SBIR-STTR Award

This study will identify and verify a higher performance and density electrically controlled solid propellant. The propellant under investigation utilizes the energetic oxidizer Hydroxylamine nitrate with other nitrate co-oxidizers that prevent oxidizer crystallization down to 20 degrees centigrade and lower. The oxidizers are combined with the energetic polymer polyvinyl amine nitrate (PVAN) and are processed as a solution solid propellant. While this system is highly conductive, it liquefies at temperatures above 100 degrees centigrade and does not readily extinguish once ignited. This makes it infeasible for use as an electrically controlled extinguishable solid propellant as is. To overcome these drawbacks requires chemically crosslinking the polymer after the propellant has been mixed, cast and solidified through the plastisol cure. This will ensure propellant dimensional stability during combustion. Liquid, electrically conductive additives will also be incorporated into the propellant that will aid in extinguishment when voltage is turned off. This will be verified in small test sample burns using both ac and dc electric current. The voltage, current and thrust will be measured and utilized to identify power requirements associated with propellant ignition, burn rate and extinguishment.The proposed propellant system would provide a more energetic and reliable propulsion system for the precise placement of low power microsatellites. In addition, this is a low-hazard, low-toxicity system that could replace current toxic and problematic liquid and solid propellants utilized in ship based munition systems

This research is directed towards the development of a high energy electrically controlled solid propellant for maneuvering thrusters in micro satellites. Combustion of this propellant will depend on the continuous but low level input of electrical energy. Extinguishment will take place rapidly upon removal of this electrical energy. The propellant will have a principal oxidizer and a base binder. The oxidizer will be formulated to retain its liquid state down to - 20 degrees centigrade. The resultant propellant will be aged at 35 and 50 degrees centigrade for a period of 6 months. The aged propellant will be tested for DSC, TGA, density, ignition, combustion, extinquishment and electrical resistivity. These results will be compared to the results from the same tests for these propellants prior to aging. A final formulation will be selected. Repeated batches will be made of this formulation to establish reproducibility and samples will be furnished to the Electric Propulsion Lab at AFRL for combustion testing in small motor configurations. Industry requirements and specifications will be researched to enable proper tailoring of propellant properties and performance