Chandrayaan-2 equipment finds abundance of sodium on the moon 

For those of you who keep track of India’s space missions, you would definitely know about the Chandrayaan missions dedicated to lunar exploration. While Chandrayaan-1 was successfully conducted in 2008 and even made startling lunar discoveries, such as finding evidence of water on the moon’s surface, Chandrayaan-2, that was launched in July 2019 didn’t have the same fate. Instead, its lander named Vikram crashed onto the lunar surface, thus ending the mission in failure in September the same year. Interestingly, the orbiter from this mission alongside a few other equipment survived the crash and have ever since been hovering over the lunar surface, waiting to be used during the third mission. 

But now, ahead of the launch of Chandrayaan-3 in July 2023, the mission that aims to finally put an unmanned rover (named Pragyaan) on the moon and explore potential water sources near the polar regions, the Indian Space Research Organisation (ISRO) has made a brand-new discovery. Scientists from the prestigious national space agency have managed to map out the global distribution of sodium on the lunar surface, that too using the CLASS equipment, better known as the Chadrayaan-2 Large Area Soft X-ray spectrometer that was part of the Chandrayaan-2 orbiter. In fact, it has revealed abundance of this mineral on the moon, something that wasn’t known earlier.  

Sources also cite that this was a maiden attempt on part of any space agency to provide a full-scale measurement of sodium on the moon, employing advanced technology called X-ray fluorescent spectra. However, ISRO astronomers have deemed that it was a joint effort by the first two Chandrayaan missions, as it was the first’s X-ray Florescence Spectrometer or C1XS that had first detected sodium from its characteristic line in the X-rays, thus opening up the possibility of mapping the exact amount of sodium on the lunar surface, thanks to the second’s CLASS equipment.  

For those unaware, the CLASS equipment was designed and developed at the UR Rao Satellite Centre of ISRO in Bengaluru, it was able to provide clean signatures of the sodium line, due to its high sensitivity and effective performance. Simply put, it was able to find clear signals arising from thin strands of sodium atoms weakly attached to the lunar surface. Interestingly, these mineral atoms can easily be pushed out of the surface if exposed to solar winds or ultraviolet radiation. In addition, the CLASS was also able to trace diurnal variation of the sodium and how it was from the moon that this mineral was continuously supplied to the exosphere, thus sustaining its thin region.  

The recent findings have been published in The Astrophysical Journal Letters and provides a new avenue to conduct research on surface-exosphere interaction with respect to the moon, alongside developing similar techniques for discovery of mercury and other weightless minerals in and around the lunar surface.