We live in the Golden Age of space exploration. Humanity's achievements include the continued operation of the International Space Station, rapid advancements in reusable rockets, and soon, a return to the Moon. Within our lifetime, we might have human outposts on the lunar surface and flags flying on the plains of Mars. These strides are not just about reaching new frontiers. They have profound implications for life on Earth. The data from climate satellites overhead, innovative materials and recycling systems designed for space habitats, and emerging spacebased energy solutions are essential to addressing Earth's conservation challenges. Space enables the understanding of Earth as much as Earth enables the exploration of space. This bright tomorrow is not assured, however. Space junk, international conflicts and fiscal calamities loom as threats to all that might be accomplished. For the human adventure to continue beyond the Earth's atmosphere, the time is now to reconsider the nature of sustainability. Space in Our Hands is a comprehensive exploration of critical and sometimes challenging aspects of our space endeavours, including: the evolution of energy technologies, the feasibility of permanent lunar settlements, the potential for extraterrestrial mining, and the challenges posed by space debris, all within the context of current legal frameworks and international agreements. Leading experts in each field offer insights on the deep connection between Earth and space, underscoring that sustainability - whether on our planet or in the cosmos - is integral to success and vital to our future. AUTHOR: David W. Brown is an American author whose work appears regularly in "The New Yorker", "The New York Times", and "Scientific American". His latest book, The Mission, was published in 2021 by Custom House.