Vapor Containment and Fire Suppression System for Hypergolic Propellants

Hydrazine-based fuels and nitrogen tetroxide-based oxidizers have been the propellants of choice for many propulsion systems over the last several decades due to the propellant combination’s high specific impulse, storability, rapid hypergolic ignition, and moderate densities. Unfortunately, these propellants are highly toxic and pose a significant risk of fire in the event of a spill. These health and safety concerns result in considerable costs associated with their use and severely limit with their use in some applications. IN Space and its partners, ANSUL, Inc. and Purdue University, have formulated a solution that, if successful, will enable the safe storage, transportation, handling and fielding of nitrogen tetroxide-based and hydrazine-based propulsion systems. The proposed Vapor Containment and Fire Suppression system will utilize advanced sensing techniques to detect a propellant leak and then trigger the injection of a persistent, rapidly expanding foam to extinguish fires and contain the propellant vapor to within levels acceptable to the relevant DoD and DoT standards. The envisioned system allows for relatively simple retrofitting of existing and emerging propulsion systems already designed for the hypergolic propellants of interest. Further, the system can be created to offer the reliability, robustness, portability, and safety required to protect personnel and equipment from toxic propellant vapors and fire.