BENGALURU: A study by scientists from the Physical Research Laboratory (PRL) and ISRO says that Chandrayaan-3, the Indian Lunar Mission, landed within a buried impact crater that is around 160km in size and 4.4km deep.
This is said to be older than the South Pole Atkin basin. A press release issued by ISRO on Tuesday said, “This buried crater is one of the oldest crater on the Moon and the Chandrayaan-3 Vikram lander and Pragyan rover landed and roved within this buried crater, which is hosting the SPA basin ejecta material and some of the most deeply excavated material on the Moon.”
According to the study titled, ‘Chandrayaan-3 landing site evolution by South Pole-Aitken basin and other impact craters’ published in the peer-reviewed journal, Icarus, said this information was revealed based on an analysis of images obtained by Navigation Cameras on Chandrayaan-3 Pragyan rover and Chandrayaan-2 Orbiter’s Optical High Resolution Camera.
Rover landing impacted nearby basins: Paper
The Chandrayaan-3 mission with the Vikram-lander and the Pragyan rover landed on the high latitude highland region near the south pole of the Moon. The landing site is 350km from the South Pole- Aitken (SPA) basin rim, an ancient and the largest impact basin in the solar system.
The Pragyan rover Navcam and Optical High Resolution Camera images gave the first clue about the linear, distal ejecta rays or groove-like structures possibly formed due to the distant impacts deposited at the Chandrayaan-3 landing site. The images of Pragyan rover revealed that the landing site is devoid of greater than 1m boulders along the traverse. The images also revealed typical highland terrain, the release said.
The scientists noted that the regional exploration around the Chandrayaan-3 landing site revealed a near semi-circular like structure, highly degraded in nature. This semi-circular structure encompassed the station, Shiv Shakti (yellow star).
Further detailed geomorphological and topographical analysis revealed that the semi-circular structure is a heavily degraded crater structure or a buried impact crater with a diameter of 160km. This semi-circular structure was highly degraded due to the mantling of thick ejecta deposits from the SPA basin and followed by many other complex craters throughout the geological history of the Moon.
The scientists also noted that due to the landing, the site had undergone a series of changes. The paper said that it impacted nearby and distant basins and complex crater ejecta material. “We found that the SPA basin is the major contributor, which deposited nearly 1400m of ejecta material and 11 other basins deposited 580m of ejecta. The other complex craters contributed up to 90m of ejecta. Meanwhile, secondary craters of a few km in diameter located adjacent to the Vikram lander contributed to 0.5m ejecta, which are crucial target material for the Pragyan rover in situ analysis,” the scientists said.