HVI Ballistic Performance Characterization of Non-parallel Walls

The parallel, Double Wall, hypervelocity impact shield configuration has been heavily tested and characterized for ballistic performance for normal and oblique impacts for the ISS and other programs. However, in many locations with spacecraft designs, the rear wall cannot be modeled as being parallel or concentric with the outer bumper wall and in cases with a cylindrical outer wall, the effective non-parallel angle commonly varies as the outer wall impact location changes. This complicates micrometeoroid and orbital debris assessment of critical spacecraft components located within outer spacecraft walls. Based on a study combining hypervelocity impact testing and hydrodynamic impact simulations on multiple shield configurations including non-parallel first and rear walls, this paper provides equation adjustments for use with the double wall Ballistic Limit Equation (BLE) for a variety of impact speeds, non-parallel wall angles and impact obliquities.