Ice Confirmed at the Moon's Poles
A team of scientists used NASA's Moon Mineralogy Mapper instrument data to identify three signatures that definitively prove there is water ice at the surface of the Moon.
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.