Anduril Steelfin

History

Anduril Industries unveiled the Steelfin family of surface-to-air interceptor missiles on 12 October 2026. The company stated it has been developing the system for several years with investment from multiple customers and has completed ballistic testing using representative air vehicles. Flight testing of Steelfin variants is planned to begin in 2027. Anduril has not previously developed or produced a surface-to-air missile, though its Roadrunner system provides experience in countering aerial threats including loitering munitions.

Anduril is planning near-term production on the order of several thousand missiles annually, using a shared production base across variants with capacity designed to expand or shift according to demand. Full-rate production is targeted for late 2028 or early 2029. The company stated it is working with a number of customers to field the system.

Design

Steelfin uses a two-stage architecture comprising a first-stage solid-rocket booster, which determines range and flight characteristics, and a second-stage terminal interceptor. All variants share a common baseline airframe, avionics, software, flight control system, and interfaces. The modular, open-system design allows different rocket motors, seekers, and terminal-stage components to be swapped to tailor configurations to specific missions. Both hit-to-kill and blast-fragmentation terminal-stage interceptors are planned for the family.

Anduril is looking at 10-inch, 18-inch, and 21-inch boosters, as well as quad-pack and dual-pack configurations for the Mk 41 Vertical Launch System. The system is designed for compatibility with existing launch infrastructure including the M903A2 launcher, Mk 41 VLS, Typhon, and emerging containerized launchers, and with fire-control systems including AEGIS and the Army’s Integrated Battle Command System (IBCS). The family is intended to address cruise missiles, ballistic missiles, and hypersonic missiles across a mission spectrum ranging from point defense and lower-tier integrated air and missile defense to upper-tier ballistic missile defense.

The stated speed range is supersonic to hypersonic depending on booster configuration, with engagement range also configuration-dependent. Anduril has not disclosed detailed performance specifications or engagement envelopes. In cost positioning stated by Steve Milano, the company’s lead for Air Dominance and Strike, the PAC-3-type configuration is expected to provide approximately 80 percent of PAC-3 capability at less than half the cost of the PAC-3 MSE; a higher-performance configuration is described as capable of performing the full THAAD mission at a fraction of its cost; and a lower-cost variant is positioned to provide greater than 80 percent of the capability of the SM-2 Block IIIC interceptor at approximately one-third its cost. Reference unit prices cited for comparison are approximately $15.5 million (THAAD), $5.3 million (PAC-3 MSE), and $2.5 million (SM-2 Block IIIC).