November 16
Spacecraft Thruster Plume-Surface Interaction for Characterization of Hazardous Asteroids
Speaker: Dr. Ronald Ballouz, JHU APL
Abstract: In the event of the discovery of a hazardous asteroid, spacecraft reconnaissance can provide valuable information on the asteroid’s physical properties in order to formulate an optimized mitigation strategy. Spacecraft exploration has shown that NEAs are covered by a layer of regolith. The near surface and interior geotechnical properties of this regolith, such as its strength, density, and porosity, are critical to the design of planetary defense strategies. However, the geotechnical properties of potentially hazardous asteroids (PHAs) are generally poorly known, and can only reliably be estimated through in situ reconnaissance and surface interaction. The Hayabusa2 mission demonstrated how to estimate regolith strength with the use of a small carry-on impactor (SCI) by forming a crater on asteroid Ryugu. Similarly, during its sampling of asteroid Bennu, the OSIRIS-REx spacecraft excavated a crater through gas and thruster fire. Furthermore, tracking of naturally ejected Bennu particles enabled the measurement of the asteroid’s high-order gravity field and the surface’s coefficient of restitution. If the gas-excavation process can be better understood, rendezvous asteroid missions have the potential to use their on-board thrusters as a tool for understanding near-surface and interior properties of mission targets. Unlike traditional impact experiments, crater formation through gas firing is far less studied, and it is not immediately clear whether thrusters can be used to reliably obtain an estimate of regolith geotechnical properties. In this talk, I’ll outline a framework with which spacecraft thrusters can be used as a robust tool for asteroid characterization.
Host: Ben Sharkey