To get below the ancient lunar rocks, NASA crashed a rocket into the moon's south pole.

VOA: special.2009.12.30

This huge continent on the Earth's South Pole covers about fourteen million square kilometers.

VOA: special.2009.06.03

That project involves crashing a rocket stage into the moon's south pole.

VOA: special.2009.09.30

In a section on water in outer space we learn that there is a lake-size layer of ice on the moon's south pole, that Mars once had rivers, that there is steam in the sun's atmosphere.

FORBES: The Story Of Eau

The lunar crater named after Tycho Brahe, a 16th century Danish astronomer, near the moon's south pole, is 85km across.

ECONOMIST: Asteroid impacts

And, at a few spots around the moon's south pole, the reflections did indeed look like the sorts of echoes that would come from ice.

ECONOMIST: Creative destruction