The U.S. Navy’s Program Executive Office, Integrated Warfare Systems, unveiled a new design for the hypersonic SM-6 Block IB at the Surface Navy Association’s 2025 Symposium earlier this month, breaking from the previous rifle round design that featured a traditional 13.5-inch diameter guidance and warhead section and 21-inch motor section.
The new design, unveiled during a panel at SNA 2025, shows a new SM-6 Block IB concept with a uniform 21-inch diameter body closely matching the SM-3 Block IIA. The first stage booster is also significantly longer.
Previous SM-6 Block IB concepts have shown a rifle casing design for the rocket motor, with the missile keeping a 13.5-inch diameter for the warhead and electronics segment. The redesigned body will result in less aerodynamic stresses given speeds the new SM-6 is expected to achieve.
Northrop Grumman tested a 21-inch booster in December of 2024 in “support of the U.S. Navy’s future extended-range capability needs.” It is likely that this motor is intended for the hypersonic SM-6 Block IB.
“The Standard Missile-6 (SM-6) Block IB is an upgrade of the SM-6 BLK IAU, which provides long-range fires capability by implementing improved software and replacing the existing Mk 104 Dual-Thrust Rocket Motor (DTRM) with a new 21-inch rocket motor to extend the range. The SM-6 BLK IB delivers to the Navy and Joint Force a transformative multi-domain, multi-mission offensive hypersonic kinetic capability.”
U.S. Navy FY2025 Budget Documents
Low rate production of the SM-6 Block IB began in FY2024. A milestone B decision expected at the end of 2025. The hypersonic missile is expected to reach initial operational capability in FY2026. Raytheon (RTX) is the prime contractor for the program.
