scientists have seen how the hydration of the Moon changes over the course of a day. NASA’s Lunar Reconnaissance Orbiter (LRO) has discovered that water molecules migrate across the dayside of the Moon, as the lunar day progresses. The study is published in Geophysical Research Letters.
The Moon is certainly dry and arid, but not as much as it was thought just a decade ago. Ice is present in craters that never get the light of the Sun, and water molecules are found in the lunar soil, the regolith. The team used LRO’s Lyman Alpha Mapping Project (LAMP) instrument to study water in the soil and, to their surprise, discovered that this sparse layer of molecules moves.
Data from the orbiter shows that the water is more common at higher latitudes. When the soil reaches its hottest temperatures, during the lunar noon, the heat is enough to allow the water molecules to break free and jump towards a cooler nearby region.
“Lunar hydration is tricky to measure from orbit, due to the complex way that light reflects off of the lunar surface,” co-author Dr. Michael Poston, member of the LAMP team at the Southwest Research Institute, said in a statement. “Previous research reported quantities of hopping water molecules that were too large to explain with known physical processes."
I’m excited about these latest results because the amount of water interpreted here is consistent with what lab measurements indicate is possible,” he added.
The study revealed how much energy is necessary to extract water from lunar soil, and this could be crucial for future astronauts missions. The study also revealed that while the solar wind might play a role in the formation of water on the Moon, what is observed builds up over time.
“These results aid in understanding the lunar water cycle and will ultimately help us learn about accessibility of water that can be used by humans in future missions to the Moon,” said Amanda Hendrix, senior scientist at the Planetary Science Institute and lead author of the paper.
“Lunar water can potentially be used by humans to make fuel or to use for radiation shielding or thermal management; if these materials do not need to be launched from Earth, that makes these future missions more affordable.”
NASA is planning to go back to the Moon and establish a permanent presence on our satellite within the next decade, so this information is vital.