UNITED24 - Make a charitable donation in support of Ukraine!


RIM-116 RAM Rolling Airframe Missile

The RAM program is designed to provide surface ships with an effective, low-cost, lightweight, self-defense system which will provide an improved capability to engage and defeat incoming antiship cruise missiles (ASCMs). RAM is a joint United States and German venture to design an effective, low cost, lightweight quick-reaction, self-defense system which will increase the survivability of otherwise undefended ships. It is a 5 inch missile that utilizes SIDEWINDER technology for the warhead and rocket motor, and the STINGER missile's seeker. Cueing is provided by the ship's ESM suite or radar. The MK-31 RAM Guided Missile Weapon System (GMWS) is defined as the MK-49 Guided Missile Launching System (GMLS) and the MK-44 Guided Missile Round Pack (GMRP). The launching system and missiles comprise the weapon system.

RAM is a NATO cooperative program with Germany. Memorandums of Understanding between the United States and Germany have been signed for the development and production of the RAM Block 0 as well as for the development of RAM Block I. Operational since 1992, over 50 US and German ships are now armed with the missile, designed as an autonomous, quick-reaction, all-weather, fire-and-forget system using passive radio frequency/infrared (RF/IR) dual-mode guidance. The complete RAM Mk 31 Guided Missile Weapon System combines the Mk 44 Guided Missile Round Pack and the 21-cell Mk 49 Guided Missile Launching System (GMLS). The missile itself is designated RIM-116A (Block 0) and RIM-116B, (Block 1).

The RAM Block 0 weapon system consists of a 21-round missile launcher, below-deck electronics, and a guided missile round pack. The round pack consists of a 5-inch, supersonic missile and launching canister, which interfaces the missile and the launcher. The RAM Block 0 autonomous homing missile has a five-inch diameter airframe that rolls in flight and dual mode, passive radio frequency/infrared (RF/IR) guidance. In its initial configuration (Block 0), RAM was designed to engage RF-radiating ASCMs, which represented the majority of the threat. The RF emission provided by the target's radar seeker is used by the dual-mode seeker of RAM for lock-on after launch and provides midcourse guidance; the IR radiation of the target is used for terminal guidance. Immediately after launch, the RF seeker guides the missile towards the target and points the IR seeker to the target direction, initiating RF midcourse guidance. Initial homing for RAM Block 0 is on the threat missile's radar signature, using an ASCM's RF seeker emissions. If the ASCM's IR radiation is acquired, RAM transitions to IR guidance.

In May 1993, the Assistant Secretary of the Navy for Research, Development, and Acquisition approved RAM Block 0 for production. Subsequently, the missile has had successful intercepts in 127 of 132 production proofing and ship qualification test flights in both the US and German navies.

Since 1993, the RAM Block 0 has been installed on all five LHA ships, eight DD 963 ships, six LHD ships, and eight LSD class ships. Navy installation plans call for RAM Block 0 installations in one DD 963 class ship and on LHD 7 (currently under construction). All other planned RAM installations call for the RAM Block I configuration.

Operational Evaluation (OPEVAL) of RAM Block 0 was conducted from January to April 1990. It was assessed to be potentially operationally effective and potentially operationally suitable, but there were shortfalls in its ability to handle, under all environmental and tactical conditions, the full spectrum of threats. In April 1993, a decision was made to pursue rectification of OPEVAL deficiencies by implementing a block upgrade. RAM Block 1 is the upgraded missile.

The Block I upgrade provides the RAM missile with an increased capability to intercept cruise missiles by means of an infrared only acquisition technique. Effective against a wide spectrum of existing threats, the RAM Block 1 IR upgrade incorporates a new IR "all-the-way-homing" guidance mode to improve AW performance against evolving passive and active ASCMs. The Block 1 missile retains all capabilities of the Block 0 missile while adding two guidance modes, IR only and IR Dual Mode Enable (IRDM). The IR only mode guides on the IR signature of the ASCM. The IRDM will guide on the IR signature of the ASCM while retaining the capability of utilizing RF guidance if the ASCM RF signature becomes adequate to guide on. RAM Block I can be launched in an IR all-the-way mode, as well as the dual mode (passive RF, followed by passive IR) used by Block 0.

RAM weapon systems are integrated with the AN/SWY-2 combat system on certain ships and as part of the Ship Self Defense System (SSDS) on other ships (LSD-41 class ships). The AN/SWY-2 is comprised of the weapon system and the combat direction system. The combat direction system employs the existing Mk 23 target acquisition system (TAS) radar and the AN/SLQ-32(V) electronic warfare support sensor together with threat evaluation and weapons assignment software resident in the Mk 23 TAS to accomplish threat detection, correlation, evaluation, and engagement. With SSDS, RAM is part of the engagement suite. For example, on LSD 41-class ships, a typical SSDS engagement suite includes RAM, the PHALANX Close-In Weapon System Block 1A, and the decoy launch system. SSDS further integrates the AN/SPS-49(V)1 radar with the medium PRF upgrade, the AN/SPS-67 surface search radar, the AN/SLQ-32(V) sensor, and the CIWS search radar. RAM is installed in all five Tarawa (LHA-1)-class amphibious assault ships; LHD 1, 3, 5, and 6; DD-987, and LSD-48. Block 0 missiles and launchers are in production and on schedule, and the missile had successful intercepts in 62 of 64 production-proofing and ship qualification tests. The first fleet firing of the RAM occurred in October 1995 from the USS Peleliu (LHA-5). A successful preliminary design review of the Block 1 IR upgrade was conducted in September 1995. Flight tests of the missile are being conducted during Engineering and Manufacturing Development, prior to authorizing Low-Rate Initial Production (LRIP). Milestone III was achieved in FY 1998, to be followed by IOC in FY 1999.

