Ejecta fragmentation in impacts into gypsum and water ice

Using the light gas gun at the Open University’s Hypervelocity Impact facility, a series of impact experiments exploring impacts into water ice and gypsum have been performed. Fragmentation of solid ejecta was recorded using two different methods, analysed and compared with the total ejecta. Preliminary results show that the size distribution of the ejecta fragments from water ice is very similar to those from gypsum. These results also represent a step towards a better understanding of ejecta fragmentation in geological materials, including icy surfaces in the Solar System.

► Size distribution of impact induced solid ejecta from gypsum and water ice investigated in impact experiments.
► Size distribution of the ejecta fragments from water ice is similar to those from gypsum.
► The fragmentation seems not to be strongly dependent on projectile material, size, velocity, or incident angle.
► Better understanding of ejecta fragmentation in geological materials, used as icy planetary surface analogues.