Although environmental philosophy and the human exploration of space share common beginnings, scholars from either field have not given adequate attention to the possible connections between them. In this essay, we seek to spur the rapprochement and cross-fertilization of philosophy and space policy by highlighting the philosophic dimensions of space exploration, pulling together issues and authors that have had insufficient contact with one another. We do so by offering an account of three topics: planetary exploration, planetary protection and the search (...) for extraterrestrial life, and terraforming. The resulting synthesis seeks to change our thinking about earthbound environmental ethics as it considers the philosophical dimensions of space exploration, and introduces the possible benefits of a humanities-oriented approach to space policy. (shrink)