Lunar scientists often use the term “water” to refer to both H2O and OH. And then, when the event was over, the H2O or OH went away.” “But when the Moon passed through one of these meteoroid streams, enough vapor was ejected for us to detect it. “The Moon doesn’t have significant amounts of H2O or OH in its atmosphere most of the time,” said Richard Elphic, the LADEE project scientist at NASA’s Ames Research Center in California’s Silicon Valley.

But debates continue about the origins of the water, whether it is widely distributed and how much might be present. There’s evidence that the Moon has water (H2O) and hydroxyl (OH), a more reactive relative of H2O. This discovery provides a potential resource for future exploration, and it improves our understanding the moon’s geologic past and its continued evolution. The LADEE spacecraft detects these water molecules as they enter the tenuous lunar atmosphere. For a sufficiently large impactor, this shock wave can breach the soil’s dry upper layer and release water molecules from the hydrated layer below. When a speck of comet debris strikes the moon it vaporizes on impact, creating a shock wave in the lunar soil. Scientists have discovered that water is being released from the moon during meteor showers. Benna is the lead author of the study, published in Nature Geosciences.

“We traced most of these events to known meteoroid streams, but the really surprising part is that we also found evidence of four meteoroid streams that were previously undiscovered,” said Mehdi Benna of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland Baltimore County. LADEE was a robotic mission that orbited the Moon to gather detailed information about the structure and composition of the thin lunar atmosphere, and determine whether dust is lofted into the lunar sky. Now, the team has found dozens of these events in data collected by NASA’s Lunar Atmosphere and Dust Environment Explorer. Models had predicted that meteoroid impacts could release water from the Moon as a vapor, but scientists hadn’t yet observed the phenomenon. The findings will help scientists understand the history of lunar water - a potential resource for sustaining long term operations on the Moon and human exploration of deep space.

Meteoroid that strikes earth