On Second Thought, the Moon’s Water May Be Widespread and Immobile

If the Moon has enough water, and if it’s reasonably convenient to access, future explorers might be able to use it as a resource. (Credit: NASA’s Goddard Space Flight Center)

By Elizabeth Zubritsky
NASA’s Goddard Space Flight Center

GREENBELT, Md. (NASA PR) — A new analysis of data from two lunar missions finds evidence that the Moon’s water is widely distributed across the surface and is not confined to a particular region or type of terrain. The water appears to be present day and night, though it’s not necessarily easily accessible.

The findings could help researchers understand the origin of the Moon’s water and how easy it would be to use as a resource. If the Moon has enough water, and if it’s reasonably convenient to access, future explorers might be able to use it as drinking water or to convert it into hydrogen and oxygen for rocket fuel or oxygen to breathe.

“We find that it doesn’t matter what time of day or which latitude we look at, the signal indicating water always seems to be present,” said Joshua Bandfield, a senior research scientist with the Space Science Institute in Boulder, Colorado, and lead author of the new study published in Nature Geoscience. “The presence of water doesn’t appear to depend on the composition of the surface, and the water sticks around.”

The results contradict some earlier studies, which had suggested that more water was detected at the Moon’s polar latitudes and that the strength of the water signal waxes and wanes according to the lunar day (29.5 Earth days). Taking these together, some researchers proposed that water molecules can “hop” across the lunar surface until they enter cold traps in the dark reaches of craters near the north and south poles. In planetary science, a cold trap is a region that’s so cold, the water vapor and other volatiles which come into contact with the surface will remain stable for an extended period of time, perhaps up to several billion years.

The debates continue because of the subtleties of how the detection has been achieved so far. The main evidence has come from remote-sensing instruments that measured the strength of sunlight reflected off the lunar surface. When water is present, instruments like these pick up a spectral fingerprint at wavelengths near 3 micrometers, which lies beyond visible light and in the realm of infrared radiation.

But the surface of the Moon also can get hot enough to “glow,” or emit its own light, in the infrared region of the spectrum. The challenge is to disentangle this mixture of reflected and emitted light. To tease the two apart, researchers need to have very accurate temperature information.

Bandfield and colleagues came up with a new way to incorporate temperature information, creating a detailed model from measurements made by the Diviner instrument on NASA’s Lunar Reconnaissance Orbiter, or LRO. The team applied this temperature model to data gathered earlier by the Moon Mineralogy Mapper, a visible and infrared spectrometer that NASA’s Jet Propulsion Laboratory in Pasadena, California, provided for India’s Chandrayaan-1 orbiter.

The new finding of widespread and relatively immobile water suggests that it may be present primarily as OH, a more reactive relative of H2O that is made of one oxygen atom and one hydrogen atom. OH, also called hydroxyl, doesn’t stay on its own for long, preferring to attack molecules or attach itself chemically to them. Hydroxyl would therefore have to be extracted from minerals in order to be used.

The research also suggests that any H2O present on the Moon isn’t loosely attached to the surface.

“By putting some limits on how mobile the water or the OH on the surface is, we can help constrain how much water could reach the cold traps in the polar regions,” said Michael Poston of the Southwest Research Institute in San Antonio, Texas.

Sorting out what happens on the Moon could also help researchers understand the sources of water and its long-term storage on other rocky bodies throughout the solar system.

The researchers are still discussing what the findings tell them about the source of the Moon’s water. The results point toward OH and/or H2O being created by the solar wind hitting the lunar surface, though the team didn’t rule out that OH and/or H2O could come from the Moon itself, slowly released from deep inside minerals where it has been locked since the Moon was formed.

“Some of these scientific problems are very, very difficult, and it’s only by drawing on multiple resources from different missions that are we able to hone in on an answer,” said LRO project scientist John Keller of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington, D.C. JPL designed, built and manages the Diviner instrument.

Read the paper in Nature Geoscience: http://dx.doi.org/10.1038/s41561-018-0065-0

  • Michael Halpern

    A colony needs to be self sufficient the moon cant be, Mars can, simple choice between the moon and Mars

  • Michael Halpern

    if you want energy dense nuke to live off of, the fuel will last 6 months before you need to replace it.

  • ThomasLMatula


    No. The dust storms occur because the dust on Mars is so fine. And the composition of the atmosphere doesn’t effect its density. FYI.

    https://www.nasa.gov/feature/goddard/the-fact-and-fiction-of-martian-dust-storms

    The Fact and Fiction of Martian Dust Storms

    https://www.space.com/30663-the-martian-dust-storms-a-breeze.html

    ” With an understanding that wind force is a function of atmospheric
    density as well as velocity, calculations show the speed of a 60-mph
    storm on Mars would feel more like 6 mph (9.6 km/hr), Smith said.”

  • ThomasLMatula

    Whatever gas is available on the Moon. Oxygen from lunar soil would probably work.

  • Michael Halpern

    Which as you can make turbines in situ, making it a valid power supply isn’t a problem it’s not finite like nuclear easier to expand than solar

  • Michael Halpern

    Setting up hundreds of turbines is easier and more economical than bringing a miniature nuclear reactor for the same amount of power

  • ThomasLMatula

    No, that is incorrect. There is a new generation of small commercial nuclear reactors being developed that will have spinoffs that will work well on the Moon.

    https://energy.gov/ne/nuclear-reactor-technologies/small-modular-nuclear-reactors

    Advanced Small Modular Reactors (SMRs)

    https://www.forbes.com/sites/jamesconca/2017/03/16/nuscales-small-modular-nuclear-reactor-keeps-moving-forward/

    I could see why it might not be impossible to use nuclear reactors on Mars, since a dust storm could spread any contamination over a wide area. But without an atmosphere there is no such risk on the Moon.

  • Michael Halpern

    No to back pressure it

  • Michael Halpern

    How are you going to extract the oxygen from lunar soil molten salt extraction for aluminum is decades off and traditional aluminum refining needs petcoke (carbon not available on Luna)

  • Michael Halpern

    I am referring to kilopower as well, not good for more than 4 people

  • Michael Halpern

    No carbon on the moon so we can’t do squat there with known techology

  • ThomasLMatula

    No, the containers will be reused, just as on Earth. If they are stressed for high-G acceleration it won’t take a lot of energy to brake them for a lunar return. Stop thinking in terms of how NASA launches things from Earth.

  • ThomasLMatula

    You haven’t listen to what the Planetary Protection Office has been saying.

  • ThomasLMatula

    A colony is a settlement that is the servant of its founding nation. A settlement is politically and economically free. Note, not self-sufficient, but able to import what it doesn’t produce. The last human societies that are self sufficient are the hunter-gathers.

  • ThomasLMatula

    But none will have enough wind to produce any power. Plain and simple.

  • ThomasLMatula

    And you just bring it from Earth. That is how an economy works. You export what you produce to import what you need.

  • ThomasLMatula

    You did not read the articles did you. These are not NASA style RTG, but reactors that are large enough to power a small city. You really need to start seeing space from the perspective of 21st Century economics, not 1970’s Whole Earth models…

  • ThomasLMatula

    So you import it from Earth, just as we import coffee and bananas. If you want to live independent of the global economy you need to join a commune in the desert, not settle space. You sound like the L-5ers who used to publish in the Whole Earth Catalogs 🙂

  • redneck

    The problem with Mars above all is the time value of money. A ship that can only deliver every other window must recoup its’ entire value on every trip when interest is included. A reusable Lunar ship can run 50 to 100 times during each Mars trip by a ship that is almost by definition, far more expensive. I was once told that the rocket equation makes a good start, but the financial equation makes a better finish.

    A relatively simple and small Lunar ship could land dozens of financially risky prospecting missions for the price of one Mars crap shoot. Mars may well eventually be our second planetary home, but only after the financial numbers close. Until then, it is a distraction of scientific interest only.

  • Michael Halpern

    The goal is to important almost nothing

  • Michael Halpern

    Yes they will

  • Michael Halpern

    Yes and data/information service is your biggest export in any space venture

  • Michael Halpern

    Then you need a crap ton of delta v to get them back to the moon no point in getting propellant from the moon in the first place

  • The term “industrial” typically connotes large buildings with lots of pipes and heavy machinery. That’s not what’s needed on the Moon in order to produce usable amounts of water such as refueling a lander in a reasonable period of time.

    Here’s what “industrial” shows up when typing it into Google Images:
    https://www.pexels.com/search/industrial/

    …and here an illustration of the minimal amount of hardware it would take to refuel a lander from Cabeus-concentration of icy regolith:
    http://www.developspace.info/images/cl1.png

  • Lunar prop would be useful for transporting crew from EML to Lunar and back. The market demand for this transportation service would initially be for NASA to fulfill the current policy, then a broad demand for international, suborbital lunar exploration, then for private, wealthy individual who wish to be a part of the historic founding of humanity’s first permanent foothold off Earth. Reduced transportation costs after that will then make other, material-based business plans (eg PGMs or something) possible.

  • Michael Halpern

    Assuming you can set up large scale water extraction, sure but because of resource disparity between Earth and Luna setting up any form of industry will require likely decades of material science development, and much of that will only be useful on Earth when recycling is not enough for things like aluminum, with Mars your industry will be chemically similar if not near identical to Earth, you would have to substitute fossil fuels and introduce oxygen more artificially, but that can lead to technology immediately useful on Earth, coal free virgin steel for instance

  • > what advantage economically does sourcing prop from Luna bring

    For lunar ascent prop, to get that from Earth requires launching a FH-class rocket for every about 10 tonnes. To get that 10 tonnes from lunar resources would require a month’s cycle of an Ice Harvester that had been previously delivered plus the operations cost and amortization of the hardware and spare parts. Might it be more cost-effective for a month’s duty cycle of the Ice Harvester compared to launching another rocket? Possibly.

  • Are you aware of all of the LCROSS results?

  • Right. When one is able to harvest propellant-quantities of water ice, not only does one have propellant but breathable oxygen, water for sanitation and food, and carbon and nitrogen for use by a base that recycles these things. If also extending crew stay, relatively quickly the amount of mass that would need to be launched to support the base would be something like 15% or less. In the relative near term we would be launching people, electronics, and certain items and materials hard to make or source on the Moon.

  • Michael Halpern

    There is a question of how useful hydrolox is, it lacks the density for reusable rockets, and isn’t great for most station keeping, limiting it to stuff that uses a lot of ∆v which may be Astroid mining and outer solar system exploration

  • Michael Halpern

    Everything i have found is that there is a very very very small trace amount of carbon on the moon

  • Michael Vaicaitis

    First of all, that picture doesn’t really convey the 2 km deep vertical cliffs with house sized boulder field across the crater floor, in perpetual darkness, in vacuum, at -250.
    Second, this latest study (based on the original low resolution data) implies that there may indeed be no H2O at all, and it might well be all OH. All of which would require large scale excavation and large buildings and huge pipes, and heavy machinery, all supplied by many hundreds of megawatts of nuclear power. So yes, the vast industrial scale mining effort is far more likely than the “locate it with a couple of torches and sweep it up with a dustpan and brush” scenario you envisage.
    Third, nobody really wants the stuff, except perhaps for a handful of visiting scientists, when we eventually get round to sending them – the passengers and cargo embarking to Mars are on Earth, not on the Moon.

  • Michael Vaicaitis

    But the people, cargo, and Mars transport are all in LEO – there won’t be anyone departing from lunar orbit regardless of whether or not the propellant is 20% cheaper. And what’s with the “FH-class”? – BFS is going to be refuelled by BFS Tankers.
    You little WALLE Ice Harvester, harvesting the ice that probably isn’t there in some of the most extreme terrain and conditions in the solar system will need to be producing hundreds or thousands of tonnes a day to be of any use (one BFS takes 1100 tonnes of prop) – it will need to be “industrial scale”.

  • Does this latest analysis negate the LCROSS findings in which 5.6% of the icy regolith was crystalline water ice plus organics?

    https://www.nasa.gov/mission_pages/LCROSS/main/prelim_water_results.html

    https://www.universetoday.com/76329/water-on-the-moon-and-much-much-more-latest-lcross-results/

  • Not all permanently-shadowed craters have 2 km deep vertical cliffs. Modern VTVL vehicles image obstacles and land accordingly. Perpetual darkness is implied by the picture (for practical reasons one has to see the equipment). Vacuum is implied as this is the surface of the Moon. The known cryogenic temperatures are acknowledged and addressed with the use of vehicle body heat and the use of aluminum for those parts that contact the surfaces.

    Many countries would like to send their national astronauts to explore the Moon on behalf of their citizens. Ascent and descent propellant could be used to support that demand.

  • ThomasLMatula

    LOL And that is the basic problem with Mars advocates, their rejection of logic and economics.

  • ThomasLMatula

    You didn’t read those articles did you?

  • ThomasLMatula

    Yes, it’s the proximity that counts. Mars will only be the domain of science for decades into the future.

  • ThomasLMatula

    Except that there won’t be any passengers going to Mars, other than a handful of Astronauts, for next 50 years or so. The Planetary Protection folks are not going to allow humans, and their 10,000 plus microbes, anywhere near it for at least that long. Yes, it’s stupid, but they want to prevent contimantion of it. This is the 800 pound Gorilla that Mars advocates keep ignoring.

  • Michael Halpern

    Listen because of short nights you don’t need nukes on mars at all wind is mainly to reduce storage requirements for dust storms as you have plenty of space for solar the reduced sunlight isn’t a problem you don’t have 14 day nights like on the moon only slightly longer than that of earth making it an easy primary power source

  • Michael Halpern

    Less i have to send there the more guaranteed my returns are over time,

  • Michael Halpern

    Colonization is the ultimate long term investment

  • Michael Halpern

    Early on Mars colony would make money via product placement and celebrity status of colonists, after that taking advantage of high data rate to the belt to aid in astroid mining

  • Michael Vaicaitis