In light of recent news that the U.S. shot down a Chinese surveillance balloon, Cornell Law professor Michael C. Dorf explains the differences between spying by ballon and spying by satellite and explores some of the murky legal areas with respect to sovereign airspace, outer space, and military uses of both. Professor Dorf points out that modern satellites can capture remarkably clear images of Earthbound sites, but a comparably equipped surveillance balloon, in virtue of being ten or more times closer to the Earth’s surface, can necessarily capture even greater detail.