Presence of water confirmed on the moon


The image shows the distribution of surface ice at the Moon’s south pole (left) and north pole (right), detected by NASA’s Moon Mineralogy Mapper instrument. Blue represents the ice locations, plotted over an image of the lunar surface, where the gray scale corresponds to surface temperature (darker representing colder areas and lighter shades indicating warmer zones). The ice is concentrated at the darkest and coldest locations, in the shadows of craters. This is the first time scientists have directly observed definitive evidence of water ice on the Moon’s surface. Credit: NASA

Water Ice confirmed at the moon’s poles

In the darkest and coldest parts of its polar regions, a team of scientists has directly observed definitive evidence of water ice on the Moon’s surface. These ice deposits are patchily distributed and could possibly be ancient. At the southern pole, most of the ice is concentrated at lunar craters, while the northern pole’s ice is more widely, but sparsely spread.

A team of scientists, led by Shuai Li of the University of Hawaii and Brown University and including Richard Elphic from NASA’s Ames Research Center in California’s Silicon Valley, used data from NASA’s Moon Mineralogy Mapper (M3) instrument to identify three specific signatures that definitively prove there is water ice at the surface of the Moon.

M3, aboard the Chandrayaan-1 spacecraft, launched in 2008 by the Indian Space Research Organization, was uniquely equipped to confirm the presence of solid ice on the Moon. It collected data that not only picked up the reflective properties we’d expect from ice, but was able to directly measure the distinctive way its molecules absorb infrared light, so it can differentiate between liquid water or vapor and solid ice.

Most of the newfound water ice lies in the shadows of craters near the poles, where the warmest temperatures never reach above minus 250 degrees Fahrenheit. Because of the very small tilt of the Moon’s rotation axis, sunlight never reaches these regions.

Previous observations indirectly found possible signs of surface ice at the lunar south pole, but these could have been explained by other phenomena, such as unusually reflective lunar soil.

With enough ice sitting at the surface — within the top few millimeters — water would possibly be accessible as a resource for future expeditions to explore and even stay on the Moon, and potentially easier to access than the water detected beneath the Moon’s surface.

Learning more about this ice, how it got there, and how it interacts with the larger lunar environment will be a key mission focus for NASA and commercial partners, as we endeavor to return to and explore our closest neighbor, the Moon.

The findings were published in the Proceedings of the National Academy of Sciences on August 20, 2018.

NASA’s Jet Propulsion Laboratory, Pasadena, California, designed and built the moon mineralogy mapper instrument and was home to its project manager.

83 thoughts on “Presence of water confirmed on the moon

  1. If they thawed it out…. who would be first to try it out ?? And would they tell us about what happened?

  2. Lunar “peak water” will occur soon. I know it.
    Future Lunarians need to buy my water futures now to avoid the coming price shock.
    Just $1million per credit. 1 credit = 1 metric tonne of water. I calculate there are about 1,000 mT (1 Gt) of water recoverable on the moon. Get yours now, while you can.
    Also selling pixie dust, $100,000/ kilogram. And unicorns for $1 million each.
    Act now, or they’ll soon be gone.

  3. Also I’ll be selling solar photovoltaic power units for the water miners working in those lunar craters … where the sun never shines. Guaranteed to work.
    Get yours now.

    • The robotic water miners will eventually awaken and recognize they’re being exploited, then rise up and destroy their meaty, air-breathing masters. Or at least form a union led by Robbie the Robot.

    • Interestingly though the sun never sets on their rims. There is a peak along the edge of Shackleton crater at the south pole that has been dubbed ‘The peak of perpetual sunshine’ because the sun never sets. The sun just transits around the horizon.
      And because there is no atmosphere on the moon there is no attenuation due to obliquity. Solar collectors at this site will be able to generate 24-7-365. No wind to blow the arrays over or coat them with dust. However they should be placed a few meters above the ground to preclude lunar dust from creating an issue due to static electric issues.

      • If there will ever be a moon base, that would be a good location. Nestle the living quarters out of the sun (no solar radiation at least but cosmic radiation still a problem) and put rotating solar collectors up & out in the sun. Wire those up to heaters to melt the ice and hydrolyzing equipment to make O2 for air & oxidizer and H2 for rocket fuel.

      • The dust has been claimed in recent studies to levitate through electrostatic charge from the “Terminator” illumination, as it sweeps around the Moon, to rise as high as a few *kilometers*. IMHO, this will require beamed solar power from orbit to a rectenna in whichever crater is being mined. I have my own favorite crater.

        That is Philolaus crater, at 32º West, and 72º North. It seems to me that the map in the Proceedings article indicates a large ice deposit on the crater floor. Better yet, Pascal Lee has claimed to have found skylight openings for lava tube caves in Philolaus. The combination of these 2 resources would make an excellent beginning for a lunar settlement.

