Nonlinear dynamic modeling and simulation of an atmospheric re-entry spacecraft

Abstract

This paper discusses the dynamic modeling and simulation techniques for the X-38 re-entry spacecraft, a prototype crew return vehicle (CRV) for the international space station (ISS). A general simulator for atmospheric re-entry dynamics (GESARED) was developed in the Matlab/Simulink environment. The 6 degree-of-freedom re-entry flight dynamics were modeled to achieve minimum restrictions and singularities. Quaternion representation of vehicle attitude was used to avoid computational singularities in angular kinematic model equations. The Earth's atmosphere, Earth's shape and gravitational potential were modeled appropriately. The vehicle's aerodynamic characteristics, navigation sensors, and the actuator dynamics were also modeled and implemented. Several numerical simulation tests and analyses were conducted to evaluate the performance of the model equations and the simulator.