Chandrayaan-2 data reveals water buried on Moon for billions of years is stable: International study

NEW DELHI: A new international study involving researchers from Physical Research Laboratory (PRL), IISER and Institute of Remote Sensing, has revealed that water ice deposits in the Moon’s permanently shadowed regions are far more stable than earlier believed.

“Moon’s permanently shadowed regions (PSRs) are capable of preserving water-ice and other frozen volatiles for billions of years if temperatures remain sufficiently low. Water ice is preserved on the PSRs of Moon’s South Pole, which have witnessed multiple impacts. (However,) 74% of PSRs are unaffected by impacts,” said the study titled “Impacts into the lunar permanently shadowed regions”, which was published in “Nature” on April 2.

The findings have come at a time when countries are racing to launch manned missions, like the ongoing Artemis II mission and India’s crewed lunar landing mission by 2040, to the Moon with an aim to set up lunar bases in future.

Using high-resolution orbital imagery and impact modelling, the research team mapped millions of tiny craters, ranging from one to 20 metres in size, across PSRs between 85° and 90° south latitude. The study also took help from data generated by Nasa’s camera and Isro Chandrayaan-2 orbiter. “In this study, 5 m-7 km diameter craters were mapped within the subset of PSRs greater than 1 km2 in area located between 85°–90°S latitude using ShadowCam, 1–20 m craters were mapped within the Connecting Ridge region near lunar south pole using both ShadowCam (Nasa) and Chandrayaan-2 Orbiter High-Resolution Camera (India) and an estimated count was produced,” the study said.

“Despite millions of impacts into the PSR and release of volatiles from the crater cavity, the lunar south pole region still has the potential to preserve shallow ice, making it a promising target for future India’s Chandrayaan-5 / LUPEX mission,” the study further said.

The study suggests that small craters in these dark regions may have disturbed the ice buried below the surface. It also says that in areas without craters, natural surface churning (called “gardening”) can mix the ice vertically, bringing it closer to the top. This makes such places good targets for future missions to explore and use lunar ice.

Chandrayaan missions were the first to confirm the presence of water on the Moon. While Chandrayaan-1 (2008) first detected lunar water, Chandrayaan-2 confirmed its stability in polar regions and Chandrayaan-3 found further evidence of hidden, buried ice, marking a crucial step for future exploration. Chandrayaan-5, also known as the Lunar Polar Exploration (LUPEX) mission, is a joint project between Isro and Japan's JAXA, scheduled for launch around 2027-28. It aims to land at the South Pole to locate and analyse water ice, employing a heavy Japanese rover and an Indian lander.