Air Defense

Standard Missile-3 (SM-3)

Also known as
  • RIM-161 Standard Missile 3
  • RIM-161 SM-3 Block I
  • SM-3 Block I
  • SM-3 Block IA
  • SM-3 Block IB
  • SM-3 Block IB Threat Upgrade
  • SM-3 Block IIA

The Standard Missile-3 is the Aegis ballistic-missile-defense interceptor behind the RIM-161 SM-3 Block I, Block IA, and Block IB lineage. Fired from shipboard and Aegis Ashore Mk 41 launchers, it carries a kinetic kill vehicle above the atmosphere to defeat ballistic missiles in midcourse flight and has documented U.S. combat use against Iranian missile attacks.

Standard Missile-3 (SM-3), Ship- and ground-launched exo-atmospheric ballistic missile interceptor, Air Defense
Image source: SM-3 Block IIA Hawaii launch photo

Role in Conflicts

Block Snapshot

SM-3 evolved through distinct blocks, each pushing the family farther, faster, or with better discrimination.

VariantService milestonePublic unit costWhat changed
Block IAOperational from 2005Not publicly standardizedOriginal sea-based Aegis BMD interceptor.
Block IBFirst combat use in April 2024About $12.5 millionImproved discrimination software and the variant credited with the first combat intercepts.
Block IIAProcurement line active in FY2025About $31.4 millionU.S.-Japan co-development with greater speed, reach, and a larger kill vehicle.

Source labels used here: Standard Missile-3 (SM-3), FY2025 MDA Procurement Justification Book, and USS Ross Successfully Intercepts Ballistic Missile Target During Coalition Test.

Profile / Specs

Profile

Origin
United States
Built by
Raytheon
Type
Ship- and ground-launched exo-atmospheric ballistic missile interceptor
Service note
2005-present
Unit cost
About $12.5 million for Block IB and about $31.4 million for Block IIA in FY2025 Missile Defense Agency procurement estimates.
Produced
2005-present
Number built
At least 336 acquired by 2018; Raytheon says more than 400 interceptors have been delivered to U.S. and Japanese navies.

Specifications

Length
6.55 m
Range
About 700 km for Block IA/IB; about 2,500 km for Block IIA
Speed
About 3.0 km/s for Block IA/IB; about 4.5 km/s for Block IIA
Diameter
Block IA/IB use a 21-inch booster with a 13.5-inch upper body; Block IIA uses a 21-inch body.
Launch platforms
Mk 41 Vertical Launch System on Aegis ships and Aegis Ashore sites
Guidance
Inertial, command, and midcourse GPS
Propulsion
Solid-fuel, three-stage interceptor
Kill mechanism
Exo-atmospheric hit-to-kill vehicle derived from Lightweight Exo-Atmospheric Projectile technology
Variants

The Block I family covers the early 13.5-inch-body SM-3 interceptors; Block IIA is a wider U.S.-Japan co-development with greater reach.

VariantConfigurationDesignation notes
Block IAFirst-generation Block I interceptor

CSIS identifies Block IA as the first deployed SM-3 Block I variant and lists a 2005 service entry for the initial Block I fielding.

Sources: Standard Missile-3 (SM-3)

Block IBSecond-generation Block I interceptor

The Block IB adds the two-color infrared seeker and improved divert/attitude-control capability; USNI identified Block IB missiles in the April 2024 combat debut.

Sources: Standard Missile-3 (SM-3), SM-3 Ballistic Missile Interceptor Used for First Time in Combat, SM-3 Interceptor

Block IB Threat UpgradeSoftware and discrimination update

CSIS describes the Threat Upgrade as a Block IB update for more complex ballistic-missile targets, with development testing in FY2016 and a production-representative intercept in 2017.

Sources: Standard Missile-3 (SM-3)

Block IIAWider U.S.-Japan co-developed interceptor

Block IIA uses a 21-inch body with larger rocket motors and a larger kill vehicle for greater speed, reach, and discrimination capability.

Sources: Standard Missile-3 (SM-3), SM-3 Interceptor

Aegis BMD Context

SM-3 sits inside the Aegis ballistic missile defense architecture rather than operating as a standalone missile.

Compatible itemItem typeCompatibility evidence
Aegis Combat System, Shipboard integrated combat system, Naval SystemsAegis Combat SystemCombat system

Raytheon describes SM-3 as part of the Aegis ballistic missile defense family, and Navy reporting ties SM-3 firings to Aegis-equipped destroyers and their fire-control architecture.

Sources: SM-3 Interceptor, USS Lassen Departs Yokosuka After 10 Years Forward Deployed

Why the relationship matters

The missile's real capability comes from the shipboard or ashore sensing, fire-control, and launch architecture that makes exo-atmospheric intercepts possible.

Sources: SM-3 Interceptor, Standard Missile-3 (SM-3)

Launch Systems

SM-3 is launched from Aegis-equipped ships through the Mk 41 VLS.

LauncherLauncher typeLaunch evidence
Aegis Combat System, Shipboard integrated combat system, Naval SystemsAegis Combat SystemShipboard integrated combat system

Raytheon describes SM-3 as part of the Aegis ballistic missile defense family, and Navy reporting ties SM-3 firings to Aegis-equipped destroyers.

Sources: SM-3 Interceptor, SM-3 Ballistic Missile Interceptor Used for First Time in Combat

Timeline

Standard Missile-3 (SM-3) Key Events

  1. Initial SM-3 Block IA operational fielding

    CSIS describes the SM-3 family as operational from 2005, marking the original sea-based Aegis BMD interceptor entering service.

