Space operations are among the most demanding and unforgiving pursuits ever undertaken by humans and will become all the more difficult when means do not match aspirations. Will we leave the close proximity of low-Earth orbit, where astronauts have circled since 1972, and explore the solar system, charting a path for the eventual expansion of human civilisation into space? If so, how will we ensure that our exploration delivers the greatest benefit to the nation? Can we explore with reasonable assurances of human safety? Can the nation marshal the resources to embark on the mission? This book explores the nations important decisions on the future of human spaceflight. This book consists of public documents which have been located, gathered, combined, reformatted, and enhanced with a subject index, selectively edited and bound to provide easy access.