Learn about an instrument onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft that looks for water on the Moon. Hear how the Lunar Explorer Neutron Detector (LEND) measures the quantity of slow and fast neutrons to collect information about the presence of hydrogen and the possibility of water on the Moon. Animations show how cosmic rays knock neutrons free from atoms in the Moon's soil and how the hydrogen content of the soil affects the speed of these neutrons.

This video is available in both English and Spanish audio with closed captions.