Chandrayaan-2 detects possible presence of subsurface ice near south pole of moon

📌 Summary:

• Nearly six years after launch (2019), Chandrayaan-2 orbiter continues delivering science from lunar orbit

• New finding: possible presence of subsurface ice in the Moon's south polar region

• Discovery made by scientists at the Physical Research Laboratory (PRL), Ahmedabad

• Instrument used: Chandrayaan-2's Dual Frequency Synthetic Aperture Radar (DFSAR) payload — capable of penetrating the lunar regolith and sensing buried ice signatures

• Significance: builds the scientific case for water ice reservoirs at the lunar south pole, strengthening the case for Chandrayaan-4 and future crewed lunar exploration

🎯 UPSC Relevance: GS3 S&T — Indian space programme, ISRO missions, scientific applications of remote sensing; long-tail returns from Chandrayaan-2 even after Vikram lander loss

📝 Prelims Facts:

• Chandrayaan-2 launched: 22 July 2019; orbiter still operational in lunar orbit
• DFSAR = Dual Frequency Synthetic Aperture Radar (L and S band) — Chandrayaan-2's radar payload
• PRL = Physical Research Laboratory, Ahmedabad — autonomous unit under DoS, headed by ISRO
• Subsurface ice = water ice buried under lunar regolith, distinct from surface frost
• South pole of Moon is the focus for Chandrayaan-3, Chandrayaan-4 and NASA Artemis missions because of permanently shadowed regions (PSRs) that can host ice

🔑 Key Term: Synthetic Aperture Radar (SAR) — active microwave imaging technique that uses platform motion to synthesise a large effective antenna; can penetrate clouds, dust and a few metres of regolith, ideal for detecting subsurface ice.