Chennai: A team of scientists from the Physical Research Laboratory (PRL), Ahmedabad, and ISRO, has reported the first in-situ elemental abundance of lunar soil near the Southern Polar region using measurements made by the Alpha Particle X-ray Spectrometer (APXS) on the Pragyan rover of the Chandrayaan-3 mission.
This study published in the journal Nature has provided evidence that supports the Lunar Magma Ocean hypothesis, which predicts that the primordial lunar crust was formed as a result of the floatation of lighter anorthite plagioclase — but, APXS also detected higher abundance of magnesium-rich minerals, suggesting contributions from deeper layer material ejected from South Pole-Aitken basin during its formation.
The analysis from 23 measurements at different locations within 50-metre of the Chandrayaan-3 landing site--Shiv Shakti point--showed that the lunar regolith is uniform in elemental composition, and hence can serve as an excellent ground truth for future remote sensing missions, ISRO said
in an update on its website.
The Vikram Lander of the Chandrayaan-3 mission made the historic Moon landing on August 23, 2023 at 18.04 IST at the 69.37-degree South latitude and 32.35-degree East longitude (Shiv Shakti point).
The Pragyan rover deployed on lunar surface explored the nearby area by traversing about 103 meters over the next ten days.
The PRL-built scientific instrument APXS aboard the Pragyan rover was designed to measure the elemental composition of lunar soil at the locations of rover stops, by deploying the APXS close to lunar surface for measurements and stowing it back while moving.
The APXS employs the techniques of X-ray Fluorescence Spectroscopy and Particle Induced X-ray Emission to detect and quantify various major and minor elements present in lunar soil, such as Si, Mg, Al, Fe, Ca, as well as Mn, Cr, Ti, Ni, K, Na, and, S etc. By irradiating the lunar surface with its Cm-244 sources, APXS recorded characteristic X-ray lines of all major and minor elements.