During the past fifty years, U.S. leadership in space activities has benefited the global economy, enhanced our national security, strengthened international relationships, advanced scientific discovery and improved our way of life. Space capabilities provide the U.S. and our allies unprecedented advantages in national decision-making, military operations and homeland security. Space systems provide national security decision-makers with unfettered global access and create a decision advantage by enabling a rapid and tailored response to global challenges. Moreover, space systems are vital to monitoring strategic and military developments as well as supporting treaty monitoring and arms control verification. This book examines the United States national space policy and national security strategy.