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Chang’E-4 Probes 40 Meters Into Lunar Surface

A little over a year after landing, China’s spacecraft Chang’E-4 is continuing to unveil secrets from the far side of the Moon. The latest study, published on Feb. 26 in Science Advances, reveals what lurks below the surface. Chang’E-4 (CE-4) landed on the eastern floor of the Van Kármán crater, near the Moon’s south pole, on Jan. 3, 2019. The spacecraft immediately deployed its Yutu-2 rover, which uses Lunar Penetrating Radar (LPR) to investigate underground as it roams.

Paper author Li Chunlai, a research professor and deputy director-general of the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC), said:

Li and his team used the LPR to send radio signals deep into the surface of the Moon, reaching a depth of 40 meters using a 500 MHz high-frequency channel — more than three times the depth previously reached by CE-3. This data allowed the researchers to develop an approximate image of the subsurface stratigraphy. Su Yan, a corresponding author who is also affiliated with NAOC, said:

The researchers combined the radar image with tomographic data and quantitative analysis of the subsurface. They concluded that the subsurface is essentially made by highly porous granular materials embedding boulders of different sizes. The content is likely the result of a turbulent early galaxy when meteors and other space debris frequently struck the Moon.

The subsurface stratigraphy seen by Yutu-2 radar on the farside of the moon. (Image: CLEP/CRAS/NAOC)
The subsurface stratigraphy as seen by Yutu-2 radar on the far side of the Moon. (Image: CLEP/CRAS/NAOC)

The impact site would eject material to other areas, creating a cratered surface atop a subsurface with varying layers. The results of the radar data collected by the LPR during the first 2 days of lunar operation provide the first electromagnetic image of the far side subsurface structure and the first “ground truth” of the stratigraphic architecture of an ejecta deposit. Li said, referring to the material ejected at each impact:

Provided by: Chinese Academy of Sciences [Note: Materials may be edited for content and length.]

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  • Troy was born and raised in Australia and has always wanted to know why and how things work, which led him to his love for science. He is a professional photographer and enjoys taking pictures of Australia's beautiful landscapes. He is also a professional storm chaser where he currently lives in Hervey Bay, Australia.

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