Chandrayaan-2 gauges sodium content on Moon’s surface

Scientists from ISRO have mapped out the global distribution of sodium on the Moon’s surface using the CLASS instrument (Chandrayaan-2 large area soft X-ray spectrometer).

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Chandrayaan-2 gauges sodium content on Moon’s surface: Relevance for UPSC Exam

General Studies III- Achievements of Indians in S&T

Chandrayaan-2 gauges sodium content on Moon’s surface: Context

Scientists from ISRO have mapped out the global distribution of sodium on the Moon’s surface using the CLASS instrument (Chandrayaan-2 large area soft X-ray spectrometer) onboard of the Chandrayaan-2 mission.

This is the first effort to provide a global-scale measurement of sodium on the lunar surface using X-ray fluorescent spectra.

Chandrayaan-2

Chandrayaan-2 consisted of an Orbiter, Lander and Rover, all equipped with scientific instruments to study the moon.
The Orbiter would watch the moon from a 100-km orbit, while the Lander and Rover modules were to be separated to make a soft landing on the moon’s surface.
ISRO had named the Lander module as Vikram, after Vikram Sarabhai, the pioneer of India’s space programme, and the Rover module as Pragyaan, meaning wisdom.
The Orbiter part of the mission has been functioning normally. It is carrying eight instruments.
Each of these instruments has produced a handsome amount of data that sheds new light on the moon and offers insights that could be used in further exploration.

X-Ray Fluorescence

It is commonly used to study the composition of materials in a non-destructive manner.
When the sun gives out solar flares, a large amount of X-ray radiation falls on the moon, triggering X-ray fluorescence.
The CLASS measures the energy of the X-ray photons coming from the moon and counts the total number.
The energy of the photons indicates the atom (for instance, sodium atoms emit X-ray photons of 1.04 keV) and the intensity is a measure of how many atoms are present.

Presence of Sodium on Moon: Significance

Sodium can be used as a tracer of the volatile history of the moon.
When compared to Earth, the moon is significantly depleted of volatile elements such as sodium.
The amount of volatiles on the moon today can be used to test formation scenarios of the Earth-Moon system.