Just a year and a half ago, the Vikram landing module of the Chandrayaan-3 spacecraft successfully landed near the Moon's south pole, at about 69 degrees latitude, placing India at the forefront of the race to build settlements beyond our planet.
The lunar south pole had become the trendy destination for major space powers, attracted by its frozen water masses. The evidence of its existence is solid and has been remotely confirmed since 2019. Even the areas are mapped according to their abundance. But now, according to the results obtained by Chandrayaan-3, ice is present just a few centimeters below the surface in more areas of the lunar polar regions than previously believed. All this is due to significant variations in surface temperatures in very localized areas.
The results, just published in Communications Earth & Environment, represent a significant advancement in the future exploration and even long-term habitability of the Moon. Most of the ice discovered so far was located in the shadow of craters, where temperatures never exceed -156 degrees Celsius, due to the Moon's slight axial tilt preventing sunlight from reaching those regions.
Researcher Durga Prasad and colleagues analyzed temperature readings taken on the lunar surface and at a depth of 10 centimeters, discovering that temperatures at the Chandrayaan-3 landing site, a slope facing the Sun at a 6° angle, reached a maximum of 82 degrees but dropped to -168 during the lunar night. However, a lower maximum temperature of 59 degrees was later measured in a flat region just a meter from the landing module.
The authors used the collected data to derive a model of how the slope angle affects surface temperature in lunar latitudes similar to the landing site. The model indicated that, for slopes facing away from the Sun and towards the nearest pole, a slope with an angle greater than 14° can be cold enough for ice to accumulate near the surface.
These are conditions similar to those at the lunar poles, including proposed landing sites for NASA's Artemis manned missions near the lunar south pole. Last December, and as many space industry experts feared, NASA announced that it would not launch its manned Artemis 2 mission to orbit the Moon in September 2025, nor Artemis 3 in 2026, which was to land on the lunar surface for the first time since the Apollo program concluded in 1972, postponing the mission until at least mid-2027.
With the Chandrayaan-3 results, Indian researchers suggest that areas on the Moon where ice can form may be much more numerous and easily accessible than previously believed.
The lunar south pole is a frozen region that could become a significant source of massive supply of oxygen, hydrogen, and water that would allow, in addition to permanent colonies, the launch of future missions from its surface. The strategic interest of major space powers has surged in the last five years. In the poles, there are abundant craters everywhere, areas completely in darkness making the use of solar panels absurd, and temperatures can drop below -230 degrees Celsius.