000ppt ATK Thiokol Propulsion A Collaborative Effort for Manufacturing and Testing of GEM Rocket Propellant Mike Rose, Connie Murphy and Rich Muscato Presented by:

ATK Thiokol Propulsion 1 Outline Program objectives NSWC-IH Accomplishments Process transition Computer modeling Inert processing Live processing Ballistic differences Motor Firings Conclusions

ATK Thiokol Propulsion 2 Program Objectives NSWC-IH Develop a continuous manufacturing process for TPE based rocket propellant using a twin screw extruder (TSE) Manufacture TPE based rocket propellant in the 40mm TSE and test Establish baseline ballistic data (strands) based on specific ballistic targets for burn rate and slope Provide propellant for high pressure motor firings Transfer process technology to ATK Thiokol for scale-up work ATK Thiokol Scale-up continuous manufacturing process established at NSWC-IH to 58mm TSE Manufacture TPE based rocket propellant in the 58mm and test Compare ballistic data to NSWC-IH baseline targeting burn rate and slope Recover, recycle, re-use (R 3 ) Test high pressure motors using propellant manufactured at NSWC-IH and ATK Thiokol

ATK Thiokol Propulsion 3 NSWC-IH Accomplishments Developed a continuous manufacturing process for TPE based rocket propellant using a twin screw extruder (TSE) Characterized raw material feed streams Flow rates and location Optimized extrusion process parameters for the 40mm TSE Temperature profile, screw configuration and screw speed Successfully and safely manufactured TPE based rocket propellant in the 40mm TSE and established ballistic baseline data Specific targets for burn rate and slope Demonstrated consistent propellant properties from run to run Physical (density) and ballistic (burn rate and slope) properties Provided propellant for high pressure motor firings Transferred process technology to ATK Thiokol for scale-up to 58mm TSE

ATK Thiokol Propulsion 4 58mm TSE Inert Processing Extrusion Protocol for GEM Rocket Propellant Safety Characterization of Energetic Materials Rheological Characterization Performed by NSWC-IH 40mm TSE Parameters Used for Comparison Technology Transfer from NSWC-IH Rheology Characterization Computer Modeling 58mm TSE Energetic Processing

ATK Thiokol Propulsion 5 TSE Computer Modeling Program Developed by the University of Akron Modeling program uses finite element analysis to predict one-dimensional fluid flow behavior in a TSE Program inputs Barrel and screw configuration Temperature profile of the extruder barrel Feed stream flow rates and locations Screw speed (rpm) Material properties (physical and rheological) Program outputs Profiles along the barrel for: Pressure, temperature, torque, fill factor, and melt Specific energy Model benefits Quickly assesses relationships and effects of process parameters

ATK Thiokol Propulsion 6 Modeling Effort Objectives for computer modeling Validate model based on actual extrusion data generated by NSWC-IH for the 40mm TSE Determine comparable process parameters for the 58mm TSE based on 40mm experience Screw configuration, screw speed, temperature profile and feed stream flow rates Modeling results Generated a computer model for the 40mm TSE process that predicted: Pressure, temperature, fill-factor, and melt profiles along the barrel Specific energy Used 40mm data (modeled and actual) to establish a similar model for the 58mm TSE Established initial process parameters for the 58mm TSE The computer model did not predict any major concerns

ATK Thiokol Propulsion 7 Inert Evaluation Inert runs were used to identify critical issues regarding the entire process and to solidify processing parameters for live efforts Initial inert run used a substitute for TPE No unusual temperature excursions were experienced during operation Torque values were higher than expected Modified screw configuration to reduce power consumption Post extrusion examination of the initial inert run identified foiling of the aluminum near the feed inlet of the extruder NSWC-IH experienced foiling in the solid feeder Feed screws were changed solving the problem Cause for the foiling has been attributed to frictional heating TPE substitute did not coat aluminum quickly enough Subsequent runs using actual TPE showed no foiling

ATK Thiokol Propulsion 8 Foiling Phenomenon Foiling on Screw Element Foiling Buildup in the Barrel Foiling Removed from the Barrel Foiling Buildup in the Barrel Aluminum Flakes in the Material

ATK Thiokol Propulsion 9 Initial Live Extrusion Initial live extrusion runs on the 58mm TSE provided valuable information Process parameters modified slightly Screw speed and feed stream flow rates lowered Identified inherent concerns for the system Higher than usual humidity caused AP to hang-up in the feed funnel altering the formulation Provided extrudate for evaluation Established baseline ballistic properties for 58mm TSE material Comparison of ballistic properties from extrudate generated from the 40mm and 58mm TSE showed distinct differences in burn rates

ATK Thiokol Propulsion 10 Ballistic Comparison

ATK Thiokol Propulsion 11 Evaluation of Burn Rate Differences Several factors potentially contributed to ballistic differences of the propellant Raw materials The same raw materials used in the 40mm TSE Porosity Pressed densities generally approached the theoretical maximum density (TMD) of the formulation Re-processed extrudate in batch mixer and measured burn rates Formulation differences Compositional differences could not be determined due to analysis variability Detailed feed stream analysis performed to minimize variability Scale-up idiosyncrasies

ATK Thiokol Propulsion 12 Ballistic Comparison

ATK Thiokol Propulsion 13 Evaluation of Burn Rate Differences Several factors potentially contributed to the ballistic difference Raw materials The same raw materials used in the 40mm TSE Porosity Pressed densities generally approached the theoretical maximum density (TMD) of the formulation Re-processed extrudate in batch mixer and measured burn rates Formulation differences Compositional differences could not be determined due to analysis variability Detailed feed stream analysis performed to minimize variability Scale-up idiosyncrasies

ATK Thiokol Propulsion 14 Feeder Calibration - AP

ATK Thiokol Propulsion 15 Feeder Calibration - Al

ATK Thiokol Propulsion 16 Feeder Calibration – TPE Initial Parameters

ATK Thiokol Propulsion 17 Feeder Data – TPE Adjusted Parameters

ATK Thiokol Propulsion 18 Ballistic Comparison

ATK Thiokol Propulsion 19 Process Scale-up Conclusions Minor material differences (ballistic properties) indicate subtle scale factors exist for the 40mm and 58mm TSE’s Shear environment Heat transfer Process section differences Modular barrel vs. monolithic barrel Exact feed port location Confident that with additional work material properties could be duplicated

ATK Thiokol Propulsion 20 High Pressure Motor Firing Time (sec) Pressure (psia) Predicted Performance Measured Data

ATK Thiokol Propulsion 21 Final Program Conclusions NSWC-IH successfully transferred process technology to ATK Thiokol Two different extruders, size and configuration, can produce similar material Modeling played a key role towards reducing experimental iterations Inert runs provide invaluable process information but should be interpreted carefully Other program objectives are nearing completion Results suggest that successful scale-up can be accomplished