ASROC

ASROC. The Anti-Submarine ROCket is a vertically launched, all-weather standoff anti-submarine weapon system developed for the United States Navy. It was designed to provide surface combatants with a rapid-reaction capability to engage hostile submarines at ranges beyond the reach of conventional ship-launched torpedoes. Entering service in the early 1960s, it became a cornerstone of Cold War anti-submarine warfare for the U.S. Navy and numerous allied fleets, evolving through several variants over decades of service.

Development and history

The program originated in the late 1950s under project designation RAT, driven by the growing threat posed by high-speed, deep-diving Soviet Navy nuclear submarines like the November-class submarine. Developed by Honeywell, the system was intended to bridge the gap between the short range of ASW mortars like Weapon Alpha and the slower deployment of shipboard helicopters. Initial operational capability was achieved aboard the destroyer USS Norfolk (DL-1) in 1960, with formal fleet introduction in 1961. The system saw continuous development, with a major upgrade in the 1980s leading to the Vertical Launch ASROC variant, integrated with the Mk 41 Vertical Launching System. Its development was closely paralleled by similar systems among NATO allies, such as the Ikara and Malafon, and was a direct competitor to the Soviet RPK-2 Viyuga system.

Design and variants

The original RUR-5A ASROC is a rocket-boosted, ballistic delivery system. It consists of a solid-fuel rocket motor attached to a payload of either a Mk 44 or Mk 46 lightweight acoustic homing torpedo, or a Mark 17 nuclear depth bomb. Launched from a dedicated Mk 112 "Matchbox" launcher or later from the Mk 26 Guided Missile Launching System, the rocket follows a ballistic trajectory. At a predetermined point, the payload separates and descends by parachute to water entry. The Vertical Launch ASROC variant is a self-contained canister fired from the ubiquitous Mk 41 VLS, deploying an improved Mk 50 or advanced Mk 54 torpedo. Other notable variants include the short-lived RUR-5A Mod 3 with a Mk 45 ASTOR nuclear torpedo, and the Japanese-developed RUM-139 VL-ASROC.

Operational use

ASROC was deployed extensively aboard numerous U.S. Navy vessel classes throughout the Cold War, including *Charles F. Adams*-class and *Spruance*-class destroyers, *Belknap*-class cruisers, and *Knox*-class frigates. It provided these ships with a critical quick-strike ASW capability, often working in concert with embarked SH-2 Seasprite or SH-60 Seahawk helicopters from Helicopter Anti-Submarine Squadrons. While never used in combat by the U.S., live-fire exercises were routine. The system saw export and licensed production to key allies; for instance, the Japan Maritime Self-Defense Force employed it on their *Murasame*-class ships, and the Republic of China Navy equipped their *Kee Lung*-class with the system. The VLA variant remains in the active inventory, deployed on *Arleigh Burke*-class destroyers.

Capabilities and specifications

The operational range of the original ASROC was approximately 6 to 10 nautical miles, allowing a launching ship to engage submarines well outside the effective range of the submarine's own torpedoes like the Mk 37 or UGST. The VLA variant extended this to over 12 nautical miles. The primary warhead for conventional variants is a lightweight torpedo, which after parachute deployment conducts an autonomous search pattern using active/passive sonar. The nuclear-capable version carried the W44 warhead in the Mk 17 depth bomb, with a yield estimated in the low kiloton range. Launch platforms required integrated AN/SQS-53 or AN/SQS-56 sonar systems for target data, with fire control managed by the AN/SWG-1 Vector Analyzer Group or later the AN/SQQ-89 combat system.

Operators

The primary operator has always been the United States Navy. Significant international operators have included the Japan Maritime Self-Defense Force, which also conducted licensed production. The system was also exported to several allied nations during the Cold War, such as Brazil for its *Niterói*-class frigates, Germany for the *Bremen*-class, Greece for the *Elli*-class, Italy for the *Durand de la Penne*-class, Taiwan, Turkey for the *Barbaros*-class, and South Korea for the *Gwanggaeto the Great*-class. Many of these operators have since retired the original system in favor of newer technologies like the RUM-139 VL-ASROC or helicopter-delivered torpedoes.

Category:Anti-submarine rockets Category:Naval weapons of the United States Category:Cold War anti-submarine weapons