The Department of Defense (DoD) has made digital engineering (DE) a mandatory strategic imperative for how its components design, develop, deliver, operate and sustain defense systems. This research opportunity covers a wide range of issues related to digital engineering transformation. This includes utilizing dedicated model-based systems engineering (MBSE) and DE development environments like Cameo/MagicDraw, System Composer, ModelCenter, Innoslate to build a system or mission architecture; connecting this architecture with simulation environment like NSS, MAST, AFSIM to provide an operational context, as well as integrating it with models developed in the domain-specific development environments like MATLAB/Simulink or finite element analysis software or data-based AI/ML models to ensure high fidelity. Another venue could be using generative AI to automate / accelerate systems/missions design. The ultimate goal is to develop executable high-fidelity architectures and experimentable digital twins of systems and their missions to meet the DoD objectives.