A recent study of Chandrayaan-3 mission data suggests ice deposits could exist in more locations just below the Moon’s polar surface than previously believed. Significant localised temperature variations can influence ice formation, and studying these ice particles can provide valuable information about their origins and development, according to Durga Prasad Karanam, faculty at physical research laboratory, Ahmedabad, in his statement to news agency PTI. The research was first published in the Communications Earth and Environment journal.
The Chandrayaan-3 mission, launched by Isro from Bengaluru, successfully achieved a soft landing near the lunar south pole on August 23, 2023. The landing location was subsequently designated as ‘Shiv Shakti Point’ on August 26, that same year. The landing occurred at approximately 69 degrees south latitude, near the moon’s south polar region.
At the landing site, situated on a six-degree Sun-facing slope, temperatures fluctuated between 82 degrees Celsius at peak and -170 degrees Celsius during night-time. Meanwhile, a flat surface merely a metre away from the landing spot recorded peak temperatures of about 60 degrees Celsius. The slope conditions align with the targeted proposed sites for Nasa’s Artemis mission to the moon’s south pole., which if successful will establish the first long-term lunar presence and pave the way for sustainable space exploration, according to Nasa.
Meanwhile, the Chandrayaan-3 researchers examined temperature readings from the surface and up to 10 centimetres below using the ‘ChaSTE’ probe installed on Chandrayaan-3’s Vikram lander. According to Isro, ChaSTE (Chandra’s Surface Thermophysical Experiment) analyses the temperature patterns of the lunar topsoil near the pole to study the moon’s surface thermal characteristics. The device consists of a temperature probe with a regulated penetration system that can reach 10 cm below the surface. The probe contains 10 distinct temperature sensors.
Karanam explained that the slight incline resulted in enhanced solar radiation at the ChaSTE measurement point. The team created a model to understand how slope angles affect surface temperature at high lunar latitudes, similar to the landing site’s position. Their model showed that slopes angled beyond 14 degrees, facing away from the Sun and towards the nearest pole, could maintain sufficiently cool temperatures for near-surface ice accumulation. This suggests ice could potentially form and be accessed at numerous lunar locations more readily than previously considered.
Further addressing PTI’s query about ice-to-water conversion on the Moon, Karanam explained, “Water in liquid form cannot exist on the lunar surface because of (an) ultra-high vacuum. Therefore, ice cannot transform into liquid, but would rather sublimate to vapour form.” “As of the present understanding, Moon might not have had habitable conditions in the past,” Karanam stated.
Nevertheless, ice remains a crucial resource for future lunar exploration and habitability, necessitating additional measurements like those from ChaSTE for comprehensive understanding.
“Techniques and strategies need to be developed for extraction and usage of ice for long term sustainability on the Moon,” the lead author noted.
Additionally, the authors wrote, “ChaSTE findings not only indicate fine scale spatial variability in regolith temperatures but also suggest that high-latitude regions are potential sites for scouting water-ice, resource prospecting and habitation.” “Such sites are not only scientifically interesting but also pose less technical challenges for exploration in comparison with regions closer to the poles of the Moon,” they added.