Anduril Unveils Steelfin: A Modular Missile Family to Slash Air Defense Costs

Key points

• Steelfin uses a two-stage design with a shared terminal interceptor and swappable boosters to cover missions from point defense to ballistic missile interception.
• Anduril claims the system will cost one-third of the current PAC-3 MSE, which is priced at approximately $5.3 million per unit.
• The company plans to achieve full-rate production by late 2028 or early 2029, with annual output potentially reaching hundreds of thousands of units.
• Steelfin is designed to integrate with existing fire-control systems, including AEGIS and the Army’s Integrated Battle Command System (IBCS).
• Flight testing of Steelfin variants is scheduled for 2027, following several years of development and ballistic testing.

Background

This development follows Anduril’s expansion into defense manufacturing, including the announcement of a $6.6 billion shipyard in Baltimore in October 2026. It also aligns with broader U.S. military efforts to reduce interceptor costs, such as the Army’s solicitation for a Patriot-compatible interceptor under $1 million and the Navy’s Naval Modular Missile initiative.

How outlets are covering it

While The War Zone emphasizes the ambitious scope of Steelfin’s common architecture, Breaking Defense highlights Anduril’s participation in the Army’s xTech Apex Intercept competition and potential involvement in the Future Interceptor program. Aviation Week’s coverage was limited to technical specifications, whereas Anduril’s official materials focused on the modular nature of the system. There is no direct disagreement on facts, but the emphasis varies from industrial scalability (TWZ) to competitive positioning (Breaking Defense).

Why it matters

The ability to produce affordable, high-volume interceptors is critical for sustaining air defense operations against increasing threats. Steelfin’s modular design could allow the U.S. military to allocate expensive interceptors to high-value targets while using cheaper variants for lower-tier threats, potentially altering the economics of modern warfare.

What to watch

Anduril plans to conduct flight tests of Steelfin variants in 2027. The company aims to reach full-rate production by late 2028 or early 2029, with initial output of several thousand units annually, expanding to hundreds of thousands if demand warrants.