Since the opening of the space age nearly 50 years ago, the U.S. government has spent close to $1 trillion on space-related activities. Although by no means the largest public expenditure over that period-it is easily dwarfed by national defense, social security, and countless other federal programs-it is still, by any measure, an enormous amount of money. It therefore seems perfectly reasonable to ask: what has the American taxpayer gotten in return for this rather large investment? This book will examine the changing views of NASA's mission(s) held by government officials over the years....