China’s Chang’E-5 lander finds evidence of native water on the Moon
Samples collected China’s lunar lander Chang’E-5 have delivered the first definitive confirmation of the evidence of native water on the Moon. The lander collected samples from the Moon’s Oceanus Procellarum, an ancient mare basalt whose name means “Ocean of Storms”. An on-board spectral analysis gave the first confirmation of water signal in 2020 and this was later validated through the laboratory analysis of the samples when the lander returned in 2021. Now, the team has determined that the water originated from the moon itself.
The research has been documented in an article titled “Evidence of water on the lunar surface from Chang’E-5 in-situ spectra and returned samples” published in Nature Communications.
“For the first time in the world, the results of laboratory analysis of lunar return samples and spectral data from in-situ lunar surface surveys were used jointly to examine the presence, form and amount of ‘water’ in lunar samples. The results accurately answer the question of the dribution characterics and source of water in the Chang’E-5 landing zone and provide a ground truth for the interpretation and estimation of water signals in remote sensing survey data,” said co-corresponding author LI Chunlai, from the National Astronomical Observatories of the Chinese Academy of Sciences, in a press statement.
The lander did not find rivers or lakes on the Moon, rather, it identified 30 hydroxyl parts per million on average in rocks and soil it collected on the Moon’s surface. These molecules are the main ingredient of water and are made of one oxygen and one hydrogen atom. They are also the most common result of water molecules chemically reacting with other matter. In essence, hydroxyl is to water what smoke is to fire.Best of Express PremiumPremiumPremiumPremiumPremium
Chang’E-5 collected the samples during the hottest part of the Moon’s day with temperatures around 90 degrees celsius, when the surface should be at its driest. This timing also coincided with low solar winds, which can contribute to hydration at a high enough intensity. The hydration signals appeared even in such dehydrated conditions. So the natural question is, where did they come from?
The hydroxyl was first detected in 11 rock and soil samples and then confirmed five multi-part laboratory analyses on eight of the samples and it was found to originate from two different sources. The bulk of the hydroxyl in the Chang’E-5 samples was contained in apatite, a crystalline, phosphate-rich mineral naturally found on the Moon and on the Earth.
“This excess hydroxyl is indigenous, demonstrating the presence of lunar-originated internal water in the Chang’E-5 lunar samples, and that water played an important role in the formation and crystallization of the late lunar basaltic magma,” said Li, referring to the composition of Chang’E-5 landing site in the mare basalt of Oceanus Procellarum.
The researchers are currently planning further lunar exploration with this Chang’E-5’s successors: Chang’E-6 and Chang’E-7. They will continue to research lunar water through remote sensing, on-site detection and laboratory analysis to better understand the source, dribution and temporal variation of lunar water.
