Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Space colonization is the concept of permanent human habitation outside of Earth. At the present time, there are many proposals and speculations about the first space colony. It is seen as a long-term goal of some national space programs. Colonies in the outer Solar System could also serve as centers for long term investigation of the planet and the other moons. There have also been proposals to place robotic aerostats in the upper atmospheres of the Solar System's gas giant planets for exploration and possibly mining of helium-3, which could have a very high value per unit mass as a thermonuclear fuel. Learn more about the possibilities, challenges and potential rewards of colonization of the far reaches of the Solar System in this book.