AHMEDABAD: Chandrayaan-3‘s Chandra’s Surface Thermophysical Experiment (ChaSTE) provided unprecedented in-situ temperature measurements from a high-latitude lunar regolith (soil), shedding new light on the Moon’s thermal environment and the potential for water-ice deposits.
ChaSTE, riding the Vikram lander, measured surface temperatures of up to 355K (82°C) at the lunar south pole region – 25K higher than the expected 330K. Scientists attribute this increase to the lander’s placement on a sunward-facing local slope of 6°.
“Water-ice prospecting is a crucial step in unlocking Moon’s potential for supporting human habitat and furthering exploration. Lunar temperatures not only dictate water-ice but also drive other aspects of science and exploration,” K Durga Prasad from Isro’s Physical Research Laboratory (PRL) told TOI.
He pointed out that prior to the Chandrayaan-3 mission, global lunar temperatures were mapped through remote sensing, but direct in-situ measurements were limited to the Apollo 15 and 17 missions, which primarily focused on equatorial regions. ChaSTE’s new data bridges this critical knowledge gap.
“This discovery highlights how small-scale topographical variations at high latitudes can significantly alter surface temperatures, a phenomenon less pronounced in equatorial regions,” Prasad said.
“The low thermal conductivity of the lunar regolith acts as a blanket, causing significant temperature variations within just a few centimetres of the surface. “By measuring these temperature gradients, ChaSTE not only refined our understanding of lunar surface conductivity but also provided crucial data for future missions seeking sustainable exploration solutions,” he said.
The new findings from the team, including prasad, chandan kumar, amby g, kalyana reddy p, sanjeev k mishra, janmejay kumar, dinakar prasad vajja, aasik, tinkal lady, arpit patel, arpit patel, arpit patel, arpit svs, ametabha, PRL Director Anil Bharadwaj, was published in the Journal Nature Communications Earth & Environment.
Using numerical models based on ChaSTE’s observations, the team suggests that larger poleward-facing slopes exceeding 14° may provide stable conditions for water-ice deposits. These areas receive less solar radiation and thus maintain lower temperatures, making them more viable for future lunar exploration and potential human habitation.
“Unlike the extreme polar regions, these sites offer a technically less challenging yet scientifically valuable alternative for resource prospecting… Understanding lunar thermophysics is essential for multiple reasons, including mission safety, resource exploration, and long-term habitat establishment,” Prasad said.