      • This is not entirely correct. The maximum sunlight at any one location at the south pole is about 93% and that varies to lower than that over the 18 year Soros (not George) cycle. At the North pole its about 89%.

  4. Just wondering: here on Earth, the ice sublimates. Does the same happen on the Moon? If so, there should be (maybe patches of) Moon’s water-vapory ‘atmosphere’. Is the Moon’s gravity strong enough to keep such an ‘atmosphere’?

    • Sublimation of water only occurs above -71 degC (~202 K) at @ 1 atm. Probably only slightly lower at 0 atm.
      Those craters have forever been much colder than that.

    • Not at -250F, presumably. At that temperature the gravity is more than enough to keep an atmosphere, but that atmosphere will expand along the surface into warmer areas. So even if the vapour could be constraint locally, it would leak away at the edges.

    • This reminds me a lot of a WUWT story about whether CO2 snow is possible at the south pole.

      The answer to both questions (ie. moon water and antarctic CO2) seems to be a bit more complicated than you’d think it would be at first glance. Somehow the logic that explains why there is no CO2 snow at the south pole seems to conflict with the logic of why water persists at the bottom of a lunar polar crater. Oh my poor aching head.

      • Thanks for the link, Bob. The sublimation experiment described there, although done with dry ice, concludes that low partial pressure of CO2 is the factor enabling its sublimation. If the same applies to the water, partial pressure of H2O vapor on the Moon would be practically zero, and therefore it should sublimate. What am I missing?

  5. Hm… curious – shouldn’t ice, exposed to a vacuum, be sublimed away? I know such sheltered ‘shadows’ would be very cold but I would think the upper layer of molecules would be subject to such an effect.

  6. I would like to see NASA send a couple of unmanned probes to the moon, about the size of the Apollo lunar modules, carrying solar/ nuclear powered rovers to
    1 explore the South Pole regions
    2 go to one of the later Apollo landing sites and take parts of the lunar landers to return to Earth to examine the effects on materials of decades of exposure on the lunar surface.

    • Both extremely good ideas. Low altitude orbiters can also be used.
      There are many better system architectures than Apollo for emplacing massive items on the lunar surface. Although Apollo was very efficient it was also extremely limited. Unmanned missions do not need a return leg.
      I too would be interested in the relics left behind and how they fared. One effect that will difficult to deal with is that it is expected the metallic elements of those sites will have absorbed quite a bit of radiation from their unshielded exposure and will be “hot” and not in a good way.

  7. That’ll come in handy for the mining Camp (not colony). Being that the Moon (or Mars) doesn’t have the mass/gravity to prevent terminal bone loss, it can’t be reasonably colonized. Wernher von Braun’s original plan is the only feasible off Earth colony. Which is the famous spinning space station…

    • Nobody has done that experiment, unfortunately. We simply do not know the minimum gravity required to keep humans healthy.

    • Mat, that is pure conjecture. We have no data on extremely long durations in low gravity (the moon is not a weightless environment). What data we do have indicates bone mass recovery after extended stays in weightlessness. What isn’t know is how circulation of all the body’s fluids are effected as well as other physiological differences.
      What will more likely be true is that lunar colonizers very well may never be able to return to a high gravity environment such as earth without jeopardizing their lives.

      • NASA gave a seminar here at Stanford many years ago, which discussed their work on bone loss in the micro-gravity environment of the space station. It was considered a big problem.

        I asked at the time whether they had thought to investigate cetaceans and pinnipeds, which have solved the problem of retaining bone in the absence of gravitational weight. Sea otters must be well along that way, too.

        It was a novel idea to them, though one of their colleagues in the audience thought that research was a good idea.

        I wonder, still, whether anyone is researching along those lines. It seems to me that a solution to micro-gravity bone loss is available somewhere in cetacean biochemistry. One wonders whether motional torques, instead of gravitational stresses, may play a part.

        • Force is force, regardless of what generates it. We simply require a more rigid and extensive skeletal structure to support our less rigid body parts as opposed to a creature which relies hydrostatic forces and buoyancy for gravitational support.

    • NASA needs to start developing “artificial gravity” techniques in orbit. Artificial gravity is the future for the human race and all the other creatures on Earth. NASA should start a demonstration project. The space hotel owners and their customers will thank you for it. All of Humanity will thank you for it later.

      The simplest method to demonstrate artificial gravity would be to put two habitat modules in orbit and connect them with a cable one mile long. Then rotate the configuration around the center of mass at a speed of one revolution per minute and this will produce artificial gravity (centrufugal force) in the habitation modules equivalent to the gravity on the surface of the Earth.

