Ballistic Performance Model of Crater Formation in Monolithic, Porous Thermal Protection Systems

Monolithic, porous, thermal protection systems were used heavily on the Apollo command module, and they are currently being used on the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials may be highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on nominally 0.56 g/cm3 Avcoat ablator with phenolic flexible hexcore. An impact model that describes projectile dispersion in a monolithic material is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials.