Water on the Moon: What Does it Mean?

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The Moon has been turned upside down. Figuratively, of course. La Luna still orbits and phases as it always has, but we are now looking at the moon anew. From this day forward we know the chemistry of the Moon is different than what we have thought for decades, the geology might vary from what is in textbooks today, and the physics of how the solar wind interacts with a rocky body without an atmosphere has implications not yet fully investigated. So, what does this mean for our future human and robotic exploration of our closest companion in space?

“The Moon continues to surprise us,” said Carle Pieters, principal investigator for the Moon Mineralogy Mapper (M cubed) at Thursdays press conference. “Widespread water has been detected on the surface of the Moon. You have to think outside of the box on this. This is not what any of us expected decades ago.”

Immediately, space enthusiasts’ thoughts turn to how finding water on the Moon will make future exploration there so much easier.

“Scientists thought they knew fairly accurately what the surface of the moon was like and these results show that they didn’t – or at least not completely,” said Dr. Chris Welch, astronautics and space systems expert at Kingston University in London. “Finding so much more water could make living on the moon much easier in the future…If there is water on the moon – in whatever form – then we have a potential reservoir that could be used for drinking or to make into hydrogen and oxygen which could be used as rocket propellant. Also, of course, we could use the oxygen to breathe.”

But the message the scientists wanted everyone to take away from today’s press conference is that a combination of water (H2O) and hydroxyl (OH) that resides in upper millimeter of the lunar surface doesn’t actually amount to much. The average amount of water, if extracted, is about a quart (1 liter) of water per ton of surface soil, or about 16 ounces (.5 liters) of water might be present for every 1,000 pounds (450 kg) of surface soil near the moon’s poles. For soil near the equator, only about two tablespoons of water is believed to be present in every 1,000 pounds (450 kg).

“That is truly astounding, and generating much excitement,” said Jim Green, director of the Planetary Science Division at NASA. “But please keep in mind that even the driest deserts on the Earth have more water than are at the poles and the surfaces of the moon.”

So maybe this water on the Moon is not such a big deal.

But there’s still the very real possibility that there could be water ice underneath the regolith on the Moon or buried deep within craters at the poles. Fairly recent (within the past million years) impact craters on the moon were found to have ejecta “rich” with water and hydroxyl, according to M cubed data, which implies recently those molecules are buried under the surface.

Plus the scientists hinted at data showing Goldschmidt Crater at the Moon’s north pole could be filled with water ice.

Additionally, what the scientists at today’s briefing found most astonishing about the new findings is that the water and hydroxyl show up at all latitudes, even at the equator in sunlight, where it is quite hot, and that there are a wide variety of hydroxyl bearing minerals at the surface. This is telling us there are some dynamic processes happening on a moon we thought to be bone dry and basically dead.

There appears to be a cycle of water being created and lost during a lunar day. Without an atmosphere, the moon is exposed to solar wind, which includes hydrogen ions. The hydrogen is able to interact with oxygen in lunar soil to create water molecules. The water appears to be created at night on the Moon, lost during the “hottest” parts of the two-week lunar day; then as it cools near evening, the cycle repeats itself. So, regardless of the type of terrain on the Moon, the entire surface of the moon will be hydrated at least for part of the day. The scientists said similar hydration effects may be present on any body in our solar system that doesn’t have an atmosphere, including asteroids and Mercury.

Those implications are huge for our explorations of other moons and worlds.

But back to the Moon. “Before this press conference, it was thought to be impossible to have water on the surface of the Moon in hot sunlight, especially on the surface at the equator,” said Roger Clark, with the M cubed and Cassini mission.

Could water be a renewable resource on the Moon? If the water is constantly being created, could a devise be built to extract or collect the water? Easy availability of water would have an immense impact on any future human exploration on the Moon, be it brief sorties or permanent colonies.

This is intriguing,” said Pieters, “but we need to go back and re-determine this silicate surface and the vacuum around it. This is an environment we know very little about, and the physics is in its infancy.”

Discussing the implications, Pieters said first, the source of the water needs to be determined, whether it is actually from the solar wind, comets, meteorites, possibly an outgassing from the interior. “There are fundamental questions we need to understand about this silicate body,” she said. “Clearly this has to be a marriage between geology and space physics.”

And what about the “follow the water” mantra NASA has been following in regards to Mars? Could the “where there’s water, there’s life” hypothesis pertain to the Moon? Is there water on the Moon? While these new details about the Moon are groundbreaking, Welch does not believe the new findings show there is or could once have been life on the moon, but he says further research is needed. “There need to be more detailed science missions, preferably with astronauts landing on the moon, to analyse the soil in space.”

Certainly, the upcoming LCROSS impact on the Moon’s south pole will be watched with even greater interest. But what about future exploration?

Will this impel the Constellation Program to continue as planned with a return to the Moon? The Obama administration has some big decision to make in regards to NASA, and it’s hard to imagine this new information about the Moon won’t have some impact on the future path the space agency will take.

We can only hope this news brings more public and congressional interest in NASA’s future.