Novel Fragment Aerodynamic Models over Entire Velocity and Altitude Range

A novel method is proposed to model the aerodynamic lift and drag coefficients for complex fragment shapes resulting from the impact of Missile Defense Agency (MDA) interceptors with target vehicles. The force coefficients are needed for the entire spectrum of flight velocities and impact altitudes ranging from low-earth orbit to near-ground. Our Phase I approach considers a high altitude model (LEO to 45 km) and a low altitude model (45 km to 0 km). In the upper high altitude region we build upon previously successful models and bridge the free molecular regime and the continuum regime with truly unique functions derived from actual re-entry flight data. In the lower altitude region, we model the individual fragments with separate flow models for each region (subsonic, transonic, supersonic, hypersonic) while distinguishing the methods further by laminar or turbulent shear flow and by low or high angle of attack. The analysis will be guided by perturbations of generic shapes such as spheres, cylinders, plates, and needles in order to make use of existing data bases. The Phase II will emphasize the generation of coefficients as well as experimental and CFD validation and actual debris field simulations.