RUR-5 ASROC

• Is Missile — yes • Name — RUR-5 ASROC • Origin — United States • Type — Anti-submarine missile • Used By — United States Navy and others • Manufacturer — Honeywell • Unit Cost — Approximately $350,000 (not including warhead) • Designer — Naval Ordnance Test Station Pasadena Honeywell • Service — 1961 • Engine — Solid propellant rocket motor • Weight — 1073 lb • Length — 14.75 ft • Diameter — 16.6 in • Wingspan — 26+7/8 in • Speed — Subsonic • Vehicle Range — 6 mi • Filling — Mark 46 torpedo, 96.8 lb of PBXN-103 high explosive; ktonTNT W44 nuclear warhead (retired) • Detonation — Payload specific • Launch Platform — Surface ships • Illustration — The destroyer Agerholm fires an ASROC with a nuclear depth bomb in shot Dominic Swordfish (1962) • Illustration — ASROC 'Matchbox' reload doors are visible in this photograph of the Japanese, in 2008. • Illustration — ASROC launch from Charles F. Adams, in 1960

ASROC started development as the Rocket Assisted Torpedo (RAT) program by Naval Air Weapons Station China Lake in the early 1950s to develop a surface warship anti-submarine warfare (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 8,000 yd 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 booster 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 Norfolk, its name was changed to ASROC. ASROC was deployed in 1961 and eventually made the majority of USN surface combatants nuclear-capable.

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 banning underwater nuclear tests went into effect. A total of 575 weapons were produced. The W44 weighed 170 lb with a diameter of 13.75 inch and length of 25.3 inch. Following payload separation, the unguided W44 sank quickly to a predetermined depth where the 10-kiloton 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.

One of the first ASROC installations was on Norfolk in 1960. The first large group of ships to receive ASROC were 78 s, modified under the Fleet Rehabilitation and Modernization 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 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. 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 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, these launchers are capable of carrying a mixture of the RUM-139 VL-ASROC, 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.

• Illustration — Map with former RUR-5 operators in red • Japan • Taiwan

• Brazil • Canada • - only on s (after IRE/DELEX modification.) • Germany • - only on s; • Italy • - only on using a Mk 10 GMLS launcher (depot for 40 missiles, between RIM-2 Terrier / RIM-67A SM-1ER and ASROC) • Mexico • South Korea • Pakistan • Spain • Thailand • Turkey • United States