View source for RUR-5 ASROC

{{short description|Anti-submarine missile system}}
{{redirect|ASROC|the vertical-launch variant|RUM-139 VL-ASROC|the Taiwanese manufacturer|ASRock}}
{{Infobox weapon
 | is_missile        = yes
 | name              = RUR-5 ASROC
 | image             = ASROC launcher.JPG
 | image_size        = 300
 | caption           = ASROC Launcher on board the {{ship|German destroyer|Mölders}}
 | origin            = United States
 | type              = [[Anti-submarine missile]]<ref name= "joliehist">{{cite web | last= Jolie | first = E.W. | title = A Brief History of US Navy Torpedo Development: ASROC Missile | date = 15 September 1978 | publisher = Maritime | url= https://www.maritime.org/doc/jolie/part2.htm | access-date = 21 June 2013}}</ref>
 | used_by           = [[United States Navy]] and others
 | manufacturer      = [[Honeywell]]<ref name= "1987 almanac">Thomas, Vincent C. ''The Almanac of Seapower 1987'', Navy League of the United States (1987) {{ISBN|0-9610724-8-2}} pp.190–91</ref>
 | unit_cost         = Approximately $350,000 (not including warhead)
 | designer          = Naval Ordnance Test Station Pasadena<ref name= "joliehist" /><br />[[Honeywell]]
 | production_date   = 
 | service           = 1961<ref name="1987 almanac"/>
 | engine            = Solid propellant rocket motor<ref name="1987 almanac"/>
 | weight            = {{convert|1073|lb|kg}}<ref name="1987 almanac"/>
 | length            = {{convert|14.75|ft|m|abbr= on}}<ref name="1987 almanac"/>
 | height            = 
 | diameter          = {{convert|16.6|in|mm}}
 | wingspan          = {{convert|26+7/8|in|mm}}
 | speed             = Subsonic
 | vehicle_range     = {{convert|6|mi|km|abbr=on}}<ref name= "NavInstGuid89">{{cite book | last = Friedman | first = Norman | title = The Naval Institute Guide to World Naval Weapons Systems, 1988–1989 | publisher = [[United States Naval Institute Press]] | date = 1989 | location = [[Annapolis]], [[Maryland|MD]], USA | page = 414 | url = https://books.google.com/books?id=3XKuAAAAIAAJ | isbn = 0-87021-793-3}}</ref>
 | ceiling           = 
 | altitude          = 
 | filling           = [[Mark 46 torpedo]], {{convert|96.8|lb|kg}}<ref name= "1987 almanac"/> of PBXN-103 high explosive; {{cvt|10|ktonTNT|TJ}} [[W44 (nuclear warhead)|W44 nuclear warhead]] (retired)
 | detonation        = Payload specific
 | launch_platform   = [[Surface combatant|Surface ships]]<ref name= "joliehist" />
}}
[[File:Nuclear depth charge explodes near USS Agerholm (DD-826) on 11 May 1962.jpg|thumb|The destroyer {{USS|Agerholm|DD-826|6}} fires an ASROC with a nuclear depth bomb in shot [[Operation Dominic|Dominic Swordfish]] (1962)]]
[[File:TV 3516 Asagiri.JPG|thumb|ASROC 'Matchbox' reload doors are visible in this photograph of the Japanese {{sclass|Asagiri|destroyer|2}}, in 2008.]]
[[File:USS Charles F. Adams (DDG-2) launches a RUR-5 ASROC on 18 November 1960 (KN-1916).jpg|thumb|ASROC launch from {{USS|Charles F. Adams|DDG-2|6}}, in 1960]]

The '''RUR-5 ASROC''' (for "Anti-Submarine Rocket") is an all-weather, all sea-conditions [[Anti-submarine missile|anti-submarine missile]].{{Disputed inline|Is the ASROC a missile or a rocket?|date=December 2025}} Developed by the [[United States Navy]] in the 1950s, it was deployed in the 1960s, updated in the 1990s, and eventually installed on over 200 USN surface ships, specifically [[cruiser]]s, [[destroyer]]s, and [[frigate]]s. The ASROC has been deployed on scores of warships of many other navies, including Canada, Germany, Italy, Japan, Taiwan, Greece, Pakistan and others.<ref name= "NavInstGuid98">{{cite book | last = Friedman | first = Norman | title = The Naval Institute Guide to World Naval Weapons Systems, 1997–1998 | publisher = [[United States Naval Institute Press]] | date = May 1997 | location = [[Annapolis]], MD, USA | page = 668 | url = https://books.google.com/books?id=l-DzknmTgDUC&pg=PA668 | isbn = 1-55750-268-4}}</ref>

==History==
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:<ref>[https://books.google.com/books?id=5d0DAAAAMBAJ&dq=rocket+assisted+torpedo&pg=PA108 "Navy Homing Torpedoes Fights Subs."] ''Popular Mechanics'', April 1958, p. 108.</ref>  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 {{convert|8,000|yd|m}} 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]] {{USS|Norfolk|DL-1|6}}, its name was changed to ASROC.<ref>Bill Gunston ''Rocket & Missiles'', Salamander Books Ltd 1979, ISSB 0-517-26870-1</ref><ref name=Fried280-287>{{cite book | last = Friedman | first = Norman | author-link = Norman Friedman | title = US Destroyers: An Illustrated Design History | publisher = Naval Institute Press | year = 2004 | pages = 280–287 | location = Annapolis | isbn = 1-55750-442-3 | edition = Revised }}</ref> ASROC was deployed in 1961 and eventually made the majority of USN surface combatants nuclear-capable.

