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Ablative Material for Missile Launchers

Description:

TECHNOLOGY AREA(S): Weapons 

OBJECTIVE: Develop new ablative materials that extend the life of the Mark 41 Vertical Launch System (VLS). 

DESCRIPTION: The Mark 41 VLS is a general-purpose missile launching system capable of supporting air, surface, and underwater engagements. As part of a ship’s total weapon system, the Mark 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 8-cell modules, which provide a total launch capability of 64 missiles. Missiles used in VLS utilize solid rocket motors with aluminized propellant. Exhaust temperatures are 5,000°F or higher with an exposure time of less than one second (10 seconds in a restrained fire event). The Mark 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, through an uptake (chimney) and vented into the atmosphere. Polymeric composite ablative panels line the internal structure of both the plenum and uptake to provide heat protection. Since the rocket motors utilize aluminized propellant, the expended propellant gas contains particles that increase composite erosion. The wear of these panels determines the life of the module structure. Once the surface is worn to a certain thickness, the VLS has to be discarded. New ablative materials that outperform MXB-360 and MKBE-350 in terms of wear during launches are desired without increasing weight greater than 10% above the current 112 pounds per cubic foot (1.8 g/cc), or increasing heat transfer to the module structure. The current ablative thermal conductivity is approximately .50W/m-K. The new materials must cost less than $10 per pound. Many ablatives in use today are single use items, like re-entry vehicles. Investigation has indicated most research has focused on that type of use. The use of ablatives in Mark 41 VLS is unique in that once the ablative is installed in the launcher module; it is exposed to multiple erosion events from various rocket motors over the course of the launcher life. The ablative is not replaced or repaired in this time. There can be long periods between launches and the lifetime may exceed 20 years. Replacement ablative systems are desired to increase the launch count to 20 or more. This will include the physical design of the system suitable for use in the Mark 41 VLS launcher. If the ablative solution is in a similar form, with similar machining and bonding characteristics of the current ablative, it is unlikely that direct involvement with the VLS manufacturer will be required. However, the VLS Program Office representative will facilitate coordination between the vendor and VLS manufacturer if the vendor chooses to pursue a teaming arrangement. The company will be expected to provide an analysis of the material behavior in response to representative environmental conditions (temperature, humidity, shock, vibration). The company will also provide insight as to best practices for manufacturing methodology for its chosen material(s), pre-assembly (if applicable), and launcher installation. Providing an improved ablative material for Navy missile launchers will increase the longevity of the launcher while withstanding missile rocket motor launches and restrained fires. 

PHASE I: Develop a concept for new ablative materials to extend the life of Mark 41 VLS. The concept will show technical feasibility of new ablative materials for the Mark 41 VLS. Feasibility will be established through modeling and analysis of materials that meet the description parameters. A small-scale (laboratory) material demonstration, at representative temperatures and exposure times, or a strong analytical model showing ablative material improvement will be required. 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 ablative material for the Mark 41 VLS. The prototype will clearly demonstrate the capability to increase the longevity of the launching system as described in the description. The company will be provided pertinent launcher technical data and have access to a land-based, full-size launcher to support its prototype development. The demonstration will take place at a Government- or company-provided facility. The company will prepare a Phase III development plan to transition the technology for Navy production and potential commercial use. 

PHASE III: Assist the Navy in evaluating and transitioning full-scale prototype ablative materials to allow for further experimentation and refinement. This will include a full installation initially on a land-based system, followed by installation on a representative platform (e.g., DDG, CG) or the Navy Self Defense Test Ship. The prototype implementation should be a fully functional ablative material to support future procurement for the Mark 41 VLS. New ablative materials could be applicable to items or systems implementing ablative materials in the automotive, aircraft, and construction industries. 

REFERENCES: 

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

2:  Fiore, Eric. "MK 41 Vertical Launching System." DSIAC Journal, Fall 2014, p. 32-34. 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)." FAS Military Analysis Network, 1999. https://fas.org/man/dod-101/sys/ship/weaps/mk-41-vls.htm

KEYWORDS: Ablatives; Polymeric Composite; MK41 Vertical Missile Launcher; Aluminized Propellant Gas; Heat Protection From Missile Launch; Composites Erosion 

CONTACT(S): 

Stephen Grossen 

(540) 653-3639 

stephen.grossen@navy.mil 

Julio Jimenez 

(703) 872-1049 

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