How to effectively get into a polar orbit and land near (in) a S. polar crater and look for sublimated water (i.e. hydrogen). So coast to the Lagrangian pt between earth and moon; then accelerate into a polar orbit. Land a rover in Mars-like manner. Use a laser, at a distance, to sublimate any water ice in crater wall. Then take a spectrum of any such sublimated water (i.e. hydrogen).