Advanced Chemistry and Radiation Modules for Wake and Reentry Flows

The flowfields surrounding reentry and other hypersonic vehicles are complex and challenging to model. At hypersonic velocities, the flow may ionize and form a plasma sheath around the vehicle, ablating heat shield material can be entrained in the flow, and non-local thermodynamic equilibrium (NLTE) effects can become important. All these effects can change the vehicle electro-optic (EO) and radar cross section signatures, interfering with tracking, targeting, and aim-point selection. Spectral Sciences, Inc. (SSI) proposes to develop innovative chemistry and radiation software modules to upgrade existing MDA engineering and next generation hypersonic wake/reentry flowfield signature tools. The modules will be interfaced to existing MDA engineering and next generation application codes, and then validated against field data, to create a practical and accurate end-to-end simulation capability for hypersonic wake/reentry EO signatures and radar cross sections. The proposed approach is based on several innovations including: a novel way to include critical NLTE chemistry and radiation physics with accuracy and computational efficiency, the ability to generate chemical rates and spectroscopic data for neutrals and ions for various relevant materials, and a modular design that can be readily integrated to upgrade existing and next generation MDA signature tools.