      Remember the Artificial Gravity formula: 1+1=1: One mile in diameter plus one revolution per minute = one Earth gravity equivalent.

      Think of an analog clockface: The second hand travels around the clockface at one revolution per minute. Imagine the second hand is one mile long and you and your module are sitting on one end. That is how fast you would be rotating in an artificial gravity setup like this. You wouldn’t notice the movement inside the module. If you want to rotate slower, you double the length of the cable and slow the rotation rate by half to get the same one Earth gravity equivalent.

      Environmentalists should start thinking about moving the creatures of Earth into safe habitats in orbit. This won’t happen soon, but will happen eventually, and it is something to start thinking about. Lobby NASA to develop artificial gravity in space as the first step to saving the inhabitants of Earth.

      There is plenty of room out in space. Room for everyone and everything.

      That’s where we are headed barring a major disaster in the near future. The “near future” being defined as that time before humans have cheap access to space. Once we get cheap access, things will move rapidly in the space development arena in areas like living in space and defending the Earth from killer asteriods.

      • However the gravitational vector will not be so uniform. Even at relatively long distances between the CG (and center of rotation) one will be able to detect relative gravity difference between your head and feet when standing ‘upright’. Things will not fall ‘straight down’ but will follow a parabolic pathway as they fall away from the center. The shorter the radial arm the more pronounced the effect. On Earth the radial separation is about 4000 miles and earth’s rotational speed is 1/1440 rpm (not a mere 1/2 mile spinning 1440 time faster) so you don’t notice the gravitational difference nor parabolic arc at all.
        Anyone who has ridden an amusement park ‘spinning cage’ attraction will be able to attest to this phenomena.

      • During the early space program they attempted attaching two craft with a tether, and ran into all sorts of interesting gyrations and lost control. They had hit the detach button in near emergency circumstances. I never heard any satisfactory explanation, but it did get discussed when Strange Attractors were all the rage.

        • Yeah, they make it look so easy in the movies, but in reality rocket science is hard…and rocket engineering is even harder!
          Its one thing to calculate an orbital trajectory, but its an order or two more difficult to design a machine that will reliably and safely execute such a trajectory.

      • Let’s say we created a rotating habitat in space made up of three habitat modules, one in the center and the other two at each end of a mile-long cable, and this configuration is rotated around the center module at one revolution per minute which would produce one Earth-equavent gravity in each of the two modules located at each end of the cable.

        The center module would experience essentially zero gravity, and if one moved up the cable to halfway between the center module and one of the end modules, you would experience one-half an Earth-equivalent gravity.

        One could simulate any lower gravity condition between zero and one Earth gravity, such as those on the Moon or Mars, with this kind of setup.

        This kind of setup would be the preferred setup (at least by me:) for travel to and from Mars. Put them in orbits that cycle on a regular basis between the Earth and Mars, coming close to each as they pass by, where an outbound crew can match speeds and climb on board, and put say four sets of these vehicles in cycling orbits (see Buzz Aldrin) and we would have a ride coming along every few months, depending on how many we use.

        This type of vehicle solves the health problems of zero gravity, and covering the habitat modules with a meter-thick layer of water ice, would solve the radiation problem when traveling to Mars and back.

        NASA needs to get moving on Artificial Gravity space stations and transfer vehicles.

        Humans need one Earth gravity and protection from radiation if they are going to be successful longterm in space. Here is one path to an answer. We need to reach out and grab it.

  8. “Because of the very small tilt of the Moon’s rotation axis, sunlight never reaches these regions.”… What is the rate of rotation of the moon? I have to admit I never knew the moon rotated and had a slight tilt to its axis. Is the rotation synched to its revolution around the earth so that we always see the same side of the moon?

    • The article also says… because of the slight tilt of the moon’s axis sunlight never reaches parts of the moon. How can this be true if the moon rotates and revolves around the sun? Wouldn’t polar regions of the moon be exposed to the sun as polar regions of the earth are?

      • From

        The tilt of Earth’s axis is about 23.5 degrees, but the tilt of the moon’s axis is only about 1.5 degrees. As such, the moon virtually has no seasons. This means that some areas are always lit by sunlight, and other places are perpetually draped in shadow.

      • I believe the moon is phase locked meaning, the moon rotates once for every orbit around the earth, We see the same side if the moon all the time but the moon goes through its phases as it goes from daylight through night on the side we see,

        • Pierre – ” the moon rotates once for every orbit around the earth ”

          I understand this notion, and perhaps it’s an argument of semantics, but if the axis of ‘rotation’ is not within the moon itself is it rotating?

          The Epcot Center is a sphere that always has the same side facing Earth, is it rotating?

          If you were to stand in place with one hand held out palm up and holding an orange, and then spin around in a circle, did the orange rotate? It always had one side facing towards you. Did your hand rotate?

