Bangalore, November 1: In a further remarkable achievement, the Chandrayaan-2 orbiter has detected Argon-40 on lunar exosphere. Indian Space Research Organisation (ISRO) informed yesterday. ISRO tweeted that the CHACE-2 payload aboard the Chandrayaan-2 orbiter has detected Argon-40 from an altitude of approximately 100 kilometres.
A specialised payload aboard the Chandrayaan-2 orbiter named Chandra’s Atmospheric Composition Explorer-2 (CHACE-2) has detected Argon-40 in the gaseous envelope around the Moon. CHACE-2 is a spectrometer capable of scanning the thin gaseous envelope around the Moon called the lunar exosphere with a very high mass resolution. The primary objective of this instrument is to analyse the composition and distribution of Moon’s exosphere.
Argon-40 is one of the forms of the noble gas Argon and is an important constituent of lunar exosphere. The presence of Argon is well established, and even the rock samples from NASA’s Apollo missions also contained traces of Argon. The radioactive decay of rocks deep below the lunar surface release Argon-40 which escapes to the lunar exosphere through seepages and faults. The detection of this isotope in the early days of the orbiter mission demonstrates that the instrument is functioning efficiently onboard Chandrayaan-2.
"Planetary scientists prefer to call the thin gaseous envelope around the Moon as the ‘Lunar exosphere’ since it is so tenuous that the gas atoms very rarely collide with each other. Argon-40, which is one of the isotopes of the noble gas Argon, is an important constituent of the lunar exosphere. It originates from the radioactive disintegration of Potassium-40. The radioactive nuclide, which is present deep below the lunar surface, eventually diffuses through the intergranular space and makes way up to the lunar exosphere through seepages and faults," Explained ISRO