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 > 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.

由于水冰极低的温度，据认为它们被困在月球两极地区的永久阴影区域中。在这里，我们显示出许多未映射的冷阱存在于较小的空间尺度上，从而大大增加了可能积聚冰的区域。使用理论模型和来自“月球侦察轨道”的数据，我们估计了阴影在1 km至1 cm尺度上的贡献，这是我们发现冷阱对水冰有效的最小距离。这些微冷阱中约有10％至20％的水为永久性冷阱，这些微冷阱是月球上数量最多的冷阱。因此，考虑到所有空间尺度，总面积约为40,000 km ²，大大增加了冷阱数量，超过了先前的估计。，其中约60％位于南部。在大于80°的纬度处发现了大多数用于水冰的冷阱，因为80度赤道的永久阴影通常太暖而无法支撑冰的积累。我们的结果表明，被困在月球两极的水可能比以前认为的更广泛地分布和可作为未来任务的资源。