SMU Physics Department Speaker Series - Dr. Ron Ballouz, Ph.D. (JHU Applied Physics Laboratory)
Channel: Stephen Sekula
Date: 2022-04-05

Near-Earth asteroids (NEAs) pose both a hazard and an opportunity. Their relative velocities with Earth are sufficiently large that an impact by an asteroid larger than 100 m would cause a near-global catastrophe. On the other hand,  asteroids preserve the earliest stages of Solar System formation, and telescopic observations have revealed that asteroids may represent a significant reservoir of rare metals and space-accessible volatiles. The utilization of asteroid resources may enable the future expansion of the human presence outwards into the Solar System.
Spacecraft exploration of asteroids has shown that their surfaces are composed of both fine particles and larger meter-scale boulders. An asteroid’s surface history is determined, in large part, by its strength against collisions with other objects. Furthermore, for asteroid sample-return missions, characterizing the strength of the surface and near surface is critical for ensuring spacecraft safety and sampling success. Prior to the Hayabusa2 and OSIRIS-Rex missions to the asteroids Ryugu and Bennu, it had not been possible to assess directly the impact strength of the regolith and boulders that constitute the building blocks of a rubble-pile asteroid.


In this talk, I will discuss how we used a combination of remote observations of asteroid Bennu and the OSIRIS-REx spacecraft´s surface interaction on October 2020 to gain knowledge of the strength of both the surface layer and meter-scale boulders. I will then place these results in the context of the surface evolution and interior structure of Bennu and NEAs, in general. Finally, I will show how these findings may be used to interpret upcoming next-generation population surveys of NEAs, providing a glimpse into the strength and interior properties of the least discovered and most populous Potentially Hazardous Asteroids.