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.
Because of the very small tilt of the Moon’s rotation axis, sunlight never reaches these regions.
Credits: NASA/Elphic

 

The Moon research community is beaming about the new evidence of exposed water ice in the lunar polar regions.

NASA’s Moon Mineralogy Mapper, or M3, instrument flew aboard Chandrayaan-1, India’s first mission to the moon, and provided the first mineralogical map of the lunar surface.
Credit: NASA/JPL

Using data from the NASA’s Moon Mineralogy Mapper (M3) spectrometer experiment, a team of researchers — led by Shuai Li of the Hawaii Institute of Geophysics and Planetology in Honolulu, Hawaii — searched for and found direct evidence for the presence of water in the permanently shadowed areas in polar craters on the Moon.

M3 flew as part of the scientific payload onboard the Indian Space Research Organization’s Chandrayaan-1 spacecraft that circuited the moon in 2008-2009.

Previous data could not specifically verify the existence of water ice, but Li et al. provide “robust evidence” for its presence on the Moon’s surface.

Lines of evidence

“This is a critical paper as it demonstrates that we have four independent lines of evidence that there are surface ice exposures at the lunar poles,” explains Clive Neal, a leading lunar expert at the University of Notre Dame.

“With the neutron data, we also know that these deposits extend into the subsurface. Therefore, we now have great maps that we can use to target prospecting surface rovers,” Neal told Inside Outer Space.

What’s not known

Neal said as far as on-the-spot use of the water ice reserves, what still needs to known is the size of the deposits, the geomechanical properties of the regolith it is in, ease of extraction, bulk composition (impurities and the refining process necessary to produce clean water of life support and rocket fuel, etc.).

Bottom line for Neal: “It is time to get to the surface of the Moon and start prospecting!”

Artist’s rendering of the LCROSS spacecraft and Centaur separation.
Credit: NASA

North and south poles

Angel Abbud-Madrid, Director of the Center for Space Resources at the Colorado School of Mines in Golden, Colorado, also finds the new research exciting.

“This new piece of evidence is valuable in that it provides additional confirmation on not just the presence of ice on permanently shadowed regions — which was obtained from previous instruments and from NASA’s Lunar CRater Observation and Sensing Satellite (LCROSS) impact mission in 2009 on Cabeus crater — but of water ice exposed on the surface in various well-defined spots on both the North and South poles,” Abbud-Madrid tells Inside Outer Space.

Water extraction

“These data are of importance for prospecting and in-situ resource utilization operations related to water extraction from the lunar poles,”Abbud-Madrid adds. The locations of surface-exposed water ice described in the new study, he said, could be used to select potential sites for more extensive ground truth exploration to qualify and quantify the ice content on these regions.

“This information is crucial to select the most appropriate extraction method to be used for ice exposed on the surface, as opposed to techniques to drill and recover subsurface ice,” Abbud-Madrid concludes.

Credit: LIQUIFER Systems Group 2018/René Waclavicek (used with permission)

Lunar bases

The new research provides “robust evidence” for the presence of water ice on the Moon’s surface, notes James Head at the Department of Earth, Environmental and Planetary Sciences at Brown University in Providence, Rhode Island.

“If ice is at the surface, this means that much more could be buried at depth and covered and preserved below insulating soil, or diffused into and frozen in the soil layers,” Head advises. “This is very exciting news, and provides significant impetus for future international landings in the polar regions to drill and return samples of this ice. Ice deposits in significant quantities on the Moon could provide resources for future lunar bases and for fuel for future human exploration of deep space,” he states.

To read the original research paper in the Proceedings of the National Academy of Sciences, “Direct evidence of surface exposed water ice in the lunar polar regions” by Shuai Li, Paul G. Lucey, Ralph E. Milliken, Paul O. Hayne, Elizabeth Fisher, Jean-Pierre Williams, Dana M. Hurley, and Richard C. Elphic, go to:

www.pnas.org/cgi/doi/10.1073/pnas.1802345115

 

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