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Rolling Airframe Missile



A RIM-116 Rolling Airframe Missile being launched from a Mk 31 GMWS system on a San Antonio class landing platform dock in 2009
Source: US Navy - © Public domain

United States
Surface to air missile
Entered service
1992 for Block 0
2000 for Block 1
2015 for Block 2
In service
1976 - 1985
United States - General Dynamics
Germany - Diehl BGT Defence
1987 - Present
United States - Raytheon (previously General Dynamics)
Germany - MBDA / Diehl BGT Defence
Unit cost
US$ 273.000 for Block 0 in mid 1990's
US$ 444.000 for Block 1 in 1999
US$ 998.000 in 2014
US$ 905.000 in 2021
Number produced
About 1.400 Block 0 by 1999
RAM / Rolling Airframe Missile
Notable users
United States



The Rolling Airframe Missile is a modern era surface to air missile of US-German origin. Development started in the late Cold War era and was a joint USA and West German effort. The goal was to develop a point defense system against inbound anti-ship missiles which had greater performance and standoff range than gun-based systems. RAM was the first dedicated missile design for naval missile defense.


The Rolling Airframe Missile itself is a unique combination of proven off-the-shelf components. The main body of the missile, including rocket motor and warhead, are from the AIM-9 Sidewinder short range air to air missiles. The infrared seeker comes from the Stinger man portable surface to air missile. Two radio antenna are fitted to the seeker head. These provide the ability for passive radar homing. Since these operate in a single plane, the missile needs to spin in order to determine the direction of the inbound anti-ship missile. This rolling of the airframe is what gives the RAM missile its name. Over time the missile saw minor and major improvements in several blocks.


The RAM has a speed between Mach 2 and 3. Maximum effective range is about 9 km for early models and 15 km for Block 2 missiles. Although the RAM can reach several kilometers in altitude it is most likely to be employed against sea skimming missiles. An effectiveness of 95% has been derived from live fire tests. In practice the success rate will most likely depend on the target parameters, including target characteristics, saturation, weather conditions and countermeasures.


The RAM uses a dual mode seeker. The passive radar homing guidance is used to steer the missile towards an inbound anti-ship missile. The infrared homing seeker has increased performance the closer it is to the target. This is used in the terminal stage. A laser proximity fuse detonates the blast-fragmentation warhead near the target missile. Guidance has been continuously improved over time. The infrared seeker has been updated to include the ultraviolet spectrum and later became an imaging infrared seeker. An infrared all the way guidance was also added to target inbound missiles that do not use active radar homing. The passive radar homing has been updated to function in ECCM conditions. A software update added the ability to target helicopters, aircraft and surface vessels. The latest update includes a datalink for communication between missiles in flight.


The RAM is predominantly used in the Mk 31 Guided Missile Weapon System. This includes one or more 21-cell launchers and a central command post that is integrated with the ship's radar systems. In 2009 the SeaRAM became operational. This is a much simpler and more compact system that is based on Phalanx close-in weapon system. Classes of ships that have been fitted with RAM range from fast patrol boats to aircraft carriers. Frigates and destroyers are the most common types of ship to be fitted with RAM systems.


The RAM was jointly developed by the United States and West Germany. These two nations are the early adopters and placed the most sizeable orders. About a dozen nations have adopted the RAM. These include NATO nations and various other nations around the world with close ties to the United States. RAM remains in production and is actively marketed and installed on new classes of ships.



A RIM-116 Rolling Airframe Missile being launched from a Mk 31 GMWS system on a Nimitz class aircraft carrier in 2016.
Source: US Navy - © Public domain

List of RAM variants

RIM-116A Block 0
Original production version that entered operational service in 1992. Uses radar frequency seeker for initial stage of flight and infrared seeker in terminal stage.
RIM-116B Block 1
Similar to Block 0, but adds an infrared-only guidance mode for use against missiles without active radar homing. Performance against sea skimming missiles was also improved. Entered series production in the year 2000.
RIM-116B Block 1A
Software update for Block 1 that adds the HAS mode. This allows it to be used against helicopters, aircraft and surface targets.
RIM-116C Block 2
Deep modernization of the RAM. New larger diameter rocket motor for a range increase of 50%. Four control fins instead of two improve the agility of the missile. The seeker was improved to be able to home in on low probability of intercept radar homing missiles.
RIM-116E Block 2B
RAM Block 2B is an improvement over Block 2 that adds a missile-to-missile interface. This allows two missiles in flight to communicate with each other.


Facts RIM-116A Block 0 RIM-116B Block 1 RIM-116C Block 2
United States / Germany
Surface to air missile
2.79 m
127 mm
434 mm
73.5 kg
Guidance mode
Passive radar homing initial phase
Infrared guidance terminal phase
All aspect, head-on due to inbound missile scenario
Blast fragmentation
9.1 kg
Laser proximity fuse
Solid propellant rocket motor
MK 112
Engagement envelope
Mach 2+
0.8 km minimum
9 km maximum
1.5 m minimum
6.1 km maximum

Launch platforms

Mk 31 GMWS

The Mk 31 GMWS is first and most common system used to launch the RIM-116 RAM missile. This system uses one or more 21-cell Mk 49 GMLS launchers and is connected to the ship's sensors and combat data management system.


The RAM Alternate Launching System (RALS) was developed for smaller vessels for which the entire Mk 31 GMWS was too large or expensive. This German/Danish development had a 10 missile capacity. It never reached operational state.


The SeaRAM is a standalone launcher derived from the Mk 15 Phalanx close-in weapon system. SeaRAM holds a total of 11 RAM missiles ready to fire.


Related articles

FIM-92 Stinger

The RIM-116 RAM uses the infrared seeker design from the FIM-92 Stinger man portable SAM system.