Hypervelocity impacts of orbital debris on an advanced heat shielding material: comparison of Ouranos computations to experimental results

On behalf of the European Space Agency, Centre d'Etudes de Gramat (CEG) has performed works aiming at modeling the behavior under hypervelocity impacts of an Aerospatiale exp 1 developed composite material called AQ60. A model including a multiphase equation of state and a porous material behavior has been chosen. It is based on the description of the state surface of the dense material, its compaction curve and a thermal softening curve. The parameters related to the state surface and the thermal softening curve have been determined from literature, while the compaction curve was obtained from CEG experiments. Perforation and penetration experiments by hypervelocity impact were realized on AQ60 with a CEG double stage light gas gun. These highly instrumented experiments have provided valuable information to analyze the material behavior under hypervelocity impacts. Moreover, the typical cratering processes highlighted confirm the phenomenological analysis that originally directed the model choice. Finally, the chosen model has been implemented in the OURANOS hydrocode for validation by hypervelocity impact experiments. Computations show this tool is able to predict the effects of a hypervelocity impact on AQ60 with good accuracy. Since this material is frequently designed for thermal insulation of spacecraft, this numerical tool will allow evaluation of damage resulting of very high velocity impact of meteoroids or orbital debris on AQ60.