TARGET POROSITY EFFECTS IN IMPACT CRATERING AND COLLISIONAL DISRUPTION

We present the results of a series of eight experimental hypervelocity impacts of soda lime glass projectiles into porous sintered aggregate glass targets with varying strengths and densities. Increased target porosity leads to deeper crater penetration, lower spall velocities, and greater localization of the impact damage. Rear surface spallation is also greatly reduced in porous targets. Estimates of the specific energy required to destroy targets of varying porosity indicates that this threshold is proportional to (1-porosity)-3.6, much greater than the dependence on unconfined compressive strength, and implying that the lifetimes of porous meteoroids and interplanetary dust particles against collisional disruption are longer than previously predicted. These experiments also produced melt-lined agglutinate crater pits, often well preserved despite total disruption of the target. © 1993 by Academic Press, Inc.