18 Oct 2023 18:53

Luna 25 photo reveals lunar crater's walls contain more water than at its base - scientists

MOSCOW. Oct 18 (Interfax) - Analysis of an image of the lunar crater Zeeman, which was taken using equipment onboard Russia's Luna 25 spacecraft, showed that the walls of the crater contain more water ice than its base, the Russian Academy of Sciences' Space Research Institute has said.

"The Luna 25 spacecraft photographed the Zeeman crater on August 17, 2023, using STS-L equipment created by the Russian Academy of Sciences' Space Research Institute. Researchers compared the photo of the crater to the available data on its surface material. The analysis showed that the material of the crater walls contains more water ice than its base does," the report said.

The Zeeman crater, which is located on the far side of the Moon near the south pole, is the third deepest crater in the Moon's southern hemisphere, the scientists said.

"The researchers compared the photos of the crater to data from the LOLA laser altimeter aboard the lunar LRO artificial satellite (NASA). According to altimetry data, the difference between different parts of the surface is also noticeable, although it is not as clear as it is in the STS-L photo. The researchers then placed a map on the crater image showing the mass share of water in the ground according to data from Russia's LEND neutron telescope, also created at the Russian Academy of Sciences' Space Research Institute and working aboard the LRO," the institute said.

According to the institute's data, the LEND device measures the neutron flow from the lunar surface, which changes depending on the concentration of hydrogen in the lunar ground. "As the main substance in the lunar ground, which contains hydrogen, is water, the LEND data can be translated into the percentage of water ice in the ground at a depth of up to one meter," the Space Research Institute said.

The scientists thus determined that the water content is smallest at the bottom of the crater, less than 0.1% of the mass, and the most "humid" parts are near the small, "freshest" strike craters which formed on the walls of the main one, where the water content is estimated at up to 0.2%.

"The image of the Zeeman crater taken by STS-L equipment shows a difference in the surface properties, which, as it turns out from detailed analysis, corresponds to the difference in the content of the water frozen in the ground," the scientists said.

The first lunar mission in Russia's contemporary history started on August 11. The Luna 25 automated interplanetary spacecraft was launched from Vostochny Cosmodrome onboard a Soyuz-2.1b launch vehicle with a Fregat booster.

Luna 25 was due to make a soft landing at the Moon's south pole on August 21, but the spacecraft was lost on August 19 after impacting with the lunar surface.

According to tentative results of the work of the intergovernmental commission investigating the Luna 25 accident, the probable cause of the spacecraft crash was an onboard command system malfunction associated with the failure of an accelerator unit, which made it impossible to shut down the spacecraft's engines on time.

The spacecraft's engine worked for 127 seconds instead of the planned 84 seconds, which caused the accident, Roscosmos head Yury Borisov said.

Borisov said on August 25 that Russia was considering repeating an automated spacecraft landing at the lunar south pole in 2025-2026 following the Luna 25 failure.

Borisov said on August 11 that the launch of Luna 26 is scheduled for 2027, Luna 27 is scheduled to be launched in 2028, and Luna 28 by 2030 or later.