Ballistic limit curves for non-spherical projectiles impacting dual-wall spacecraft systems

Ballistic limit curves for dual-wall spacecraft systems are typically developed using ground-based hypervelocity impact tests with spherical projectiles. However, most orbital debris particles are not spherical and can take any shape. Non-spherical projectiles can also be more damaging than equal mass spherical projectiles. Although some recent efforts have examined the effects of non-spherical projectile impacts, ballistic limit curves for non-spherical projectiles are still not available. This paper presents the results of a study in which numerical simulation methods were used to develop ballistic limit curves for a variety of non-spherical projectile shapes impacting a typical dual-wall spacecraft configuration. Ballistic limit curves for non-spherical projectiles are presented and compared against that for spherical projectiles impacting the same wall system. It is found that long cylinder and long cone projectiles have a higher penetrating capability than all other projectile shapes considered, including spherical projectiles. The implication is that if a spacecraft wall system is designed using spherical projectile-based ballistic limit curves, the design will likely be non-conservative.