SM-3

RIM-161 SM-3
A RIM-161 Standard Missile (SM-3) is launched from the Aegis cruiser USS Lake Erie
Type	Aegis Ballistic Missile Defense System
Place of origin	United States, Japan (Block IIA)
Service history
Used by	United States Navy Japan Maritime Self-Defense Force
Production history
Manufacturer	Raytheon, Aerojet, (Mitsubishi Heavy Industries Block IIA)
Unit cost	US$9–24 million (2011) US$11.2m(FY2014) (Block 1B)
Specifications
Weight	1.5 t
Length	6.55 m (21 ft 6 in)
Diameter	34.3 cm (13.5 in) for Block I missiles 53.3 cm (21 in) for Block II
Warhead	Lightweight Exo-Atmospheric Projectile (LEAP) kinetic warhead
Wingspan	1.57 m (62 in)
Propellant	Stage 1: MK 72 Booster, solid-fuel, Aerojet Stage 2: MK 104 Dual Thrust Rocket Motor (DTRM), solid-fuel, Aerojet Stage 3: MK 136 Third Stage Rocket Motor (TSRM), solid-fuel, ATK Stage 4: Throttleable Divert and Attitude Control System (TDACS), [Aerojet]
Operational range	700 km (378 miles) Block IA/B 2,500 km (1,350 miles) Block IIA
Speed	3 km/s (Mach 10.2) Block IA/B 4.5 km/s (Mach 15.25) Block IIA
Guidance system	GPS/INS/semi-active radar homing/passive LWIR infrared homing seeker (KW)

The RIM-161 Standard Missile 3 (SM-3) is a ship-based missile system used by the United States Navy to intercept short-to intermediate-range ballistic missiles as a part of Aegis Ballistic Missile Defense System. Although primarily designed as an anti-ballistic missile, the SM-3 has also been employed in an anti-satellite capacity against a satellite at the lower end of low Earth orbit. The SM-3 is primarily used and tested by the United States Navy and also operated by the Japan Maritime Self-Defense Force.

The SM-3 evolved from the proven SM-2 Block IV design. The SM-3 uses the same solid rocket booster and dual thrust rocket motor as the Block IV missile for the first and second stages and the same steering control section and midcourse missile guidance for maneuvering in the atmosphere. To support the extended range of an exo-atmospheric intercept, additional missile thrust is provided in a new third stage for the SM-3 missile, containing a dual pulse rocket motor for the early exo-atmospheric phase of flight.

Initial work was done to adapt SM-3 for land deployment ("Aegis ashore") to especially accommodate the Israelis, but they then chose to pursue their own system, the NATO code-name Arrow 3. A group in the Obama administration envisioned a European Phased Adaptive Approach (EPAA) and SM-3 was chosen as the main vector of this effort because the competing U.S. THAAD does not have enough range and would have required too many sites in Europe to provide adequate coverage. Compared to the GMD's Ground-Based Interceptor however, the SM-3 Block I has about  ¹⁄₅ to  ¹⁄₆ of the range. A significant improvement in this respect, the SM-3 Block II variant widens the missile's diameter from 0.34 m (13.5 in) to .53 m (21 in), making it more suitable against intermediate-range ballistic missiles.