TECHNOLOGY AREA(S): Weapons

ACQUISITION PROGRAM: Mk 41 Vertical Launch System (VLS)

OBJECTIVE: Develop a non-destructive evaluation (NDE) method for measuring the remaining life of ablative material in situ for Navy ducted missile launchers.

DESCRIPTION: The Mk 41 Vertical Launching System (VLS) is a general-purpose missile launcher system capable of supporting air, surface, and underwater engagements.� As part of a ship�s total weapon system, the Mk 41 VLS includes the necessary equipment to stow, identify, select, and schedule a mix of Anti-Air Warfare (AAW), Anti-Submarine Warfare (ASW), and Anti-Surface Warfare (ASuW) missiles. The Ship's Weapons Control System provides the interface to the launcher to route the required electrical signals to and from the missile.� Missiles are launched perpendicular to the ship�s reference plane from canisters positioned below deck to permit rapid engagement of targets in a 360-degree hemispherical volume.� A baseline VLS configuration for the U.S. Navy consists of eight reloadable 8-cell modules that provide a total launch capability of 64 missiles.� Missiles used in VLS utilize solid rocket motors with aluminized propellant.

The Mk 41 VLS utilizes a ducted exhaust system.� In each 8-cell module, missile rocket motor exhaust is routed from the missile canister into a common plenum, then through an uptake (chimney) and vented into the atmosphere.� Ablative panels made from polymeric composites line the internal structure of both the plenum and uptake.� These ablative panels are location dependent and vary in thickness from 0.375-2.000 in. and in sizes up to 2 x 4 feet.� Since the rocket motors utilize aluminized propellant, the expended propellant gas contains particles that erode the composites.� The erosion of the ablative panels determines the life of the module structure.� A new methodology that non-destructively examines the ablative lining in situ to determine the condition and remaining life of the ablative lining will provide a better way to predict the life of the launcher.

Currently, launcher life predictions are based on erosion measurements taken from a few modules used in test programs.� The process requires gathering data before and after launches for a differential analysis.� Measurements are made with a Coordinate measuring machine. These measurements are compared to baseline measurements to obtain the differences in thousandths of an inch.� This methodology cannot be applied to the modules in the fleet because the initial conditions are not recorded on those modules.� Modules also need to have several firings before valid erosion data can be gathered as the ablative materials need to �season� before the wear becomes consistent.� The equipment requires extensive setup and cleaning of the ablative material, which is time consuming.� In addition, only ablative thickness is measured.� Chemical and physical changes are not recorded even though they are occurring.

An innovative technology is needed to collect data on modules in the fleet aboard ship. The technique must utilize non-destructive means that do not interfere with subsequent function of the ablative lining.� The information gathered by this new method will be used to create a NDE that can be correlated to support predictions as to the amount of ablative protection remaining after missile launches.� The goal is to use the data gathered to evaluate the remaining ablative life and efficiently determine if the life of the launcher module can be extended. The technology will be developed on the current polymeric composite ablative materials used in the Mk 41 VLS system (MXB-360 and MKBE-350). The collected data will include ablative material changes such as thickness measured in thousands of an inch and any physical and chemical changes that occur. The data collection will need correlation with a repeatable methodology to provide a high confidence in determining the remaining launcher ablative life.� The Government will provide pertinent launcher technical data and have access to a land-based, full-size launcher to support its concept development.
�
This new technology will be used to make improved prediction on ablative material lining life.

PHASE I: Define and develop a concept to non-destructively measure ablative material linings in situ in Mk 41 VLS.� Feasibility will be established through modeling and analysis. Characterization parameters will meet those in the description of the topic.� The Phase I Option, if awarded, will include the initial design specifications and capabilities description to build a prototype in Phase II. Develop a Phase II plan.

PHASE II: Based on the results of Phase I modeling and analysis, and the Phase II Statement of Work (SOW), design, develop, and deliver a prototype of a new non-destructive measuring method for ablative material linings in situ for the Mk 41 VLS. Either a small-scale (laboratory) demonstration on representative launcher material or a strong analytical simulation showing the potential solution is required. The prototype will clearly demonstrate the ability to accurately provide the needed information for determining the stated parameters in the description. The demonstration can take place at either a Government or company facility. The small business will prepare a Phase III development plan to transition the technology for Navy production and potential commercial use.

PHASE III DUAL USE APPLICATIONS: Assist the Navy in transitioning the full-scale prototype via a full-scale test on a Navy ship (Guided Missile Destroyer (DDG) or Guided Missile Cruiser (CG)).� Assist the Navy in establishing the prototype�s capability via installation and procedural support on the chosen platform.� Also support the Navy in qualification and certification reviews (Navy safety boards) as appropriate.� If the Navy deems the prototype to be a valid capability for measuring the life of the launcher ablative material, a full technical data package will be produced to support future procurement.

This technology is applicable to items or systems implementing NDE of ablative materials, such as the automotive, aircraft, and construction industries.

REFERENCES:

1.� "MK 41 Vertical Launch System (VLS) - Proudly Serving Navies the World Over." Lockheed Martin 2013 http://www.lockheedmartin.com/content/dam/lockheed/data/ms2/documents/launchers/MK41_VLS_factsheet.pdf

2.� Fiore, Eric. "A Promising Future for US Navy: Vertical Launching System." Defense Systems Information Analysis Center Journal, Vol 1 No 2, 2014. https://www.dsiac.org/resources/journals/dsiac/fall-2014-volume-1-number-2/promising-future-us-navy-vertical-launching

3.� Pike, John. "MK 41 Vertical Launch System (VLS)." Military Analysis Network. 1999. https://fas.org/man/dod-101/sys/ship/weaps/mk-41-vls.htm

KEYWORDS: Ablative Panels; Polymeric Composite; Missile Launcher; Propellant Gas; Composites Erosion; Ablative Lining.