Program for the Estimation of Spacecraft Aerodynamic Properties

A numerical procedure for calculating free-molecular aerodynamic properties of spacecraft is revisited and improved using a modern computer program, Matlab 2007. This program allows the user to model a spacecraft from geometric shapes which are divided into elemental panels of approximate equal area to conserve resolution. The forces on exposed elements are summed across the entire geometry. The methods for determining exposed panels have been improved with the utilization of array algebra to improve processing time. The fidelity of the data is tested by application to the geometry of the Mars Reconnaissance Orbiter. The resulting data are compared with Direct Simulation Monte Carlo predictions. Additional case studies serve to inspect implications of geometry design versus output accuracy and processing speed.