AERODYNAMICS OF THE SHUTTLE ORBITER AT HIGH-ALTITUDES

The high-altitude, high-Knudsen-number aerodynamics of the Shuttle Orb iter are computed from low Earth orbit down to 100 km using three-dime nsional direct simulation Monte Carlo and free-molecule codes. Results are compared with the latest Shuttle aerodynamic model, which is base d on in-flight accelerometer measurements, and bridging-formula models . Good comparison is observed, except for the normal-force and pitchin g-moment coefficients. The present results were obtained for a generic Shuttle geometry configuration corresponding to a zero deflection for all control surfaces.