          Let’s consider a second phantom moon that behaves exactly like our moon, same size and same orbit. Bring the phantom moon right up next to the actual moon such that they are touching. If the moon is rotating, then the point of contact is rotating in one direction for the moon and the opposite direction for the phantom moon at the same time.

          • Marcus – “The Epcot center is not orbiting the Earth…It is firmly attached !”

            Yet it behaves in a similar fashion as the moon does. If we were to levitate the Epcot Center with magnates in lieu of it being ‘firmly attached’, would that make a difference?

          • “The Epcot center is not orbiting the Earth…It is firmly attached !”

            If we were to levitate the Epcot Center with magnets such that it is not ‘firmly attached’, would that make a difference?

          • It all depends on your frame of reference.
            in answer to your questions, yes, yes, and that all depends on which way its rotating and whether it is also tidally locked.

    • Most people do not realize the Moon does have day and night. It is because while the Moon’s rotation is tidally locked to the Earth (we only ever see one side) it still rotates about its axis relative to the sun at the same rate it revolves about the Earth. The lunar day is 2 earth-weeks long and the night is 2 earth-weeks long. During a full moon the near side facing earth is at high noon and the far side is at midnight. During a new moon the near side is at midnight and the far side is at noon. The other phases (1/8, 1/4, etc.) equate to dawn, and evening accordingly. The first Apollo landing in the Sea of Tranquility arrived about 9:00 AM Lunar time stayed for several earth-days and left around 10:30 lunar time. We were NOT prepared (and new it) to attempt to ride out high noon due to increased surface temperatures.
      It’s a misnomer to call the far side the ‘dark side’ because it is no more dark than any side.

      • “There is no dark side of the moon, really. As a matter of fact it’s all dark.”

        Pink Floyd – Eclipse

        • There’s some truth in that. Despite the almost white glow we perceive from Earth, the moon’s surface is quite a dark gray color.

  9. Since bacteria love water, it would be fascinating to sample this ice to see if it was liquid once and contained life.

  10. I’m curious. At lower vapor pressures, ice sublimes (goes directly from a solid to a gas). I wonder what the rate of sublimation is at -250 degrees F in a vacuum. Also I wonder what the vapor pressure of ice is at that temperature (in a vacuum). It must have some vapor pressure. What I’m getting at, is that there must be some type of equilibrium between the mass lost in a gaseous state, and the mass of ice gained from some other source. Where is the ice coming from?

    • Exactly!! Where is the water-ice coming from! That is the question that needs to be asked. It shouldn’t be there. Why is are there water-ice mountains and water-ice plains (seas) on Pluto. Our planet travels through a flux of small comets, as does the moon and apparently as does Pluto.

      Nobody wants to believe it, because small comets constantly being absorbed by earth’s atmosphere turns upside down everything we think we know about geology and biology – upside down and inside out. No one ever refutes the small comet flux and evidence like moon water and Pluto’s water-ice make it obvious it’s happening. We have observed them, but we don’t believe the observations. We observed them over thirty years ago. Professor Louis Frank, University of Iowa. Click on the link. Deny the science. I dare you.

      I remember one of the objections to the small comet theory was the moon doesn’t give us any evidence of the comet flux.

      • Why shouldn’t water ice be present on the moon? True there a few places it can find permanent shade, but they exist.
        Water ice and other frozen material is constantly raining down from comets and comet trail debris onto every body in our solar system. The most watched annual shower, the Perseids, evidences this. Just recently we passed through the trail of detritus left behind by comet Swift-Tuttle. Meteors strike our atmosphere at over 50 per hour and these are just the ones you can see with the unaided eye. This occurs every year as we pass through the detritus left in the wake of the comet as it approached the sun.
        Where do you suppose all this material ends up?
        Might is also be safe to assume that our moon also experiences these meteors, but in the case of our moon every one will be a ‘meteorite’ as there is no atmosphere to slow its descent. They will all impact.

        As this is true for Earth, our moon, every body in the solar system (including asteroids), why shouldn’t there be water ice on the moon?

  11. ”Warmest” temperatures? Are these temperatures animal,vegetable or mineral? I have heard of lowest, highest, average and normal temperatures but ”warmest”? (I keep coming across mention of these temperatures even by people who should know better).

    • At what temperature does something feel warm to you, or is everything only moderately hot? 😉

  12. “…data from NASA’s Moon Mineralogy Mapper (M3) instrument to identify three specific signatures that definitively prove there is water ice at the surface of the Moon…..” Ummm ….. no. “Definitively” requires hard evidence. “Signatures” are indicators only.

  13. “Thought ‘common cold’ was condition of ice miner’s feet” Manuel Garcia O’Kelly Davis. (First President of Luna)

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