A new study finds 40,000 square kilometers of the lunar surface has the capacity to hold water, which is about double previous estimates.
0.15% of the lunar surface is permanently shadowed, with ~10% of this area distributed in patches smaller than 100 m, that is at scales smaller than previously mapped by LOLA topography-based illumination models. The most numerous cold traps on the Moon are ~1 cm in scale.
The abundance of small-scale cold traps implies that future missions exploring for ice may more easily target and access one of these potential reservoirs. Given the high loss rates due to micrometeorite impact gardening and ultraviolet photodestruction37, the detection of water within the micro cold traps would imply recent accumulation. Therefore, the presence or absence of water in micro cold traps could serve as an indicator of volatile sources in the inner Solar System. If water is found in micro cold traps, the sheer number and topographic accessibility of these locales would facilitate future human and robotic exploration of the Moon.
Water ice is thought to be trapped in large permanently shadowed regions in the Moon’s polar regions, due to their extremely low temperatures. Here, we show that many unmapped cold traps exist on small spatial scales, substantially augmenting the areas where ice may accumulate. Using theoretical models and data from the Lunar Reconnaissance Orbiter, we estimate the contribution of shadows on scales from 1 km to 1 cm, the smallest distance over which we find cold-trapping to be effective for water ice. Approximately 10–20% of the permanent cold-trap area for water is found to be contained in these micro cold traps, which are the most numerous cold traps on the Moon. Consideration of all spatial scales therefore substantially increases the number of cold traps over previous estimates, for a total area of ~40,000 km2, about 60% of which is in the south. A majority of cold traps for water ice is found at latitudes over 80° because permanent shadows equatorward of 80° are typically too warm to support ice accumulation. Our results suggest that water trapped at the lunar poles may be more widely distributed and accessible as a resource for future missions than previously thought.
SOURCES- Nature Astronomy
Written By Brian Wang, Nextbigfuture.com