月球上有水吗？嫦娥五号揭示着陆区月表水含量
月球上有水吗？由中科院地质地球所行星科学团队与上海技术物理研究所、国家空间科学中心、夏威夷大学、南京大学合作的科研团队合作，通过对嫦娥五号所携带“月球矿物光谱分析仪”探测的数据进行研究，首次获得了月表原位条件下的水含量。
最新研究显示，1吨月壤中约有120克“水”，1吨岩石中约有180克水。这一研究成果2022年1月8日在《科学-进展》上发表。科研团队介绍，光谱仪所探测到的水指矿物里的水分子或者羟基，在一定条件下才能转化为可以喝的水。
Chinese scientists published results of in-situ detection of water signals on the moon by the Chang'e-5 lunar lander, lending new evidence to the dryness of the satellite.
The study published on Saturday in the peer-reviewed journal Science Advances revealed that the lunar soil at the landing site contains less than 120 parts per million water or 120 grams of water per tonne, and a light, vesicular rock carries 180 parts per million, which are much drier than that on Earth.
2020年12月，嫦娥五号探测器成功着陆在了月球风暴洋北部地区，并将1731克的月球样品返回地球，基于样品的实验室研究，确定了着陆区玄武岩的年龄约为20亿年。除了采集月球样品返回地球之外，嫦娥五号探测器的另外一个重要任务是在原位条件下获取采样区的形貌与物质成分，解析月表水特征。月表水的探测对于约束月球的形成过程、月球科研站建设和原位资源利用等都至关重要。
经过半个多世纪的争论和探测，各种“实锤”证据让人们相信月球上是有水存在的，但月球水的含量、来源等仍是需要研究的问题。光谱技术是目前探测月球水及其分布较为直接的方式。此前，来自光谱仪的数据都是从距离月面遥远的月球上空观测到的证据，人类还从来没有在月球表面原位直接进行过水的探测。嫦娥五号探测器携带了月球矿物光谱分析仪，在采样过程中获取了月表的光谱，第一次有机会在月表近距离、高分辨的探测水的信号。
科研团队介绍，嫦娥六号、嫦娥七号将在原位和轨道尺度继续探测月表水的含量、分布，这一研究成果也将为嫦娥六号、嫦娥七号的科学目标实现提供支撑。
A device onboard the lunar lander measured the spectral reflectance of the regolith and the rock and detected water on the spot for the first time.
The water content can be estimated since the water molecule or hydroxyl absorbs at a frequency of about three micrometers, according to researchers from the Chinese Academy of Sciences (CAS).
It was the solar wind that contributed to the most humidity of lunar soil, as it brought hydrogen that makes up the water, the researchers said.
The additional 60 parts per million water in the rock may originate from the lunar interior, according to the researchers.
Therefore, the rock is estimated to hail from an older, more humid basaltic unit before being ejected onto the landing site to be picked up by the lunar lander.
The study revealed that the moon had turned drier within a certain period, owing probably to the degassing of its mantle reservoir.
The Chang'e-5 spacecraft landed on one of the youngest mare basalts located at a mid-high latitude on the moon. It measured water on the spot and retrieved samples weighing 1,731 grams.
The results are consistent with a preliminary analysis of the returned Chang'e-5 samples, according to the study.
The findings provide more clues to China's Chang'e-6 and Chang'e-7 missions. The investigations of lunar water reserves come into the limelight as the building of manned lunar stations are in the pipeline in the next decades.