Chandrayaan 2 detected noble gas Argon-40 on the Moon; it also mapped a possible Lunar lobate scarp which meant that the Moon is still warm inside as it cools
Photo: iSRO_ On July 14, 2023, Indian Space Research Organisation (ISRO) launched Chandrayaan 3, which will attempt to make a soft landing on the Moon. This follows two previous missions, Chandrayaan 1 and 2.
Chandrayaan 2, which consisted of an orbiter, a lander and a rover, was India’s first attempt to soft land on the Moon. The mission approximately cost Rs 603 crore. The eight instruments on board aimed to study the surface geology, composition and exosphere (outermost atmospheric layer) of the Moon.
On July 22, 2019, the space agency launched Chandrayaan 2 from the Satish Dhawan Space Centre (SDSC), Sriharikota.
On August 14, the spacecraft entered into Lunar Transfer Trajectory (LTT). Six days later, it entered the elliptical orbit around the Moon. On September 2, the Vikram lander separated from the Orbiter and five days later, it began its descent.
However, ISRO lost all communication from the lander and it was later revealed that it had crashed into the surface.
However, the orbiter continued to spy on the Moon. It detected Argon-40 (Ar-40), a noble gas in the lunar exosphere, according to the Indian space agency.
The origin of this noble gas can be traced back to the radiogenic breakdown of potassium-40. The gas is known to diffuse from below the lunar surface through the intergranular space and into the lunar exosphere.
Previous missions have detected Argon-40 from the equatorial and low-latitude regions of the Moon. It was first detected by the Lunar Atmospheric Composition Experiment (LACE) on Apollo-17.
ISRO’s CHandra’s Atmospheric Composition Explorer-2 (CHACE-2) also detected this noble gas in other latitude regions as well, for the first time.
Further, CHACE-2 observations showed Ar-40 was enhanced over Potassium, Rare Earth Elements and Phosphorous rich region on the Moon and the South Pole Aitken (SPA) terrain — the largest impact basin on the Moon.
ISRO called for a deeper understanding of how the surface and exosphere interact.
The Terrain Mapping Camera (TMC-2) of Chandrayaan-2 mapped a possible Lunar lobate scarp, which is a relatively small-scale tectonic landform thought to result from a thrust fault developed in rocks, according to Arizona State University.
Lobate scarps indicate that the Moon is still warm inside even as it cools. As the interior cools, it shrinks, robbing the brittle crust of support. Gravity tugs on the crust until it snaps, forming a thrust fault.
ISRO estimates that this lobate scarp could have been formed in the Copernican period, one of the five periods’ units of this timescale, which began 0.8 billion years ago to the present time.
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