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Techniques for Performing Warhead Characterization


OBJECTIVE: Develop an innovative, low cost approach to capture full-hemisphere, open-air, fragment mass, geometry and velocity information during arena and sled warhead characterization tests. DESCRIPTION: MDA is interested in developing techniques to improve the data collection, decrease the time required, and reduce the cost associated with performing ground-based warhead characterization. Warhead characterization tests adhere to the guidelines and procedures described in the Joint Munitions Effectiveness Manual (JMEM). The present method of warhead characterization is costly, labor intensive, and produces only a small amount of the required data. For arena tests, a warhead is placed in the center of an arena consisting of any combination of blast-pressure gages and fragment collection media. Fragment collection media (often celotex bundles) placed behind"switch screens"are placed just above ground level and arc around the warhead at a radius that is a function of the net explosive weight. These screens record the time of impact for the fragments that make contact with the screens and the fragments are captured in the celotex material for subsequent measurement (weight, shape) and analysis. While the bundle radius ensures their survival during blast-pressure impingement, the celotex bundles occupy only a small slice of the total hemisphere. As such, only a fraction of the fragments are captured for inclusion in the subsequent warhead characterization analysis. Weeks of tedious and error-prone labor are necessary to locate, recover, weigh, and describe the geometry of each fragment entering the bundles. Many small fragments are not recovered and few if any individual fragments recovered are mapped to their specific velocities or switch screen entry points/times. In order to develop a more-complete dataset for user consumption, raw warhead test data is subjected to a series of assumptions, averages, rotations, and summarizations to produce an approximation of the true warhead's fragment mass and velocity field. While checks and balances are in place to assure that overall data appear reasonable, individual fragment masses/geometries remain uncoupled from their velocities and many of the smaller fragments are simply not included in the dataset. All warhead characterizations (and data reduction methods) performed to date have been conservatively-skewed based on a lethality-mindset. As such, true munitions lethalities are higher than is indicated by their arena test scores. This is diametrically opposed to the collateral damage mindset of the United States Central Command (CENTCOM) and the requirement to obtain higher fidelity warhead fragmentation/debris data for much of the current inventory of fielded weapons. Current procedures make high-fidelity re-test prohibitively time consuming, expensive, and technically problematic. Delays in missions can result where high casualties or collateral damage are estimated. MDA desires an innovative, cost-effective combined sensor/software technology whereby sensors can assess object movement within large hemispherical volumes (<100 meter radius) at sufficient resolution to detect solid-mass (0.5 gram to 100 kilogram), high-velocity (<1000 meter/second) particles (numbering up to 5000) originating near the center of the test space, and determine individual fragment velocities. The interrogation method must also be capable of estimating/correlating individual fragment masses to their velocities. The proposed interrogation system must be suitable for open-air outdoor arena, sled testing and/or flight test (where debris can be recovered) and sufficiently robust to handle blast overpressures ranging from 1000 psi near the center of the hemispherical test space to 1 psi near the fringes. In addition to fragment velocity and mass information, the technology must be capable of estimating each fragment's geometry. The proposed interrogation system must be capable of setup by no more than two technicians within a single workday and produce an automated post-test report containing fragment velocity data within hours of the test. Contractors are encouraged to take maximum advantage of commercial off the shelf (COTS) sub-technologies and provide confidence in the proposed approach to meet these requirements. PHASE I: Develop an innovative, low cost concept for detecting full-hemisphere warhead fragment data using an automated method to detect and map fragment velocity and provide fragment mass estimates during warhead characterization tests. Demonstrate in the software model the ability to detect, track, and derive position and velocity for each debris object. Develop a plan/design for implementing this system in hardware. PHASE II: Following the development plan outlined in Phase I, design, develop, and implement a warhead characterization system and associated test and data collection software to support a ground-based warhead characterization event. Present the path forward to support a warhead characterization test. PHASE III: Mature the warhead characterization system developed in Phase II to test-ready status and perform data collection during a warhead characterization test. The contractor will document all results. COMMERCIALIZATION: The contractor will pursue commercialization of the various technologies developed in Phase II for potential commercial users in the areas of sensors and software capable of high speed, high fidelity temporal and physical position and size measurements. Once proven, the method could also be utilized in any BMDS flight test engagement or other service intercept (aircraft debris, non-hit to kill debris, etc).
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