Boulder Retrieval Forces from an Asteroid
Working through Applied Mechanics Associates, the Coupi DEM is being used to assist NASA Langley engineers in estimating the forces that appear during landing a spacecraft on an asteroid and the forces required to extract a boulder from the surface of an asteroid with unknown surface regolith properties. This work is in support of NASA’s Asteroid Redirect Mission (ARM) planning team. The ARM is a robotic mission to a near- Earth asteroid to retrieve a 1 m to 5 m boulder from the surface and move it to a lunar orbit for astronauts to explore. The Coupi DEM provides design information to the NASA engineers to help in designing the mission lander and boulder extraction methodology. This work utilized the Coupi DEM’s JKR particle cohesion formulation to simulate the direct shear and tension strength properties of the DEM particles to match estimated properties of asteroid regolith derived from tests done during Apollo lunar missions and from theoretical studies.
Figure 1: DEM simulation of a tension test to determine the bulk cohesion strength of the particle bed representing asteroid regolith.
Figure 2: DEM simulation of a pulling a boulder from an asteroid surface showing an elliptical boulder resting on a cohesive particle bed (top panel) and after being pulled upward from the particle bed surface (bottom panel).
This is ongoing work and related information can be found at:Kulchitsky, A. et al. 2016. Resistance forces during boulder extraction from an asteroid, Acta Astronautica, 127:424-437