From Leonard David of Space.com:
SLAM needs no midcourse correction en route to the moon — nor does it need a spacecraft, for that matter. All that’s necessary is a thermal jacket for the water ice payload that’s flung by rocket booster toward any selected spot on the moon. ...
At lunar impact speeds, virtually all of the ice will come to rest less than 5 feet (1.5 meters) below the surface, if properly pre-fractured.
Need I say the idea is cool?