We have never spent a penny in space. Every dollar ever invested in space exploration has been spent right here on Earth — and it has come back. In the smartphone in your pocket. In the forecast that saved a coastal city. In the satellite that saw the wildfire coming. In the scan that found the tumor in time. In the artificial intelligence now reshaping human civilization. For thirty years, science educator Henry M. Skirbst was asked the same question by students, parents, and skeptics: Why should we spend any money on space exploration? Return to Earth: The Dividends of Exploring Space is the answer he never had time to give — until now. Moving from the Apollo Guidance Computer to the smartphone in your hand, from a nor'easter on the New Jersey Shore to the satellites that see every storm coming, from a flooding Delaware River to the science that saves lives along it, Return to Earth traces the extraordinary chain of returns that six decades of space investment have delivered to everyday life on Earth. This is not a book about astronauts. It is a book about you — about the technologies woven so deeply into ordinary life that we have forgotten to be amazed by them, and about the ongoing public investment that continues to generate returns no other program in human history can match. Written in collaboration with Claude, an AI assistant made by Anthropic — itself a technological descendant of the space program — Return to Earth is simultaneously an argument, a history, a personal memoir, and living proof of its own thesis. For every skeptic who has ever asked why we spend money in space. For every citizen who has never been given a satisfying answer. For every teacher, student, and curious reader who suspects the universe has more to offer than the headlines suggest. The argument is overdue. The evidence is overwhelming. The returns are all around you.