Based on the results of operational testing conducted aboard the U.S.S. Gunston Hall (LSD 44) in January 1999 and the Self-Defense Test Ship between March and August 1999, the Commander, Operational Test and Evaluation Force, declared the RAM Block I to be operationally effective against a variety of cruise missile threats and recommended fleet introduction. The Block I missile had successful intercepts in 23 of 24 development test firings. A full-rate production decision occurred in January 2000.

As of March 2000, RAM Block I had been installed on two LSD class ships and is pending installation on two LSD 41 class ships, LHD 7, and CVN 76. Navy installation plans call for Block I installations or upgrades on 8 LSD 41/49, 3 DD 963, 12 CV/CVN, 7 LHD, and 12 LPD 17 (new construction) ships between 2001 and 2006. Though not yet funded, the Navy also plans to install RAM Block I upgrades on all five LHA class ships during fiscal year 2007.

In November 1998, the United States and Germany amended the Block I development Memorandum of Understanding to include scope and funding for the development of a helicopter/aircraft/surface craft (HAS) upgrade of the RAM missile. Requiring only software changes to the RAM Block I missile, the HAS upgrade will extend RAM targets to include helicopters, aircraft, and surface ships. Navy plans indicate that all RAM installations on LSDs, LHDs, LPDs, and CV/CVNs will be the HAS configuration by 2009. Also, the Navy is developing an 11-round guided missile launcher in the HAS mode configuration for installation on CG 52 through 73 between 2004 and 2009.

The IR seeker is a narrow-field device, capable of terminal target acquisition only. This requires the target to radiate in order to achieve passive RF acquisition for initial guidance. In the latest Block 1 missile, the IR homing element of the missile has been upgraded with a completely new image-scanning seeker with intelligent digital signal processing. This confers IR-all-the-way guidance capability to the dual-mode system, enabling the engagement of non-RF-radiating targets in full range of the missile. Target search and IR lock-on is autonomously performed by the seeker during flight. The digital signal processing, in combination with the instantaneous detector resolution, provides an excellent IR counter measures capability.

The Block 1 development program was successfully completed in August 1999, with an Operational Evaluation (OPEVAL) conducted aboard the Self-Defense Test Ship to demonstrate the system's introduction maturity. In 10 scenarios, Harpoon, Exocet and supersonic (Mach 2.5) Vandal target missiles were intercepted and destroyed under realistic conditions. RAM Block 1 achieved first-shot kills on every target in its presented scenarios, including sea-skimming, diving and highly maneuvering profiles in both single and stream attacks. Milestone III approval for Block 1 full-rate missile production followed in January 2000.

A software upgrade to be introduced this year will enable Block 1 missiles to also engage fixed- and rotary-wing aircraft and surface targets. The Helicopter, Aircraft and Surface (HAS) capability will exploit the Block 1 missile's IR seeker design and performance characteristics, adding new software functionality to enable slow-flying air targets and surface vessels, such as fast attack craft (FACs), to be engaged. No hardware changes are required to accommodate the HAS modification.

The first export order for RAM was received in December 1999 when the Republic of Korea placed a US$24.9 million contract for three Mk 49 GMLSs (followed in October 2000 by a contract for 64 RAM Block 1 missiles) for its new KDX-2 air-defense destroyers. This was followed in April 2000 when Greece's Elefsis Shipyards signed a direct commercial sale with RAM-System for the supply of three Mk 49 GMLSs for three new 62 m FACs being built for the Hellenic Navy.

The U.S. Navy successfully achieved Initial Operational Capability (IOC) for the Block 2 Rolling Airframe Missile (RAM) aboard the amphibious transport dock ship USS Arlington (LPD 24) 15 May 2015. The new RAM Block 2 missile is designed to counter advanced anti-ship cruise missile threats that U.S. and Allied Navies face. Prior to the IOC declaration, the U.S. Navy and German government successfully demonstrated the enhanced ship self-defense effectiveness of the Block 2 RAM during testing at the Pacific Missile Range Center at Point Mugu, California, between May 2013 and March 2015.

The IOC declaration is the culmination of cooperative developmental and operational testing events between the U.S. Navy and the German government spanning the last two years. Compared to previous configurations, Block 2 provides significantly improved kinematic performance in maneuverability and range as well as a more sophisticated radio frequency receiver. These improvements allow RAM to increase the battlespace and engage low probability of intercept threats at longer ranges.

RAM is a highly successful, 39-year U.S. cooperative program with the German government that has yielded the U.S. taxpayer more than $800 million in cost avoidance and has delivered arguably one of the most capable anti-ship cruise missile defense systems in the world. RAM protects the U.S Navy's CVN, LCS, LHA, LHD, LSD and LPD 17 class warships and twenty-two of Germany's warships.

Join the GlobalSecurity.org mailing list

Page last modified: 01-07-2021 17:59:59 ZULU