Accurate potential energy curves are calculated for the sulfur anion, S-(P-2), interacting with a helium atom, both in the presence and absence of the spin-orbit interaction. Spectroscopic parameters and transport coefficients are calculated from the potential energy curves, and discussed in the light of available experimental data. It is concluded that there is a need for more accurate experimental data. (c) 2005 Elsevier B.V. All rights reserved.