Crossing the Threshold

<br><br><b> Ensuring a Sustainable World</b><br><br> We are on the cusp of a 21st century Age of Discovery - about the Earth about the solar system about ourselves and our place in the cosmos - with new opportunities to address age-old challenges as well as to meet emerging ones. While advancing into space is not the answer to these challenges it can be a significant and vital part of an answer providing benefits that other answers cannot. <br><br>With a thoughtful program of space activities we can ensure a sustainable world with abundant energy and resources a high standard of living and unprecedented opportunity for all. However to become a widely held vision that we must pursue now rather than just interesting ideas for some distant time we need to see space as integral to addressing societal issues. This book shows a way to do that. <br><br> There are abundant opportunities in space but the only way to utilize them is to go there. As our ancestors crossed thresholds to inhabit the Earth we can cross the threshold to become a space-faring civilization and realize the benefits of those efforts. Space is only 100 km (62 miles) away you just need to look up.<br><br>What people are saying:<br><br>Crossing the Threshold is a carefully considered insightful narrative that should interest anyone and everyone who cares about the future of spaceflight. - Homer Hickam author of Rocket Boys/October Sky<br><br>Crossing the Threshold is a NASA veteran's thoughtful and considered look at the value of space travel and exploration not only for satisfying humanity's seemingly unquenchable thirst for adventure and knowledge but also for preparing and positioning us technically to begin to solve some of the greatest problems facing us on Earth. - Henry Petroski Aleksandar S. Vesic Professor of Civil Engineering and Professor of History Duke University author of The Essential Engineer: Why Science Alone Will Not Solve Our Global Problems<br><br> Crossing the Threshold is very impressive for the range of ideas and technical specifics. - Felix Godwin author of The Exploration of the Solar System.