Book excerpt: A noted space expert explains the current revolution in spaceflight, where it leads, and why we need it. A new space race has begun. But the rivals in this case are not superpowers but competing entrepreneurs. These daring pioneers are creating a revolution in spaceflight that promises to transform the near future. Astronautical engineer Robert Zubrin spells out the potential of these new developments in an engrossing narrative that is visionary yet grounded by a deep understanding of the practical challenges. Fueled by the combined expertise of the old aerospace industry and the talents of Silicon Valley entrepreneurs, spaceflight is becoming cheaper. The new generation of space explorers has already achieved a major breakthrough by creating reusable rockets. Zubrin foresees more rapid innovation, including global travel from any point on Earth to another in an hour or less; orbital hotels; moon bases with incredible space observatories; human settlements on Mars, the asteroids, and the moons of the outer planets; and then, breaking all limits, pushing onward to the stars. Zubrin shows how projects that sound like science fiction can actually become reality. But beyond the how, he makes an even more compelling case for why we need to do this--to increase our knowledge of the universe, to make unforeseen discoveries on new frontiers, to harness the natural resources of other planets, to safeguard Earth from stray asteroids, to ensure the future of humanity by expanding beyond its home base, and to protect us from being catastrophically set against each other by the false belief that there isn't enough for all.