Torque (C_M) coefficients for an ellipsoid a/b = 2 (left) and a/b = 0.5 (right) for complete diffuse reflection of the molecules (σ = 1) and T_d/T_∞ = 2. The range of the speed ratio s is chosen to cover a range of possible flow conditions. The speed ratio represents the ratio of the relative velocity of the gas-dust flow with respect to the thermal velocity of the gas molecules. The value s = 0.815 corresponds to the gas outflow conditions at the surface.