From the article: Consider the challenge of defending vast territories against cruise missiles. Conventional systems, like Patriot PAC-3 and NASAMS batteries,

From the article: Consider the challenge of defending vast territories against cruise missiles. Conventional systems, like Patriot PAC-3 and NASAMS batteries, typically cost millions of dollars per installation. So we asked ourselves a simple question: What if we could create a forcefield of low-cost drones to intercept cruise missiles worth millions? The concept seemed absurd at first, even to our team—the overmatch appeared too extreme. But we stripped the problem again to its fundamentals. Cruise missiles are fast, but they follow predictable flight paths. If we could accurately determine that flight path using two ground-based IR passive sensors (what we called Wide-Area Infrared System for Persistent Surveillance, or WISPs), we wouldn’t need expensive targeting systems on the interceptor itself. We modified our Anvil drone to carry no sensors at all—the drone would simply position itself in the projected path of the incoming missile, aligning with where the missile would pierce our virtual “force field.” Despite the initial skepticism, we demonstrated the concept successfully, destroying a target that could fly an order of magnitude faster than our interceptor.