Dynamic fragmentation of planetary materials: Sub-hypervelocity ejecta measurements and velocity scaling

• Ejecta tracking methods were used to study the impact response of planetary materials.
• Seventy-six experiments were performed for four materials at velocities of 25–500 m/s.
• Models were used to collapse mass and kinetic energy distributions among velocity.
• Median values were then used to collapse ejecta fields (vx vs. vy).
• Data is valuable when validating numerical models and understanding planetary impacts.

Ejecta velocity measurements were made during impacts into solid planetary materials. Ejecta velocity fields overlie each other when normalized by vmaxvmax, v50%mass, and v50%KE; these correspond to the maximum velocity and median values of mass and kinetic energy among ejecta velocities. Semi-empirical models were developed to provide predictive capabilities of 10th, 50th, and 90th percentiles of the distributions of mass, momentum and kinetic energy with respect to ejecta velocity. Lastly, a functional equation describing the probability density distribution of mass, momentum and kinetic energy among ejecta velocities was derived. Data and predictive models are valuable in the development and validation of numerical models, where comparison between experiments and simulations rely on well characterized measurements.