Utilizing Ground-Based Simulation to Validate High Altitude Plume Signature Codes in Support of Theater Missile Threat Detection and Tracking

The proposed SBIR program will employ Physical Sciences Inc.’s (PSI) unique ground-based high altitude plume signature simulation facility to examine the interactions of hyperthermal oxygen atoms with specific plume constituents believed to contribute to plume emission in the ultraviolet and visible spectral regions. These reactions will include the multi-step O + CH4 reaction predicted to produce CO(a?X) emission, the brightest molecular emission band observed in far-field plume signatures resulting from firing monomethylhydrazine/N2O4 bipropellant engines on the space shuttle. To perform measurements of such multi-collision reactions, PSI will design and fabricate an upgraded expansion chamber for the testing facility to allow signature observation at several fluxes of atomic oxygen. The results of these measurements will be compared against computational chemistry models of the same reaction system, performed by Spectral Sciences, Inc. (SSI) as a subcontractor on the proposed effort. Reaction phenomenology and cross sections determined as part of this effort will be integrated into the chemical databases of SOCRATES-P, the DoD’s primary high-altitude plume signature modeling code, developed by SSI. This integration will extend the capability of the code to accurately predict plume signatures, particularly in the critical UV and visible spectral ranges.