ISRO Selects Safe Lunar Site Near Mons Mouton for Sample Return

Chandrayaan-4 Landing Site – Mons Mouton Region Analysis  Youtube Link

Scientists at the Space Applications Centre have pinpointed a viable landing zone near Mons Mouton in the Moon’s south polar region for Chandrayaan-4, India’s first planned lunar sample return mission. The decision follows an intensive hazard and terrain evaluation using data from the Chandrayaan-2 .

Precision Terrain Mapping

The assessment relied on stereo imagery from the Orbiter High Resolution Camera (OHRC). With a spatial resolution of 32 centimetres, scientists generated digital elevation models at a fine 0.32-metre grid scale. Key variables included slope gradients, crater frequency, boulder distribution, and solar illumination patterns. Earlier studies had outlined broad candidate areas between 84° and 90° south latitude, but refined modelling isolated five promising sectors around Mons Mouton. One region was excluded due to permanent shadow, which limits solar power availability and communication windows.

Engineering and Mission Constraints

Chandrayaan-4 represents ISRO’s most sophisticated lunar architecture, integrating propulsion, descender, ascender, transfer, and re-entry modules. The landing stack must execute a soft touchdown, collect samples, and launch them back to orbit. Safety thresholds demand slopes under 10°, minimal elevation variance, and boulders smaller than 0.32 metres. Continuous sunlight for roughly 11–12 days and stable Earth visibility are also essential for mission success.

MM-4 as Preferred Candidate

Among shortlisted sites (MM-1, MM-3, MM-4, MM-5), MM-4 displayed the lowest hazard exposure (9.89%) and a moderate average slope of 5°. It also offered the highest number of safe landing grids, indicating superior operational margins.

Exam-Focused Points

• Chandrayaan-4 targets lunar sample return from the south polar region.

• OHRC imagery resolution: 32 centimetres .

• Landing criteria: slope limits, boulder size, illumination duration.

• Mons Mouton located within 84°–90° south latitude .

• MM-4 identified as lowest-risk landing zone.