There has long been talk of ice at the Moon’s south pole.
But no one knows where it is, how much there is, or how many meters below the surface it lies.
You might think the answer is simply to drill for it, but there is a reason that is not feasible.
Three-line summary
1. Lunar exploration is now looking for ice by knocking rather than drilling.
2. Ice-mixed soil transmits seismic waves two to three times faster.
3. Confirmation begins with Chang’e 7 in August.
Why Find Water First?
For people to stay on the Moon for long periods, there needs to be water. It is not only for drinking.
Running electricity through water splits it into hydrogen and oxygen. Oxygen is used for breathing, and hydrogen becomes rocket fuel. In other words, if water can be obtained on the Moon, the Moon becomes a gas station. Transporting water from Earth requires fuel to push that weight upward, and then more fuel to carry that fuel. A spacecraft headed to Mars has an entirely different design depending on whether it leaves Earth fully fueled or stops at the Moon to refuel before departing.
A Floor Never Touched by Light
The Moon’s rotational axis is almost upright. Because it is not tilted like Earth’s, the floors of deep craters near the south pole have never received sunlight. These places are called permanently shadowed regions.
They are among the coldest places in the solar system. When water molecules brought by comets or the solar wind reach those floors, they cannot evaporate again and remain trapped there for billions of years. The reason ice remains and the reason exploration is difficult are the same.
In 2009, NASA deliberately crashed a 2.3-ton spacecraft and a rocket upper stage into a south polar crater, confirming water in the dust thrown upward. Even 17 years later, its distribution has still not been mapped.
Drilling Gives You a Point; Knocking Gives You an Area
The limitation of drilling is clear. It tells you only about the one spot drilled. A single lander can drill only a few holes at most, while the south polar region that must be examined is a broad area where multiple craters overlap. To decide where to drill, a map is already needed—but to make a map, drilling is needed.
A study published in the international journal *Science Advances* on July 31 presented a way to break this cycle. It comes from researchers at the University of Maryland, Lawrence Berkeley National Laboratory, and the University of Hawaiʻi.
The key is this: ice-mixed soil and dry soil transmit vibrations in completely different ways.
Ice hardens the spaces between grains like cement. The more solid a material is, the faster vibrations travel through it. The researchers’ measurements found that seismic waves passed through ice-mixed lunar regolith two to three times faster than through dry regolith. In addition, the vibrations do not simply pass through; a substantial portion is reflected back. It is like sound hitting a wall and returning as an echo.
If the speeds differ and echoes return, measuring vibrations at the surface alone can reveal what lies beneath. The researchers calculate that this method could map structures to about 800 meters underground.
It is not unfamiliar technology on Earth. It has been used for decades to search for oil and gas, and the principle is the same.
The Experiment Was Conducted in Arizona
Since it cannot be tested on the Moon, the researchers made volcanic rock brought from Arizona resemble lunar dust, froze it in a laboratory, and measured vibration speeds. They then applied a model of temperature distribution at the lunar south pole and ran computer simulations of how moonquakes would spread when they encountered underground ice layers.
The Moon has quakes. Seismometers left behind by Apollo astronauts actually recorded them. Tidal forces, temperature changes, and meteorite impacts cause them. Because naturally occurring vibrations can be used, there is no need to set off explosives.
Field Measurements Begin in August
China’s Chang’e 7 is targeting a launch in the second half of August 2026. Along with an orbiter, lander, and rover, a small hopping probe will travel with it. The plan is for this hopping probe to jump into a permanently shadowed region and directly measure water molecules. Its instruments also include a seismometer.
The target landing site is near Shackleton Crater.
Our Satellite Was the First to Image Inside That Crater
If the name Shackleton sounds familiar, there is a reason. The interior of that very crater was photographed and released in early 2023 by Danuri, Korea’s lunar orbiter, using the ShadowCam camera carried jointly with NASA.
How did it photograph a place with no light? Rather than creating light, it used a method that gathers the extremely faint light reflected from surrounding terrain or Earth. That is why it was made 200 times more sensitive than a conventional camera. It was the first time the terrain of a floor that had never received sunlight appeared in photographs.
Still, photographs can reveal only the surface. They can show what covers the floor, but they cannot capture how many meters below it ice may lie. That is precisely the gap this seismic-wave study aims to fill, and why the two methods overlap. The sequence is to narrow candidate sites with photographs and read beneath them with vibrations.
A lander from another country is now heading to a site where our satellite first lifted the lid.
What Has Not Yet Been Confirmed
What this study demonstrated is that the method works, not how much ice exists at the lunar south pole. Whether frozen rocks in a laboratory and actual lunar regolith will be the same also remains within the model for now.
So after August, there is one thing to watch: whether Chang’e 7’s seismometer actually sends back records, and whether those records match the speed differences predicted in the laboratory.
Photos of permanently shadowed regions taken by ShadowCam are available at original resolution in the official ShadowCam image gallery. To see what a floor that has never received light looks like, viewing one image is faster than reading about it.
In lunar exploration news, it is easy to focus only on whether a landing succeeds, but what changed this time is what can be done after landing. The idea of reading the interior by knocking will ultimately determine where to drill.
Sources
- Phys.org Moonquakes could reveal ice buried beneath lunar south polar craters
- Highways.Today Hunting for Lunar Ice is Sharpening the Tools That Map Earth's Subsurface
- NewsSpace China Begins Five Major Missions in Earnest to Become a Space Power in 2026
- TechM Sci-Tech: Is There Really Water on the Moon?
- NASA ShadowCam Images Lunar South Pole Region — ultra-low-light camera aboard Danuri
The original study was published in the July 31, 2026 issue of the journal *Science Advances*.