The RUR-5 ASROC (for "Anti-Submarine Rocket") is an all-weather, all sea-conditions anti-submarine missile system. Developed by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

in the 1950s, it was deployed in the 1960s, updated in the 1990s, and eventually installed on over 200 USN surface ships, specifically

cruiser A cruiser is a type of warship. Modern cruisers are generally the largest ships in a fleet after aircraft carriers and amphibious assault ships, and can usually perform several roles. The term "cruiser", which has been in use for several hu ...

destroyer In naval terminology, a destroyer is a fast, manoeuvrable, long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against powerful short range attackers. They were originally developed in ...

s, and

frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed and ...

s. The ASROC has been deployed on scores of warships of many other navies, including Canada, Germany, Italy, Japan, the Republic of China, Greece, Pakistan and others.

History

ASROC started development as the Rocket Assisted Torpedo (RAT) program by the Naval Ordnance Test Station at China Lake in the early 1950s to develop a surface warship ASW weapon to counter the new post-World War II submarines which ran quieter, at much higher speed and could attack from much longer range with high speed homing torpedoes. In addition, the goal was to take advantage of modern sonars with a much larger detection range. An extended range torpedo delivered by parachute from the air would allow warships the stand-off capability to attack hostile submarines with very little advance notice to the hostile submarine. The RAT program came in three phases: RAT-A, RAT-B and RAT-C. RAT-A and its follow-on, RAT-B, were compact and economical stand-off weapons for smaller warships, but were determined to be either unreliable or had too short a range. RAT-C was developed as a stand-off ASW weapon that used a nuclear depth charge. This required a range of at least to escape potential damage from the underwater blast. The RAT-C was considerably larger than the previous RAT program rockets to accommodate the extended range needed and was for larger warships. After the failure of both the RAT-A and RAT-B programs, RAT-C was redesigned to use not only a nuclear depth charge but also a homing ASW torpedo. To obtain the accuracy needed, the RAT-C rocket launcher had to be redesigned with larger side fins. This program finally combined reliability and accuracy, along with the required stand-off range. Before RAT-C reached operational status in 1960, aboard the large US Navy

destroyer leader Destroyer leader (DL) was the United States Navy designation for large destroyers from 9 February 1951 through the early years of the Cold War. United States ships with hull classification symbol DL were officially frigates from 1 January 1955Blac ...

, its name was changed to ASROC. ASROC was deployed in 1961 and eventually made the majority of USN surface combatants nuclear-capable.

Description

The first ASROC system using the MK-112 "Matchbox" launcher was developed in the 1950s and installed in the 1960s. This system was phased out in the 1990s and replaced with the RUM-139 Vertical Launch ASROC, or "VLA". After a surface ship, patrol plane or anti-submarine helicopter detects an enemy

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

by using

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...

or other sensors, it could relay the sub's position to an ASROC-equipped ship for attack. The attacking ship would then fire an ASROC missile carrying an acoustic homing

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, su ...

"Asroc" in ''

The New Encyclopædia Britannica ''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the m ...

''. Chicago: Encyclopædia Britannica Inc., 15th edn., 1992, Vol. 1, p. 639. or a W44

Nuclear Depth Bomb A nuclear depth bomb is the nuclear equivalent of the conventional depth charge, and can be used in anti-submarine warfare for attacking submerged submarines. The Royal Navy, Soviet Navy, and United States Navy had nuclear depth bombs in their ...

onto an unguided ballistic trajectory toward the target. At a pre-determined point on the missile's trajectory, the payload separates from the missile and deploys a parachute to permit splashdown and water entry at a low speed and with minimum detectable noise. Water entry activates the torpedo, which is guided by its own sonar system, and homes in on the target using either

active sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on or ...

passive sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...