==Description==
[[File:Inert ASROC missile on JS Shimakaze(DDG-172) left front view at JMSDF Hanshin base December 10, 2017 01.jpg|thumb|left|alt=dummy ASROC round in IJN service|Dummy ASROC round]]
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 VL-ASROC|RUM-139 Vertical Launch ASROC]], or "VLA".<ref name="NavInstGuid98" />

After a surface ship, patrol plane or anti-submarine helicopter detects an enemy [[submarine]] by using [[sonar]] 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]]<ref name=Brit>"Asroc" in ''[[Encyclopædia Britannica|The New Encyclopædia Britannica]]''. Chicago: [[Encyclopædia Britannica Inc.]], 15th edn., 1992, Vol. 1, p. 639.</ref> or a W44 [[nuclear depth bomb]] 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]] or [[passive sonar]].

===W44 nuclear depth charge===
The W44 nuclear depth charge entered service in 1961,<ref>{{cite journal |last=Polmar |first=Norman |year=1983 |title=Tactical Nuclear Weapons |journal= [[Proceedings (magazine)|Proceedings]] |volume=109 |issue=7 |page=125 |publisher=[[United States Naval Institute]] }}</ref> 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 {{convert|170|lb|kg|abbr=on|order=flip}} with a diameter of {{convert|13.75|inch|cm|sigfig=2|abbr=on|order=flip}} and length of {{convert|25.3|inch|cm|abbr=on|order=flip}}. 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.<ref name="NavInstGuid98" />

==Specific installations==

One of the first ASROC installations was on {{USS|Norfolk|DL-1}} in 1960. The first large group of ships to receive ASROC were 78 {{sclass|Gearing|destroyer|2}}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.<ref name=Fried280-287/><ref>[https://www.navsource.net/archives/05/helpers/fram.htm Special Feature – FRAM at NavSource]</ref>

The 31 [[U.S. Navy]] {{sclass|Spruance|destroyer|2}}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.<ref>Friedman 2004, p. 482</ref>

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 (missile)|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 {{sclass|Knox|frigate|0}} destroyer escorts (frigates)) or a variation of the Tartar missile in limited distribution.

Ships with the [[Mark 26 missile launcher|Mk 26 GMLS]], and late marks of the [[List of United States Navy Guided Missile Launching Systems|Mk 10 GMLS]] aboard the {{sclass|Belknap|cruiser|2}}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 [[Mark 41 Vertical Launch System|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.

==Operators==
[[File:RUR-5 operators.png|thumb|400px|Map with former RUR-5 operators in red]]

;{{Navy|Japan}}
;{{Navy|Taiwan}}

===Former operators===
;{{Navy|Brazil}}
;{{Navy|Canada}}
: - only on {{sclass|Restigouche|destroyer|2}}s (after IRE/DELEX modification.)
;{{Navy|Germany}}
: - only on {{sclass|Lütjens|destroyer|2}}s
;{{Navy|GRE}}
;{{Navy|Italy}}
: - only on {{ship|Italian cruiser|Vittorio Veneto|550|2}} using a Mk 10 GMLS launcher (depot for 40 missiles, between [[RIM-2 Terrier]] / [[RIM-67 Standard#RIM-67A SM-1 Extended Range|RIM-67A SM-1ER]] and ASROC)
;{{Navy|Mexico}}
;{{Navy|South Korea}}
;{{Navy|Pakistan}}
;{{Navy|Spain}}
;{{Navy|Thailand}}
;{{Navy|Turkey}}
;{{Navy|United States}}

==See also==
* {{lwc|Ikara (missile)|Ikara}}
* {{lwc|Hong Sang Eo}}
* {{lwc|Malafon}}
* {{lwc|Otomat#Developments|MILAS}}
* {{lwc|RUM-139 VL-ASROC}}
* {{lwc|Sea Lance}}
* {{lwc|SUBROC}}
* {{lwc|Terasca}}
* [[List of nuclear weapons]]
* [[Nuclear weapon design]]
* {{lwc|SUW-N-1}}

==References==
{{reflist}}

==External links==
{{Commons category|ASROC}}
* https://fas.org/man/dod-101/sys/missile/vla.htm {{Webarchive|url=https://web.archive.org/web/20150428060652/http://fas.org/man/dod-101/sys/missile/vla.htm |date=28 April 2015 }}
* http://www.gyrodynehelicopters.com/asroc.htm
* https://designation-systems.net/dusrm/r-5.html
* [http://www.navweaps.com/Weapons/WMUS_ASROC.htm DiGiulian, Tony Navweaps.com ASROC page]
* [https://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html Allbombs.html] list of all US nuclear warheads at [http://nuclearweaponarchive.org nuclearweaponarchive.org]

{{Honeywell}}
{{US military rockets}}
{{US Navy torpedoes}}

{{Use dmy dates|date=June 2017}}

{{DEFAULTSORT:Rur-5 Asroc}}
[[Category:Anti-submarine missiles of the United States]]
[[Category:Anti-submarine weapons]]
[[Category:Cold War nuclear missiles of the United States]]
[[Category:Ballistic missiles of the United States]]
[[Category:Cold War anti-submarine weapons of the United States]]
[[Category:Naval guided missile launch systems of the United States|Mk016]]
[[Category:Naval weapons of the United States|RUR005]]
[[Category:Honeywell]]
[[Category:Military equipment introduced in the 1960s]]