Outer space is no longer a distant frontier. It is a contested domain with immediate global consequences. Once defined by exploration and cooperation, it is now shaped by military competition, rapid technological change, environmental stress, and expanding commercial activity.This book offers an integrated account of space governance through four critical lenses: security, law, sustainability, and economics. It examines the militarisation of space and the rise of artificial intelligence, the resilience and limits of international law, the urgent challenge of space debris, and the growing influence of private actors.By weaving these perspectives together, the volume argues for comprehensive governance frameworks that move beyond fragmented solutions. It highlights how today's choices will determine whether outer space remains a shared domain for peace, innovation, and human progress or becomes a theatre of conflict and competition.