This project focuses on the development and research applications of a new state-of-the-art global numerical model of the atmosphere extending from the ground to 500 km altitude, which can provide a foundation for future high-altitude operational numerical weather prediction (NWP). This research will be based around an emerging next-generation Navy dynamical core known as NEPTUNE (Navy Environmental Prediction System Utilizing a Nonhydrostatic Engine), which solves the deep-atmosphere nonhydrostatic fluid equations on the sphere using spectral element (SE)/Galerkin methods, allowing efficient parallelization out to millions of cores in preparation for next generations of massively parallel supercomputer systems. Work to improve key dynamical and physical aspects of the model are the central themes of this project, and can include (but are not restricted to) the following: SE/Galerkin algorithms, implicit/explicit time integrators, structured/unstructured/adaptive grids, static mesh refinement, limited-area configurations, species transport algorithms, fast physics parameterizations for the stratosphere, mesosphere and thermosphere including new “scale-aware”, “gray-zone” and stochastic parameterizations, radiative/chemical heating and cooling rates, diffusive separation of thermospheric species by molecular viscosity, and drag effects of gravity waves, viscosity and ion-neutral coupling. Programming skills in some subset of Fortran, C/C++, python, and MPI/OpenMP are highly advantageous for this research work.