  We present recent improvements in the simulation of regolith sampling
processes in microgravity using the numerical particle method smooth particle
hydrodynamics (SPH). We use an elastic-plastic soil constitutive model for
large deformation and failure flows for dynamical behaviour of regolith. In the
context of projected small body (asteroid or small moons) sample return
missions, we investigate the efficiency and feasibility of a particular
material sampling method: Brushes sweep material from the asteroid's surface
into a collecting tray. We analyze the influence of different material
parameters of regolith such as cohesion and angle of internal friction on the
sampling rate. Furthermore, we study the sampling process in two environments
by varying the surface gravity (Earth's and Phobos') and we apply different
rotation rates for the brushes. We find good agreement of our sampling
simulations on Earth with experiments and provide estimations for the influence
of the material properties on the collecting rate.
