ISRO on Chandrayaan-2: Chandrayaan-2, which has been hovering around the Moon since 2019, has mapped an abundance of sodium on the moon for the first time. The new findings from India’s second unmanned lunar mission, provide an avenue to study surface-exosphere interaction on the Moon, which would aid the development of similar models for Mercury and other airless bodies in our Solar System and beyond.Also Read – Mangalayaan Era Comes To An End, 'Is Non-Recoverable' Confirms ISRO | A Peek Into Its Long Innings
According to the Indian Space Research Organisation (ISRO), the X-ray spectrometer ‘CLASS’ on the Chandrayaan-2 orbiter mapped an abundance of sodium on the moon for the first time. “Chandrayaan-1 X-ray Fluorescence Spectrometer (C1XS) detected sodium from its characteristic line in X-rays which opened up the possibility of mapping the amount of sodium on the Moon,” the national space agency said in a statement. Also Read – India's Maiden Mars Mission 'Mangalyaan' Runs Out of Fuel; ISRO Says 'Link Lost'
Findings from Chandrayaan-2 suggest there are two kinds of sodium atoms on the Moon’s surface, those that are loosely bound on the surface and those that are part of the minerals. External agents such as solar radiation liberate the loosely bound atoms more easily thus acting as a source of the atoms in the lunar exosphere. Also Read – ISRO Test Fires Hybrid Motor to Power Future Rockets
In a recent work published in ‘The Astrophysical Journal Letters’, Chandrayaan-2 mapped the abundance of sodium on the Moon for the very first time using CLASS (Chandrayaan-2 Large Area Soft X-ray Spectrometer),it added.
Built at the U R Rao Satellite Centre of ISRO in Bengaluru, CLASS provides clean signatures of the sodium line thanks to its high sensitivity and performance. The study finds that a part of the signal could be arising from a thin veneer of sodium atoms weakly bound to the lunar grains.
These sodium atoms can be nudged out of the surface by solar wind or ultraviolet radiation more easily than if they were part of the lunar minerals. Also shown is a diurnal variation of the surface sodium that would explain the continuous supply of atoms to the exosphere, sustaining it, the statement said.
An interesting aspect that widens the interest in this alkali element is its presence in the wispy atmosphere of the moon, a region so thin that the atoms there rarely meet.
This region, termed an ‘exosphere’, begins at the surface of the moon and extends several thousand kilometres merging into the interplanetary space, the statement noted.
“The new findings from Chandrayaan-2, provide an avenue to study surface-exosphere interaction on the moon, which would aid development of similar models for mercury and other airless bodies in our solar system and beyond,” the ISRO said.
Chandrayaan-2, hovering in lunar orbit, had earlier discovered that the Moons ionosphere has a plasma density in the wake region, which is at least one order of magnitude more than what is present on the day side. The spacecraft has been studying the lunar surface ever since it arrived in orbit in 2019.