RUM-139 VL-ASROC

RUM-139 VL-ASROC is a vertical-launch anti-submarine rocket developed for the United States Navy. It is designed to deliver an acoustic homing torpedo to a distant target area, providing warships with a standoff capability against hostile submarines. The system entered service in the 1990s and represents a key evolution from earlier rocket-assisted torpedo systems like the RUR-5 ASROC.

Development and Design

The development of the RUM-139 was initiated to leverage the new Mk 41 Vertical Launching System (VLS) being widely installed on major United States Navy surface combatants, including the Ticonderoga-class cruiser and Arleigh Burke-class destroyer. The program was managed by the Loral Corporation, with later work transitioning to Lockheed Martin following corporate acquisitions. The design centered on a solid-fuel rocket booster that would carry a payload—initially the Mark 46 torpedo and later the Mark 54 torpedo—to a pre-programmed point, where the torpedo would be parachuted into the water to begin its autonomous search. This approach combined the long-range delivery of the RUR-5 ASROC with the flexibility and rapid-fire capability of the VLS, a significant advancement over older, trainable launchers like the Mark 112 ASROC Launcher. The integration of the weapon required sophisticated fire control from the ship's Aegis Combat System or other combat direction systems to calculate the optimal launch and torpedo entry points.

Operational History

The RUM-139A achieved initial operational capability with the United States Navy in 1993. It was deployed primarily aboard Ticonderoga-class cruisers and early Arleigh Burke-class destroyers, forming a critical layer of the fleet's Anti-submarine warfare (ASW) defense during the post-Cold War era. While specific combat use is not publicly documented, the weapon system has been a standard component of battle group operations and exercises, such as those conducted by the United States Pacific Fleet. The improved RUM-139B variant, which integrated the newer Mark 54 torpedo, entered service in the late 1990s. The production line for the U.S. Navy closed in 2003, though existing stocks remain in the inventory. The system's operational concept has influenced subsequent developments, including the ASROC-type capabilities seen in other navies and the ongoing evolution of the U.S. Navy's Undersea Warfare capabilities.

Technical Specifications

The RUM-139 is a canister-launched, solid-propellant rocket. Its payload is a lightweight anti-submarine torpedo, initially the Mark 46 torpedo and later the Mark 54 torpedo. Guidance for the rocket phase is provided by an inertial navigation system, with flight commands sent from the launching ship's combat system. Upon reaching the designated point, the rocket motor separates, and the torpedo payload descends by parachute, entering the water to activate its own sonar and propulsion. The torpedo then employs active or passive acoustic homing to engage the target submarine. The entire system is integrated with the Mk 41 Vertical Launching System, allowing for salvo launches and 360-degree coverage without the need to train a launcher.

Variants

* RUM-139A: The initial production variant, fielded in 1993, which carried the Mark 46 Mod 5 torpedo as its payload. * RUM-139B: An upgraded variant that entered service around 1998. Its primary improvement was the integration of the newer Mark 54 torpedo, which offered enhanced performance in shallow-water environments against quieter, modern submarines.

Operators

* United States: The primary operator, used by the United States Navy. * Japan: The Japan Maritime Self-Defense Force (JMSDF) inducted the system, designated as the RUM-139A, for use on its Kongō-class destroyers and other major surface combatants equipped with the Mk 41 Vertical Launching System.

Category:Anti-submarine missiles of the United States Category:Vertical launch systems