Hadrian's Dome

Protecting Earth from a planet-killing impactor is not science fiction. DART proved kinetic deflection works. What stands in the way is sensing coverage, decision authority, and a legal framework that never anticipated the question. The United States currently spends more every year on military marching bands than it does on planetary defense. Hadrian's Dome sets out what a real architecture would cost, who would authorize its use, and which provisions of the Outer Space Treaty stand in the way.