W44 nuclear depth charge

The W44 nuclear depth charge entered service in 1961, but was never used beyond one or two tests before the Limited

Nuclear Test Ban Treaty The Partial Test Ban Treaty (PTBT) is the abbreviated name of the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, which prohibited all test detonations of nuclear weapons except for those conducted u ...

banning underwater nuclear tests went into effect. A total of 575 weapons were produced. The W44 weighed with a diameter of and length of . Following payload separation, the unguided W44 sank quickly to a predetermined depth where the 10-

kiloton TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by that convention to be , which is the approximate energy released in the detonation of a t ...

warhead detonated. The nuclear-armed ASROC was never used in combat. W44-armed ASROC missiles were retired by 1989, when all types of nuclear depth bombs were removed from deployment.

Specific installations

One of the first ASROC installations was on in 1960. The first large group of ships to receive ASROC were 78 s, modified under the

Fleet Rehabilitation and Modernization The Fleet Rehabilitation and Modernization (FRAM) program of the United States Navy extended the lives of World War II-era destroyers by shifting their mission from a surface attack role to that of a submarine hunter. The FRAM program also covere ...

Mark I program (FRAM I) in the early 1960s. A Mark 112 8-tube ASROC launcher was added along with other major modifications. ASROC reloads were stowed alongside the helicopter hangar and handled by a small crane. The 31

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...

s were all built with the Mark 16 Mod 7 ASROC Launching Group and MK 4 ASROC Weapons Handling System (AWHS) reload system. These had one standard Mark 112 octuple ASROC launcher, located immediately above a reload system holding an additional 16 assembled rounds (two complete reloads of eight missiles apiece). Thus, each ''Spruance''-class destroyer originally carried a maximum total of 24 ASROC.Friedman 2004, p. 482 Most other US Navy and allied navy destroyers, destroyer escorts, frigates, and several different classes of cruisers only carried the one ASROC "matchbox" MK 112 launcher with eight ASROC missiles (although later in service, some of those missiles could be replaced by the

Harpoon A harpoon is a long spear-like instrument and tool used in fishing, whaling, seal hunting, sealing, and other marine hunting to catch and injure large fish or marine mammals such as seals and whales. It accomplishes this task by impaling the t ...

anti-ship missile). The "matchbox" Mk 112 launchers were capable of carrying a mixture of the two types. Reloads were carried in many classes, either on first level of the superstructure immediately abaft the launcher, or in a separate deckhouse just forward or abaft the Mk 112. The MK 16 Launching Group also had configurations that supported RGM-84 Harpoon (onboard destroyer escorts (frigates)) or a variation of the Tartar missile in limited distribution. Ships with the Mk 26 GMLS, and late marks of the Mk 10 GMLS aboard the s, could accommodate ASROC in these power-loaded launchers (the Mk 13 GMLS was not able to fire the weapon, as the launcher rail was too short). Most ''Spruance''-class destroyers were later modified to include the

Mk 41 VLS The Mark 41 Vertical Launching System (Mk 41 VLS) is a shipborne missile canister launching system which provides a rapid-fire launch capability against hostile threats. The Vertical Launch System (VLS) concept was derived from work on the Aegis C ...

, these launchers are capable of carrying a mixture of the

RUM-139 VL-ASROC The RUM-139 VL-ASROC is an anti-submarine missile in the ASROC family, currently built by Lockheed Martin for the U.S. Navy. History Design and development of the missile began in 1983 when Goodyear Aerospace was contracted by the U.S. Navy to de ...

, the Tomahawk TLAM, and other missiles. All of the ''Spruance'' destroyers carried two separate quad Harpoon launchers. Other US ships with the Mk 41 can also accommodate VL-ASROC.

Operators

; ;

Former operators

; ; : - only on s (after IRE/DELEX modification.) ; : - only on s ; ; : - only on using a Mk 10 GMLS launcher (depot for 40 missiles, between

RIM-2 Terrier The Convair RIM-2 Terrier was a two-stage medium-range naval surface-to-air missile (SAM), and was among the earliest surface-to-air missiles to equip United States Navy ships. It underwent significant upgrades while in service, starting with be ...

/ RIM-67A SM-1ER and ASROC) ; ; ; ; ; ; ; and : - same configurations as US Navy were also deployed on some

United States Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mult ...