40,000 Square Kilometers of the Lunar Surface Can Hold Water

A new study finds 40,000 square kilometers of the lunar surface has the capacity to hold water, which is about double previous estimates.

0.15% of the lunar surface is permanently shadowed, with ~10% of this area distributed in patches smaller than 100 m, that is at scales smaller than previously mapped by LOLA topography-based illumination models. The most numerous cold traps on the Moon are ~1 cm in scale.

The abundance of small-scale cold traps implies that future missions exploring for ice may more easily target and access one of these potential reservoirs. Given the high loss rates due to micrometeorite impact gardening and ultraviolet photodestruction37, the detection of water within the micro cold traps would imply recent accumulation. Therefore, the presence or absence of water in micro cold traps could serve as an indicator of volatile sources in the inner Solar System. If water is found in micro cold traps, the sheer number and topographic accessibility of these locales would facilitate future human and robotic exploration of the Moon.

Nature Astronomy – Micro Cold Traps on the Moon

Water ice is thought to be trapped in large permanently shadowed regions in the Moon’s polar regions, due to their extremely low temperatures. Here, we show that many unmapped cold traps exist on small spatial scales, substantially augmenting the areas where ice may accumulate. Using theoretical models and data from the Lunar Reconnaissance Orbiter, we estimate the contribution of shadows on scales from 1 km to 1 cm, the smallest distance over which we find cold-trapping to be effective for water ice. Approximately 10–20% of the permanent cold-trap area for water is found to be contained in these micro cold traps, which are the most numerous cold traps on the Moon. Consideration of all spatial scales therefore substantially increases the number of cold traps over previous estimates, for a total area of ~40,000 km2, about 60% of which is in the south. A majority of cold traps for water ice is found at latitudes over 80° because permanent shadows equatorward of 80° are typically too warm to support ice accumulation. Our results suggest that water trapped at the lunar poles may be more widely distributed and accessible as a resource for future missions than previously thought.

SOURCES- Nature Astronomy
Written By Brian Wang, Nextbigfuture.com

26 thoughts on “40,000 Square Kilometers of the Lunar Surface Can Hold Water”

  1. So the earth should be bone dry too but it ain't. If the earth has water then the moon must have water. But the proof of the pudding is in the eating so drill and find out.

  2. Hence the vague reference to a metallurgical miracle. If you had a supermaterial you could run your reactor at 5000 C (the high pressure liquid uranium inside your supermaterial tubes) and so get good ISP from Oxygen.

    Only problem is we have no such material.

  3. Oxygen? Not Hydrogen? There are groups that say that a suitable nuke engine can dissociate H2 and get some 1100 s, but oxygen would be too heavy to give a good specific impulse.

  4. Because the lunar surface was heated to red hot temperatures during its formation, vaporized its water and had no ability to retain it in the presence of solar wind and slight gravity.

    The moon is short of all sorts of light/volatile elements… for a reason.

  5. Meh just come up with a metallurgy miracle and transition to Nuclear powered monopropellant engines using LOX as the propellant.

    I did say a metallurgical miracle for a reason…

  6. If you must import something from Earth bring kerosene. Liquid at a good range of temperatures and full of nothing but Carbon and Hydrogen- elements the moon lacks.

    Alternately send shipments of Ammonia ice to the moon from Mars. Lots of Nitrogen and Hydrogen, again elements the moon lacks and you can move bulk Ammonia ice up from Mars to the Moon with less energy than from the bottom of Earth's gravity well.

  7. It may well be true that we don't need the moon to launch to Mars.

    But Mars is hardly the only place in the solar system. Even bases on the moon would want fuel. Not to mention orbital locations.

  8. With nights lasting nearly 14 days on the Moon, water vapor resulting from meteor and micrometeorite impacts could be under cryo darkness for nearly 14 days before they reached dark safe havens such as permanently shadowed craters at the lunar poles and the dark interiors of lava tubes.

    Surface temperatures in regions experiencing nighttime conditions on the Moon can drop to minus 280 degree F (minus 173 C). Water, of course, freezes at just 32 degrees F.

  9. Is it even worth the time and effort extracting lunar ice to make water? Starship can carry plenty of water that can be reused for personnel on a moon base. Elon Musk has already said we don't need the moon to launch to Mars so making rocket fuel from the lunar water is a kind of a waste of time.

  10. Water has a vapour pressure which is temperature-dependent. In these cold traps which are about 50 or so K, the pressure is low enough that it approaches vacuum pressures, and thus the ice does not sublimate even over geological time scales.

    There was even an article a few weeks ago about someone proposing using sieves to separate out ice and metal grains through difference in specific weight, because otherwise the ice granules behave just like any other type of rock.

  11. Wouldn't it have to be in liquid form to evaporate? If its frozen it could sublimate, but I'm guessing that would happen if its exposed to vacuum. From what I've read elsewhere, the water appears to be underneath the surface of the regolith. There's also some articles that talk about it being in the form of hydroxyls or contained in volcanic beads.


  12. It is incredible. How can any ice not just evaporate? Is it the lack of atmosphere that means there is nothing for the water to ride on? Practically, I would have thought the lack of atmosphere would have meant the water/ice just sublimated that much quicker

  13. There's no doubt in my mind that the permanently shadowed depths of hundreds of lava caves on the lunar surface are probably rich in water ice and carbonaceous materials from both ancient volcanic activity and from gaseous distribution from meteorite and micrometeorite impacts over the past billion years.

  14. I've read somewhere that the amount of water (hydroxyl groups mostly) in the lunar soil they are talking about, is like a 1/10th of the water in "dry" Martian soil.

    And there is discussion if it's even viable to extract it.

    Therefore I don't have high hopes of this being useful for anything beyond a curiosity.

    The ice on the polar craters is much more concentrated and potentially useful, though.

  15. Why shouldn't water exist deep under the lunar surface? I can understand the lack of water near the surface but I can't understand why people would think water would be missing deep down. I think we should drill and find out.


Leave a Comment