Chandrayaan-4 South Pole Landing Site Identified

Scientists at ISRO’s Space Applications Centre have identified a promising landing site near Mons Mouton in the Moon’s south polar region for India’s first lunar sample return mission, Chandrayaan-4. The selection follows a detailed terrain assessment using high-resolution imagery from the Chandrayaan-2 Orbiter. A one-square-kilometre patch has emerged as the safest option for touchdown in one of the Moon’s most rugged landscapes.

High-Resolution Terrain Mapping

The study relied on images from the Orbiter High Resolution Camera (OHRC) aboard Chandrayaan-2. Stereo images with 32-centimetre resolution enabled scientists to generate precise digital elevation models at a 0.32-metre grid scale. Researchers examined surface slopes, crater density, boulder distribution and illumination conditions.

Earlier assessments had identified broad candidate zones between 84° and 90° south latitude. The latest analysis narrowed the focus to five specific regions around Mons Mouton. One was rejected due to permanent shadow, which would hinder power generation and communication.

Strict Engineering Constraints

Chandrayaan-4 will be ISRO’s most complex lunar mission. The spacecraft will consist of a propulsion module, descender module, ascender module, transfer module and re-entry module. The descender and ascender stack must soft-land, collect lunar samples and launch them back to orbit for return to Earth.

Engineers require landing slopes below 10° and boulders smaller than 0.32 metres. Adequate sunlight for 11–12 days and uninterrupted radio visibility to Earth are essential. These constraints make site selection critical in the uneven south polar terrain.

MM-4 Emerges as Front-Runner

Four shortlisted sites—MM-1, MM-3, MM-4 and MM-5—were evaluated. Parameters included average slope, elevation variation and the number of safe 24×24 metre landing grids. Elevations ranged between 4,800 and over 6,100 metres.

MM-4, located at latitude −84.289° and longitude 32.808°, showed the lowest hazard level at 9.89% and an average slope of 5°. It offered 568 safe grids, the highest among all candidates. Other sites recorded hazard levels above 12% or significantly fewer safe grids.

Important Facts for Exams

• Chandrayaan-4 aims to return lunar samples to Earth from the south polar region.
• The Orbiter High Resolution Camera (OHRC) provides 32-centimetre spatial resolution.
• Mons Mouton lies near the Moon’s south pole between 84° and 90° south latitude.
• Landing safety depends on slope limits, boulder size and adequate solar illumination.

Strategic Significance for ISRO

If approved, the MM-4 site will host India’s first lunar sample return attempt. Success would place ISRO among a small group of space agencies capable of returning extraterrestrial material. The mission would mark a major advance in India’s planetary exploration capabilities and demonstrate the value of high-resolution lunar mapping for precision landings.