Isro scientists detect possible subsurface ice near Moon’s south pole using Chandrayaan-2

This discovery highlights the continued success and utility of the Chandrayaan-2 mission, specifically its orbiter, which remains operational. The use of the Dual Frequency Synthetic Aperture Radar (DFSAR), an L-band and S-band microwave imaging instrument, was crucial. This instrument, the first fully polarimetric synthetic aperture radar sent to the Moon, allows scientists to differentiate between actual ice signals and rough terrain by analyzing Circular Polarisation Ratio (CPR) and Degree of Polarisation (DOP). This demonstrates India's advanced capabilities in remote sensing and planetary exploration. For UPSC, understanding the specific instruments on ISRO missions and their functions is essential for Prelims.

The focus of this research is on the Moon's Permanently Shadowed Regions (PSRs), particularly 'doubly shadowed craters' near the lunar south pole. Because the Moon's axis is only slightly tilted, sunlight strikes the poles at a very low angle, creating deep craters that never receive direct sunlight. These areas maintain extremely low temperatures (around 25 Kelvin), acting as cold traps that can preserve volatile substances like water ice over billions of years. Understanding the topography and unique environmental conditions of the lunar south pole explains why it is the primary target for contemporary lunar missions, including Chandrayaan-3 and upcoming international efforts.

The presence of water ice on the Moon has significant implications for space geopolitics and future exploration. Water can be broken down into hydrogen and oxygen, providing crucial resources for life support and, importantly, rocket fuel. This concept of In-Situ Resource Utilisation (ISRU) is vital for long-term lunar habitation and deep space missions, significantly reducing the cost and complexity of launching materials from Earth. This discovery by ISRO strengthens India's position in the global space race, adding to the growing international interest from agencies like NASA and China in establishing a sustained presence at the lunar south pole.