Reduced-Order Modeling of an Entry Capsule from Simulated Ballistic Range Trajectories

Entry, descent, and landing (EDL) relies on blunt-body entry vehicles, or entry capsules, to survive atmospheric entry and successfully complete planetary missions. In the supersonic through the transonic flight regime, these entry capsules can display dynamic instabilities. While research is ongoing to leverage nonlinear functional fits to determine dynamic stability coefficients, advancements in computational fluid dynamics–rigid body dynamics (CFD-RBD) simulations produce rich aerodynamic data, which might aid researchers in understanding and quantifying the dynamic stability characteristics of these capsules. The objective of this research is to build upon previous work that developed an aerodynamic Reduced-Order Model (ROM) to predict forced rotational oscillation trajectories, addressing key limitations. A ROM is a form of field-based surrogate model capable of efficiently leveraging high-fidelity aerodynamic data to mimic the results of CFD simulations. Results showed success at predicting the mean aerodynamic trends of a free-flight validation trajectory for 𝐶𝑃
and 𝐶𝐹 data for both the heatshield and backshell regions using a ROM methodology.