Mining the sky

What would it be like if entrepreneurs could literally "mine the sky" to solve Earth's three major fulfillment problems: energy, mineral resources, and food? That is the engaging premise of John S. Lewis's visionary new book. What if we could chemically break down the atmosphere of Mars for substances that can be used as spacecraft propellants; hollow out asteroids to transform them into livable habitats for billions of space-bound homesteaders; mine the asteroids for precious metals to be used in space construction projects; milk the comets and the moons of Mars for their vast supplies of…