The lunar south pole is where humanity plans to build its first permanent outpost but we still don't fully understand what lies beneath the surface. A new study has used radar to peer below the ground in one of the Moon's most complex and battered regions and what it's finding raises important questions about the geological minefield that future astronauts will be navigating. Ancient impacts, frozen melt sheets, and billions of years of overlapping debris may complicate our plans more than we thought.