Ice Confirmed at the Moon’s Poles

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. (Credits: NASA)

MOFFETT FIELD, Calif. (NASA PR) — 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 -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.

Author: Frank Tavares

  • gunsandrockets

    What wonderful news. That surface ice is also much more widely distributed than I ever imagined.

  • Tom Billings

    The link, from clicking on the map of the Moon’s poles, gives a “not found” message.

  • Tom Billings

    I *hope* I am not misreading the more detailed map I found in the Proceedings article, but it *seems* there is a large ice deposit indicated for Philolaus crater, at 32º west and 72º North. That would be a happy occasion for our team, because Pascal Lee believes he has found indications of lava tube caves in Philolaus crater. These 2 resources together would make a happy combination for a lunar settlement!

  • Andrew Tubbiolo

    You know what this means? 7-11’s with ISRU Slurpee’s!

  • Paul_Scutts

    Appears to be a lot more surface water remaining at the South Pole compared to the North Pole.

  • windbourne

    If that is true, we really need to get to the moon first and grab that spot NOW.

  • The issue now is, where is the best location where lunar surface ice is closest to one of the Peaks of Persistent Illumination (PPIs)? From my eyeballing of these new graphs, it appears that the best location is at the 8 o’clock position on Shackleton’s rim where there is close proximity of one of these PPIs to a crater just off the rim.

    Telerobots can push large amounts of regolith on top of a flat-roofed, inflatable habitat. So the key site selection criteria shouldn’t be a place of natural shielding (e.g. lava tube) but where near-permanent sunlight is. Without a lot of sunlight, you have the problem of surviving the long lunar night and you slow the electrolysis of water to propellant.