Aerodynamic Oscillation and Attitude Control Analysis for Reentry Capsule using OREX Flight Data and Wind Tunnel Data

Stable attitude control is essential for accurate reentry capsule guidance, and aerodynamic instability of a transonic region has been recognized as a key issue. To address this issue, we have been studying stable attitude control for lifting reentry capsule during reentry flights. As the first step of the study, we evaluated the aerodynamic stability and controllability of the Japanese ballistic reentry capsule named OREX (Orbital Re-entry EXperiment). The study compares reentry flight results with simulation results base on aerodynamic coefficients obtained from wind tunnel tests and aerodynamic damping coefficients modeled from wind tunnel tests and existing aerodynamic data-bases. We have also been analyzing the aerodynamic stability and controllability of a lifting reentry capsule by conducting attitude control simulations using aerodynamic damping coefficients estimated from the wind tunnel tests for dynamic stability characteristics. This paper describes the OREX system configuration, aerodynamic damping coefficients, reentry flight results, and a comparison of results obtained from flight data and simulations. Moreover we present the lifting reentry capsule model, aerodynamic damping coefficients estimated from wind tunnel tests, and comparison of results from wind tunnel test data and simulations.