Chandrayaan-2 Radar Data Reveals Strong Evidence of Buried Ice Near Moon’s South Pole

India’s Chandrayaan-2 mission has delivered another major scientific result years after reaching lunar orbit, with researchers finding strong radar evidence of subsurface water ice inside ultra-cold craters near the Moon’s south pole. The finding comes from a new study by scientists from the Physical Research Laboratory in Ahmedabad, published in npj Space Exploration on 6 May 2026.

The study focused on a special class of lunar craters known as doubly shadowed craters. These are craters located inside larger permanently shadowed regions, where sunlight does not directly reach and even scattered light or heat from nearby illuminated surfaces is blocked by raised rims. According to the paper, such crater interiors can reach temperatures of around 25 Kelvin, or nearly minus 248°C, making them among the most stable natural cold traps in the solar system.

Using Chandrayaan-2’s Dual Frequency Synthetic Aperture Radar, scientists examined nine doubly shadowed craters located within the larger Faustini, Haworth and Shoemaker craters near the lunar south pole. The radar instrument used full-polarimetric observations in L-band and S-band, allowing researchers to look for subsurface signatures that may indicate ice mixed within lunar soil.

The most important result was that four of the nine craters showed radar behaviour consistent with buried ice. These regions displayed circular polarization ratio values greater than 1 along with a low degree of polarization below 0.13. In simple terms, the radar waves appeared to be scattering in a way that is more consistent with ice-rich material below the surface than with ordinary rough rock alone.

This distinction matters because radar signals from rough rocky terrain can sometimes mimic signs of ice. The researchers therefore combined two diagnostic indicators — circular polarization ratio and degree of polarization — to reduce ambiguity. Their method strengthens the case that the detected signals are linked to volumetric scattering from subsurface ice, rather than only surface roughness.

One crater inside Faustini drew particular attention. The study describes a roughly 1.1-km-wide crater with enhanced radar polarization and a prominent lobate-rim morphology, which may indicate that an impact excavated into a buried ice-rich layer. This suggests that some lunar impacts may naturally expose or reveal ice-bearing material that has remained protected beneath the surface.

The discovery adds to a long chain of lunar water findings in which Indian missions have played a major role. NASA notes that data from the Moon Mineralogy Mapper aboard Chandrayaan-1 contributed to the first high-resolution mapping of confirmed water ice in permanently shadowed lunar regions, while later missions continued to show that water exists both in shadowed and sunlit parts of the Moon.

What makes the latest Chandrayaan-2 result important is that it narrows the search from broad evidence of lunar water to more specific locations where ice may exist beneath the surface. This is crucial for future lunar exploration because buried ice could become a resource for drinking water, oxygen production and hydrogen-based fuel if future missions can access it safely and economically.

The researchers also caution that the distribution of ice is likely uneven. Not every crater studied showed the required radar signatures, meaning subsurface ice at the lunar south pole may be patchy rather than uniformly spread. That finding is useful in itself because future missions will need precise landing-site and drilling-site selection rather than broad assumptions about water being present everywhere in shadowed regions.

For India, the result strengthens Chandrayaan-2’s scientific legacy. Though the mission’s lander did not achieve a soft landing in 2019, ISRO says the orbiter has remained healthy with operational payloads, continuing to generate valuable scientific data on the Moon’s surface, composition and exosphere.

The latest finding also explains why the lunar south pole has become the centre of global exploration interest. If stable subsurface ice exists inside ultra-cold crater traps, then future lunar bases may not need to carry every kilogram of water from Earth. Chandrayaan-2’s radar data therefore does more than confirm another scientific clue; it helps map the resource geography of the Moon’s next human frontier.