A world preparing for one interstellar mystery is now confronting the legacy of another mission built for a different kind of threat. A silent shift in our planetary-defense strategy is underway. Humanity’s first experiment in altering a celestial object now shadows the unexplained behaviors of 3I/ATLAS. And a probe launched before the public even knew Interstellar object 3I/ATLAS shows anomalous motion as ESA’s Hera mission prepares its planetary-defense rendezvous, raising urgent questions about propulsion and intent.