Book excerpt: Throughout history, humans have explored new places, making both good and bad moral decisions along the way. As humanity proceeds to explore space, it is important that we learn from the successes and not repeat the mistakes of the past. This book provides the first comprehensive introduction to ethics as it applies to space exploration and use. It examines real-world case studies that exemplify the ethical challenges we face in exploring beyond Earth: space debris, militarization in space, hazardous asteroids, planetary protection, the search for extraterrestrial life, commercial and private sector activities in space, space settlements, very long duration missions, and planetary-scale interventions. Major themes include human health, environmental concerns, safety and risk, governance and decision-making, and opportunities and challenges of multidisciplinary and international contexts. Ideal for classroom use and beyond, the book provides ways of thinking that will help students, academics and policymakers examine the full range of ethical decisions on questions related to space exploration.