Part of: Prelims and GS-III Science and technology
Context: According to the ISRO, the Chandra’s Atmospheric Composition Explorer-2 (CHACE-2) which is a quadrupole mass spectrometer onboard Chandrayaan-2 mission, has made the first-of-its-kind observations of the global distribution of Argon-40 in the weak lunar exosphere.
Key takeaways
These observations provide insight on the dynamics of the lunar exosphere, and on activities of gases emerging through radioactive decay in the first few tens of metres below the lunar surface.
The CHACE-2 observations provide the diurnal and spatial variation of Ar-40 covering the equatorial and mid latitude regions of the Moon.
Noble gases serve as important tracers to understand the processes of surface-exosphere interaction.
Argon-40 (Ar-40) is an important tracer atom to study the dynamics of the lunar exosphere species.
Ar-40 originates from the radioactive disintegration of Potassium-40 (K-40) present below the lunar surface.
Once formed, it diffuses through the inter-granular space and makes its way up to the lunar exosphere through seepages and faults.
Significant observation
NASA’s Apollo-17 and LADEE missions have detected the presence of Ar-40 in the lunar exosphere, confined to the near-equatorial region of the Moon.
As there is a steep latitudinal temperature gradient of the lunar surface, it had remained a gap area to study the pan-lunar dynamics of Moon’s exosphere, which is a temperature-driven process.
The observations by CHACE-2 on Ar-40 up to the mid-latitude regions (−60º to +60º) play a significant role to bridge the gap in the knowledge.
Chandrayaan-2
It is India’s second mission to the Moon and had failed to make a soft-landing on the lunar surface.
The lander and rover malfunctioned in the final moments and crash-landed, getting destroyed in the process.
Despite the failure, the mission’s orbiter and other parts have been functioning normally, gathering information.
Do you know?
‘Exosphere’ is the outermost region of the upper atmosphere of a celestial body where the constituent atoms and molecules rarely collide with each other and can escape into space.