    Sources: Standard Missile-3 (SM-3)

  2. First non-U.S. range intercept

    USS Ross fired an SM-3 Block IA during the MTMD Forum's At Sea Demonstration, which the Navy said was the first SM-3 launch on a non-U.S. range and the first ballistic-missile intercept in the European theater.

    Sources: USS Ross Successfully Intercepts Ballistic Missile Target During Coalition Test

  3. First combat use

    U.S. destroyers in the Eastern Mediterranean fired SM-3 Block IB interceptors against Iranian ballistic missiles during the defense of Israel, the interceptor family's first documented combat use.

    Sources: SM-3 Ballistic Missile Interceptor Used for First Time in Combat

  4. SM-3 intercept near Turkish airspace

    Business Insider reported that USS Oscar Austin fired an SM-3 against an Iranian ballistic missile in Turkish airspace, the third such SM-3 engagement by a Navy destroyer in two weeks.

    Sources: U.S. Navy Destroyers Firing SM-3s at Iranian Missiles

Media

Standard Missile-3 (SM-3) Videos

Standard Missile-3 (SM-3) Images

Standard Missile-3 (SM-3), Ship- and ground-launched exo-atmospheric ballistic missile interceptor, Air Defense - view 1
Source: SM-3 satellite-intercept photo
Related Weapon Systems
Standard Missile-2 (SM-2), Shipboard surface-to-air missile family, MunitionsMunitionsStandard Missile-2 (SM-2)Shipboard surface-to-air missile familyThe Standard Missile-2 (SM-2) is a Raytheon-built shipboard surface-to-air missile family used by U.S. and allied navies for fleet area air defense and ship self-defense. Aegis ships launch SM-2 from vertical launch systems, guide it by inertial navigation and mid-course commands, and use semi-active radar or infrared terminal homing in later medium-range blocks. U.S. Navy reporting documents USS Carney firing an SM-2 in October 2023 during Red Sea defense operations against Houthi missiles and drones.
Evolved Sea Sparrow Missile, Ship self-defense missile, MunitionsMunitionsEvolved Sea Sparrow MissileShip self-defense missileThe Evolved Sea Sparrow Missile is a NATO-cooperative ship self-defense missile family built by Raytheon for surface combatants and carrier self-defense. U.S. Navy, RTX, and NATO Seasparrow sources describe it as a medium-range guided weapon for anti-ship cruise missiles, aircraft, drones, and maneuvering surface threats; documented combat use includes USS Mason's 2016 Yemen self-defense engagement and Red Sea crisis firings against Houthi threats.
PAC-3, Hit-to-kill Patriot interceptor missile, Air DefenseAir DefensePAC-3Hit-to-kill Patriot interceptor missilePAC-3 is the hit-to-kill interceptor family for Patriot air-defense batteries, using active radar homing and direct-impact defeat against tactical ballistic missiles, cruise missiles, aircraft, and other high-value air threats. PAC-3 CRI gives Patriot launchers a dense 16-round loadout, while PAC-3 MSE uses a larger dual-pulse motor and control changes for greater defended battlespace; documented combat and transfer contexts include Iraq in 2003, Yemen, Ukraine, and U.S.-Qatari Patriot defense during the June 2025 Iran missile attack on Al Udeid.

Sources

Standard Missile-3 (SM-3)Publisher: Center for Strategic and International Studies | Note: Supports SM-3 family background, launch method, variants, service history, the 2018 inventory count, and technical specifications. | Accessed: 2026-07-02SM-3 InterceptorPublisher: Raytheon | Note: Supports Raytheon manufacturer background, the SM-3 interceptor's hit-to-kill role, and its place in the Aegis ballistic missile defense family. | Accessed: 2026-07-02RTX SM-3 Production AgreementsPublisher: RTX | Note: Supports Raytheon production-agreement context for the SM-3 family and confirms the line remains in production. | Accessed: 2026-07-02SM-3 Ballistic Missile Interceptor Used for First Time in CombatPublisher: USNI News | Note: In the 2020 United States-Iran Conflict, USS Arleigh Burke and USS Carney fired SM-3 interceptors at Iranian ballistic missiles in the Eastern Mediterranean. | Accessed: 2026-07-02U.S. Navy Destroyers Firing SM-3s at Iranian MissilesPublisher: Business Insider | Note: Supports 2026 Iran War direct conflict-use: U.S. Navy destroyers used SM-3 interceptors against Iranian ballistic missiles entering or heading toward Turkish airspace. | Accessed: 2026-07-02USS Ross Successfully Intercepts Ballistic Missile Target During Coalition TestPublisher: U.S. Navy | Note: Supports the 2015 SM-3 Block IA coalition demonstration and the first non-U.S. range launch of the interceptor. | Accessed: 2026-07-02USS Lassen Departs Yokosuka After 10 Years Forward DeployedPublisher: U.S. Navy | Note: Supports the RIM-161 Standard Missile-3 designation used in Navy reporting and the VLS context on Aegis destroyers. | Accessed: 2026-07-02FY2025 MDA Procurement Justification BookPublisher: U.S. Missile Defense Agency | Note: Supports FY2025 procurement-line unit costs for SM-3 Block IB and SM-3 Block IIA production. | Accessed: 2026-07-02SM-3 Block IIA Hawaii launch photoPublisher: Wikimedia Commons | Note: Image provenance and public-domain licensing for the SM-3 Block IIA launch image. | Accessed: 2026-07-02SM-3 satellite-intercept photoPublisher: Wikimedia Commons | Note: Image provenance and public-domain licensing for the SM-3 anti-satellite launch image. | Accessed: 2026-07-02