The National Geospatial-Intelligence Agency (NGA) requires specialized research and software development services to enhance advanced gravimetric and planetary modeling capabilities. The prospective vendor will be required to provide supplies and services in the following core areas: Planetary Modeling: Develop high-fidelity, variable-resolution planetary models (for Earth and other planetary bodies) with complex density variations to validate derived gravimetric quantities. Software Development & Optimization: Integrate, improve, and optimize NGA-provided analytic continuation code, evaluating it for parallel computation and operational use. Algorithm Development: Research and implement memory-efficient computational techniques (e.g., out-of-core inverse methods) for estimating spherical harmonic expansion (SHE) model coefficients. Exploratory Research: Collaborate with NGA Subject Matter Experts (SMEs) to evaluate and investigate new mathematical, modeling, and algorithmic techniques that align with the overall project goals. For full technical specifications, baseline code parameters, and validation methodology requirements, please refer to the attached solicitation documents.