future, showing us various possibilities and exiting our imagination.