Experimental investigation of the impact fragmentation of blocks embedded in regolith


Corresponding author. E-mail: durda@boulder.swri.edu


Abstract– We present results of a set of impact experiments designed to examine the effects of impacts onto rocky blocks resting on and embedded within regoliths. The targets were approximately 500 g granodiorite blocks, struck with one-eighth inch aluminum spheres at nominal speeds of approximately 5 km s−1. The granodiorite blocks were emplaced in 20–30 grade silica sand to simulate an asteroidal or lunar regolith; block burial depths ranged from resting flush on the surface to submerged completely below the surface. We observe a trend for largest remnant mass to increase with block burial depth. Documentary still image and high-speed video of the resulting block fragments and surrounding regolith reveal new insights into the morphologies of blocks and secondary craters observed on asteroids like 433 Eros.