Scientists are considering repeatedly bombarding the moon with frozen water "comets" in order to sustain expeditionary crews and missions there. The project, called SLAM, is only in its proposal phase, but it appears to be one of the most efficient and cheapest ways to get usable water to the moon. Although there might already be water ice present on the moon, the SLAM project would send ice that is cleaner and more easily attainable. The ice payloads would not even need to be enclosed by a spacecraft on their journey, as a simple "thermal jacket" for the water would suffice. It will be a sad day for science when we send ice comets to the moon, only to have them fall off course and smash into some small village in Africa. The winter wonderlands that result, though? Magical.