Planets and Moons  ID: 4057

LEND Looks for Water at the South Pole

Since Lunar Reconnaissance Orbiter (LRO) entered lunar orbit in 2009, its neutron detector, LEND, has been counting the neutrons coming from the Moon's surface.

Neutrons are created when galactic cosmic rays strike atoms in the lunar regolith. These neutrons bounce from atom to atom like billiard balls, losing energy with each collision. Along the way, some of these neutrons escape into space, where LEND can detect them.

The presence of hydrogen in the lunar soil reduces the number of neutrons that escape. To map out likely deposits of water ice, LEND scientists look for this deficit of neutrons in the epithermal (medium) energy range.

If the deficit were simply due to random fluctuations, the hydrogen map would never coalesce into a sharp image, but as this animation shows, the map of epithermal neutron deficit at the south pole of the Moon improves over time and converges on particular spots. These include especially strong signals in the permanently shadowed parts of Cabeus and Shoemaker craters, where ice would be completely shielded from the sun. But LEND and other missions have found signs of water in places that aren't permanently shadowed while apparently excluding some places that are, both of which are surprising and exciting discoveries.



Visualization Credits

Ernie Wright (USRA): Lead Animator
Silvia Stoyanova (USRA): Producer
Dan Gallagher (USRA): Producer
Tim McClanahan (NASA): Scientist
John Keller (NASA/GSFC): Scientist
Please give credit for this item to:
NASA's Goddard Space Flight Center Scientific Visualization Studio

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LRO (Lunar Reconnaissance Orbiter)

Data Used:
LRO/LOLA/Digital Elevation Map
SPICE Ephemerides
Note: While we identify the data sets used in these visualizations, we do not store any further details nor the data sets themselves on our site.

This item is part of these series:
The Moon
LRO - Animations

SVS >> Elevation data
SVS >> Lunar
SVS >> Moon
SVS >> Hyperwall
SVS >> Neutron
SVS >> Integration
SVS >> Lunar Reconnaissance Orbiter
NASA Science >> Planets and Moons