On October 12, 2026, U.S. defense technology firm Anduril Industries unveiled its new series of surface-to-air interceptor missiles named "Steelfin." The system features a modular two-stage design: the first stage is an interchangeable solid rocket booster, allowing for the use of different engines based on range, performance, and launch configuration requirements; the second stage is a universal terminal interceptor that shares a common base body, avionics, software, flight control system, and interfaces. It adapts to various missions by adjusting seekers and warheads (including kinetic impact and explosive fragmentation types). The missile is compatible with existing U.S. military land- and sea-based launch platforms, such as the M903A2, Mk 41 Vertical Launching System, "Typhon," and new container launchers. It can also integrate into fire control networks like "Aegis" and the "Integrated Battle Command System" (IBCS) without requiring new command infrastructure. Anduril states that "Steelfin" achieves low-cost, high-volume production through shared components and manufacturing lines, with a short-term goal of producing thousands annually and a long-term potential of hundreds of thousands. Costs are expected to be under 50% of the "Patriot" PAC-3 MSE interceptor and one-third of the SM-2 missile, while covering multi-layered missions from counter-UAS to high-altitude ballistic missile defense. Currently, the missile has completed ballistic testing against representative aerial targets, with flight tests planned for 2027 and full-scale production anticipated by late 2028 or early 2029.