Six Degree-of-Freedom Analysis of the Apollo10 Atmospheric Reentry

The safe return of the Apollo 10 Command Module was well-documented and provides historical data of a real world atmospheric reentry. A 6 degree-of-freedom (6DOF) simulation is developed to recreate the Apollo 10 reentry trajectory for analysis and discussion. The 6DOF simulation environment includes translational and rotational governing equations with accompanying planetary, atmospheric, heat flux, deceleration and aerodynamic torque and force models. A parametric study is conducted by varying the center-of-gravity (CG) location within the capsule along the longitudinal and vertical axis to determine the capsule’s attitude trim characteristics. A quaternion feedback controller is employed to recreate the commanded bank profile designed to mitigate peak heat and deceleration loads and to better target the desired landing location. Simulation results are compared with available NASA historic data and model errors and potential error sources are discussed.