In 2009, NASA will purposely crash two spacecraft into one of the Moon's polar regions. The impacts should raise huge plumes of material, visible even to smaller telescopes on Earth. Dr. Anthony Colaprete (NASA Ames Research Center), the Principal Investigator for this intriguing mission, fills us in on why scientists believe there is water in deep craters at the Moon's poles and how the LCROSS mission plans to look for it in the plumes. Recorded January 21, 2009.