Presentation #512.03 in the session “Asteroid Hazards and Planetary Defense”.
Measuring the strengths of asteroidal materials is important for developing mitigation strategies for potential Earth impactors and for understanding properties of in situ materials on asteroids during human and robotic exploration. Few measurements of meteorite strength have been undertaken, as the samples have to be crushed. As such, catastrophic disruption modeling parameters have largely been obtained from studies of terrestrial analogs (e.g., basalt and concrete), or from studies limited to single specimens of meteorites. The few strength measurements performed leave open the question of statistical variation of meteorite strength, and the scale variation relevant to asteroid materials.
We are undertaking repeated destructive measurements of representative meteorites typical of common asteroids in near Earth orbit and have showed that the derived Weibull distribution projected to meter scales, overlaps the strengths determined from asteroidal airbursts and can be used to predict properties up to the 100-m scale (Cotto-Figueroa et al., 2016, Icarus, Vol. 277, pp. 73-77). Here, we present the results obtained from ten 1-cm cubes of the Aba Panu meteorite, which is an L3 ordinary chondrite that fell in 2018 over the Nigerian state of Oyo. The meteorite was recovered immediately after the fall and curated. The stones are very hard and difficult to cut and lack visible fractures and shock veins. During disruption, the Aba Panu meteorite showed axial crack initiation at the macro-scale at high strains and close to the ultimate strength, with rapid propagation into instant final failure by axial splitting. The implication is that Aba Panu meteorites are more homogeneous than the Allende and Tamdakht meteorites, exhibiting therefore higher strengths at meter-scales. This study will improve our understanding of the typical asteroid material environment and is a step towards placing fundamental constraints on disruption limits of asteroids.