A Miniaturized SERS Based Sensor Technology for Liquid Hypergolic Propulsion Systems

Hypergolic fuels such as monomethylhydrazine, and oxidizers such as nitrogen tetroxide are attractive for use in divert and attitude control systems (DACS) for variety of reasons. However, due to their toxicity, corrosivity, carcinogenicity, and flammability, hypergolic fuels and oxidizers are corrosive represent a significant safety hazard in the event of leaks. Given the potential need to transport and deploy systems containing hypergolic propellants there is a need for safety technologies to be incorporated to detect potential hypergolic fuel related hazards. An ideal such sensor should: detect MMH/NTO leaks inside canisters to the levels of less than 50 ppm, have a standalone lifetime>4 years, be small, light weight, and low power, operate without providing false positive readings, provide"smart"sensor functionality, and facilitate logistically advantageous data transfer. The objective of the proposed work is to develop such a sensing module, based on the combination of a miniaturized surface enhanced Raman scattering (SERS) spectroscopy concept, and existing low-power wireless sensor network hardware. This Phase I effort will include: working with OEMs to define requirements, conducting chemical kinetics/degradation analyses, the evaluation of the sensing module hardware/packaging design concepts, and the construction and proof of principle demonstration of first generation hardware.