The Standard Missile-6, otherwise known as RIM-174, has revolutionized naval defense since its initial deployment in 2013. The manufacturing company is Raytheon Company, and the SM-6 is a multi-mission ship-launched missile that conducts Anti-Air, Anti-Surface, and Sea-Based Terminal Defense missions. It belongs to the STANDARD missile family of Raytheon, comprising other variants like Standard Missile-1, Standard Missile-2, and Standard Missile-3.
The SM-6 is the first deployed missile of its kind, having multi-mission capabilities that provide Ballistic Missile Defense and Cruise Missile Defense. The herald of a new frontier back in 2015 against ballistic missile threats in their last seconds of flight to ships, it struck its first surface target a year later in 2016. This was important in furthering the U.S. Navy’s concept of ‘dispersed lethality,’ whereby an attack may emanate from any ship or position.
Currently, the SM-6 can be deployed aboard 60 surface ships in the U.S. Navy fleet, with more than 500 missiles already delivered. Software upgrades to the missile have continued to expand its suite of capabilities, including, most recently, its successful intercept of a ballistic missile target in its terminal phase of flight in 2017.
There are three variants of the SM-6: the SM-6 Block I, the SM-6 Block IA, and the SM-6 Dual I. The Block I variant initially deployed on Aegis destroyers had a very advanced rocket booster with advanced motors. The Block IA variant has advanced hardware and software systems to iron out the earlier technical problems that plagued the earlier variants. It successfully engaged a subsonic cruise missile in a test launch in 2014. The Dual I variant, with a designed ability to strike ballistic missiles in the terminal phases of flight, would provide dual capability against both ballistic and cruise missile targets; it is integral to the US Navy’s Sea-Based Terminal program.
Raytheon has received several contracts to produce the SM-6 missile. In 2009, the U.S. Navy awarded a $93-million contract for low-rate initial production of the missile, with the first delivery in 2011. Full-rate production came in 2013 after a contract worth $243 million was agreed upon. Raytheon received a $235 million contract in 2017 to supply the U.S. Navy with advanced SM-6 missiles and spares.
The AMRAAM, or Advanced Medium-Range Air-to-Air Missile, applies advanced signal processing and guidance. It launches from the MK 41 vertical launch system canister with semi-active and active homing guidance for precise engagement of targets. The propulsion system, designed by Aerojet Rocketdyne, is equipped with a dual-thrust rocket motor complete with a moveable nozzle thrust vector control system.
Raytheon’s SM-6 has also gathered interest from other countries. In 2022, South Korea announced plans to spend nearly $600 million acquiring the SM-6 for Aegis-equipped King Sejong the Great-class destroyers (KDX-III) Batch-II. The acquisition will greatly enhance the anti-air and anti-ballistic capabilities of South Korea’s fleet amid criticisms in previous times for citing deficiencies in ballistic missile interceptive capabilities.
This will give the SM-6 a reach of 240 to 460 kilometers, nearly two times that of the current operational range of the SM-2 across the ROKN fleet, and it will contribute to shoring up a country’s defenses against ballistic missile threats from across the North Korean border. The KDX-III Batch-II destroyers, which will start arriving in 2024, have 88 vertical launch system cells for the SM-6, SM-3 Block IB interceptors, and missiles of the type SM-2 Block IB.
The SM-6 has undergone an extended testing and development process. In 2014, the MDA and the Navy initiated a sequence of tests off the coast of the Pacific Ocean. It was particularly designed to test the capability of the missile the intercept short-range ballistic missiles in their terminal phase of flight. Such tests were part of the Multi-Mission Missile Warfare program to validate the capability of the missile and also to certify the first increment of a sea-based terminal defense capability.
It continues to remain the cornerstone of the US Navy’s Naval Integrated Fire Control-Counter Air (NIFC-CA) system with over-the-horizon air defense and capability for nuclear-tipped ballistic missile kill in terminal phases. The dual-mode seeker with semi-active and active radar homing allows the missile to effectively discriminate targets even in the most challenging environments.
It’s still a very important part of today’s naval warfare as the SM-6 continues to evolve, providing flexibility and allowing for multiple mission executions on the water.