RIZK , Bashar

On asteroids, fractures develop due to stresses driven by diurnal temperature variations at spatial scales ranging from sub-millimetres to metres. However, the timescales of such rock fracturing by thermal fatigue are poorly constrained by observations. Here we analyse images of the asteroid (101955) Bennu obtained by the Origins, Spectral...

We found mini-craters on Bennu's boulders. We measure their sizes. We then use scaling laws to derive the strength and collisional lifetimes of C-type objects.

We manually mapped particles ranging in longest axis from 0.3 cm to 95 m on (101955) Bennu for the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) asteroid sample return mission. This enabled the mission to identify candidate sample collection sites and shed light on the processes that have...

When the OSIRIS-REx spacecraft pressed its sample collection mechanism into the surface of Bennu, it provided a direct test of the poorly understood near-subsurface physical properties of rubble-pile asteroids, which consist of rock fragments at rest in microgravity. Here, we find that the forces measured by the spacecraft are best modeled as a...

When rubble-pile asteroid 2008 TC3 impacted Earth on October 7, 2008, the recovered rockfragments indicated that such asteroids can contain exogenic material [1,2]. However,spacecraft missions to date have only observed exogenous contamination on large,monolithic asteroids that are impervious to collisional disruption [3, 4]. Here we report...