New research based on data from India’s Chandrayaan-3 mission suggests that ice may be present at more locations beneath the Moon’s surface near the poles than previously believed. The study, published inCommunications Earth and Environment, highlights how local temperature variations can influence ice formation, shedding light on its origins and movement over time.
Lead author Dr Durga Prasad Karanam, from the Physical Research Laboratory in Ahmedabad, explained that examining these ice particles could reveal insights into the Moon’s early geological history. The study analysed temperature readings taken at depths of up to 10 centimetres beneath the lunar surface, recorded by the ‘ChaSTE’ probe aboard the Chandrayaan-3 Vikram lander.
Chandrayaan-3, launched by the Indian Space Research Organisation (ISRO) from Bengaluru, successfully achieved a soft landing on the Moon’s south pole on 23 August 2023. The landing site, later named ‘Shiv Shakti Point’, sits at approximately 69 degrees south latitude.
Temperature fluctuations and ice formation
The research team found that surface temperatures at the landing site varied dramatically, with daytime peaks reaching around 82 degrees Celsius and plunging to -170 degrees Celsius at night. Just a metre away from the landing point, on a flatter surface, peak temperatures were lower, around 60 degrees Celsius.
Notably, the difference in temperatures was attributed to the lander’s location on a slight incline, which increased solar radiation exposure. This led the researchers to develop a model assessing how slope angles influence surface temperatures at high lunar latitudes. Their findings indicate that slopes facing away from the Sun, at an angle of 14 degrees or greater, may be cold enough to allow ice to accumulate near the surface.
Implications for future lunar missions
The study’s findings have significant implications for future lunar exploration, including NASA’s planned Artemis missions, which aim to land astronauts near the Moon’s south pole. The researchers suggest that ice could be more widespread and accessible than previously assumed, potentially serving as a vital resource for future human exploration and habitation.
However, Dr Karanam clarified that liquid water cannot exist on the Moon due to the extremely low atmospheric pressure, meaning that ice would sublimate directly into vapour rather than melting into liquid form. He emphasised the need for further measurements and innovative techniques to extract and utilise ice for long-term lunar sustainability.
The study’s authors concluded that the ChaSTE findings indicate fine-scale variations in lunar regolith temperatures and highlight high-latitude regions as promising locations for water-ice scouting and resource prospecting. They noted that such sites could be scientifically valuable while also posing fewer technical challenges compared to regions closer to the Moon’s poles.
