In-Situ Cohesion Quantification and Sample Collection Through Electrostatic Lofting

The proposed investigation will explore the feasibility of collecting a regolith sample from the surface of an asteroid and measuring the cohesion of the regolith through electrostatic lofting. Due to the very low mass of asteroids, dust grains are bound to the surface primarily due to inter-granular cohesion, rather than gravity. Additionally, the surficial regolith grains are charged due to their interaction with the solar wind plasma. It has been hypothesized that dust grains may be detached from the surface of a small body simply due to the electrostatic force. We propose to use the physics of electrostatic lofting to characterize the cohesion of the surficial regolith and collect sample of an undisturbed small body surface. We propose to evaluate the feasibility of cohesion measurement and sample collection by an instrument that will be able to accurately control its distance above the surface and its electric potential. By changing its distance from the surface and electric potential, the instrument will change the local plasma environment. When the electrostatic force (produced by the interaction of the grain charge with the local electric field in the plasma sheath) is sufficient to overcome gravity and cohesion, dust grains will detach from the surface and approach the instrument. Through accurate knowledge of the instrument's position and potential, and the size of the grains lofted, it is possible to calculate the cohesion between the surficial dust grains. Additionally, the grains may adhere to the spacecraft, providing a novel, controllable method of sample collection. This technology is currently at TRL 2. We will bring this technology to TRL 4 by the end of the performance period. More »