The Chang’e-5 spacecraft landed on one of the youngest sea basalts located in mid-latitude on the Moon and delivered 1.7 kg samples. Before taking samples of the lunar soil and delivering them to Earth, the lunar mineralogical spectrometer on board the module measured the spectral reflectivity of the regolith (residual soil, which is a product of space weathering of rocks).
Water absorbs infrared radiation with a wavelength of about 2.85 microns, which makes it possible to detect its presence in the spectrum. However, thermal radiation from the lunar hot surface can mask traces of water, which is why the scientists used a thermal correction model for the spectra.
Quantitative spectral analysis showed that the lunar soil at the landing site contains less than 120 ppm water, and the light and bubble rock, which was also analyzed, showed stronger absorption at a wavelength of 2.85 μm. This corresponds to approximately 180 ppm (millionths) of water, which may indicate an additional source of water in the bowels of the moon.
Chang’e-5 is a Chinese automatic interplanetary station launched as part of an unmanned reentry mission to explore the moon. On November 23, 2020, the device was launched, on December 1, it landed on the moon, collected soil samples from the lunar surface, and on December 16, these samples were delivered to Earth, reported Space News.
In 2020, the Stratospheric Observatory of the US National Space Agency found that water is present in a cubic meter of lunar soil in amounts ranging from 100 to 412 ppm, which is equivalent to a 0.3 liter bottle of water.
–
– .
