Innovative methods refine search for lunar ice

Innovative methods refine search for lunar ice
by Clarence Oxford
Los Angeles CA (SPX) Apr 24, 2025

Scientists continue to push the boundaries of lunar exploration with new strategies to identify and map ice deposits on the Moon. Ice could play a vital role in supporting future human activity on the lunar surface, providing life support resources and fuel ingredients. At the University of Hawai'i at Manoa, researchers are leading two pioneering investigations to enhance our understanding of where and how much ice is hidden on the Moon.

Surface scouting with ShadowCam

Shuai Li, an assistant researcher at the Hawai'i Institute of Geophysics and Planetology (HIGP) in the UH Manoa School of Ocean and Earth Science and Technology (SOEST), had previously confirmed the presence of ice within permanently shadowed polar regions. Now, under his guidance, graduate student Jordan Ando has employed data from a highly sensitive instrument known as ShadowCam aboard the Korea Lunar Pathfinder Orbiter.

These polar craters, permanently deprived of direct sunlight, are dimly lit only by light reflected from crater walls. ShadowCam is engineered to detect this faint illumination, enabling scientists to peer into these obscured areas.

"Ice is generally brighter, that is, reflects more light, than rocks," said Ando. "We analyzed high-quality images from this sensitive camera to look really closely into these permanently shaded areas and investigate whether water ice in these regions leads to widespread brightening of the surface."

While the imagery revealed no significant surface brightening due to ice, it allowed the team to refine previous estimates of surface ice content. Earlier studies had suggested that water ice might constitute between five and 30 percent of surface material. The new analysis narrows this range, indicating that water ice likely accounts for less than 20 percent.

Probing for ice beneath the surface

In a separate project, scientists from HIGP and the Department of Physics and Astronomy have unveiled a novel technique to detect subsurface ice, published in *Geophysical Research Letters*.

"With our recent study, we showed that a new technique for detecting buried water ice on the Moon is possible using naturally-occurring cosmic rays," said Emily S. Costello, the study's lead author and a postdoctoral researcher at HIGP. "These ultra-high-energy cosmic rays strike the lunar surface and penetrate to the layers below. The rays emit radar waves that bounce off buried ice and rock layers, which we can use to infer what's below the surface."

Using sophisticated simulations, the team modeled how these radar waves would travel through lunar regolith and interact with different materials.

"This method for searching for water ice on the Moon is brand new and really exciting," noted Christian Tai Udovicic, a study co-author who presented the findings at the Lunar and Planetary Science Conference in Houston, Texas. "Since it relies on high-energy physics that only a few scientists in the world are experts in, even planetary scientists who are studying ways to find lunar water ice are often surprised when they hear about this technique."

The research group is currently developing a radar instrument customized to capture these subtle signals. They aim to conduct a full system test by early 2026 and seek opportunities to deploy it to the Moon, where it could help identify large underground ice reservoirs for the first time.

"More and more, Hawai'i is becoming a hub for space exploration, and specifically the exploration of the Moon," said Costello. "These projects, led by UH Manoa scientists, represent up-and-coming opportunities for students and professionals in Hawai'i to lead and participate in the budding space industry."

Research Report:Cosmic Rays and the Askaryan Effect Reveal Subsurface Structure and Buried Ice on the Moon