Lunar Ice Theory Challenged

A new study challenges previous assumptions about the abundance of lunar ice in the Moon’s shadowed regions, leaving the community of lunar exploration with more questions than answers.

Scientists previously speculated that the permanently shadowed craters of the Moon contained water ice. It seemed logical that the sunless regions were perfect natural freezers for trapping ice and offered a potential lifeline for astronauts on the Moon.

A new study published in Science Advances challenges the idea of abundant lunar ice on the surface of the Moon.

The Search for Lunar Ice

The lack of atmosphere on the Moon means the deep craters near the poles are permanently shadowed and remain incredibly cold. Scientists speculated these areas contained vast amounts of lunar ice that would be a potential resource for astronauts, offering drinking water, oxygen, and rocket fuel.

Astronomers use the unique reflective properties of water ice to detect its presence, as it reflects visible light differently than lunar regolith and scatters light in a distinctive pattern. If there were large quantities of ice on the Moon, the differences would be easily detected through high-resolution imagery.

ShadowCam Observations

Shuai Li and a team of astronomers from the University of Hawaii at Manoa used ShadowCam, a camera onboard the Korea Pathfinder Lunar Orbiter, to observe these shadowed regions.

ShadowCam is designed to capture high-resolution visible-wavelength images to help scientists measure the reflective and scattered patterns of the lunar surface with precision.

Astronomers suspected the lunar ice formed with regolith, but hoped 20-30 percent of the ice would be detectable using the ShadowCam technology. The mixtures would give off unique optical signatures that would contain more reflective and forward-scattering properties compared to the surrounding rock.

The observations do not completely rule out the presence of ice, but suggest possible trace amounts that cannot be detected within the limits of current technology. The team did detect signatures that may be consistent with mixtures of less than 10 percent water ice.

Next Steps in Lunar Ice Exploration

Li and his team are working to push detection limits further with a goal to detect concentrations as low as one percent. Even small amounts of ice would offer valuable insights into the history of the Moon and offer crucial resources for human exploration.

Sources:

The Daily Galaxy: Lunar Ice Discovery Takes a Hit: No Clear Evidence of Large Deposits Found
Phys.org: ShadowCam search casts doubt on abundant lunar ice
Scientific American: There might be less water on the moon than we’d hoped

Featured Image Courtesy of NASA Goddard Space Flight Center’s Flickr Page – Creative Commons License