Ejecta characterization during hypervelocity impacts in geomaterials

Characterizing the ejecta generated from projectile penetration events is essential in defense and planetary sciences applications. For example, understanding the behavior of the debris cloud during missile strikes can help us minimize collateral damage. Studying the ejecta generated from both man-made and natural impacts on unexplored planetary bodies can reveal their composition and control their orbit changes during planetary defense exercises. In this work, we develop novel experimental diagnostics to investigate the full 3D velocity distribution and size of the ejected fragments during hypervelocity impacts on sandstone and concrete. We use a laser sheet setup during the high-speed video imaging of the impact event and image tracking algorithms to obtain the out-of-plane velocity component of the fragments. We also use an ejecta-catching system, which traps some of the ejected fragments from which a particle size distribution can be obtained. Furthermore, we analyze the ejecta characteristics of materials that have very different microstructures, as well as the different impact velocities, projectile sizes, and porosity of the target sample. This study is a step forward in understanding the intricate mechanisms that occur during ejecta generation and release during the dynamic impact on brittle geomaterials.