Variation of In-Situ Partial Pressures of Different Gases Over Southern Polar Region of Moon Utilizing Chandrayaan-2 Data

Chandrayaan-2 was India's first robotic and exploration mission to attempt a soft landing in the Southern Hemisphere of Moon. This paper provides insight into the Chandrayaan-2 mission through analysis of in-situ partial pressures of different gases over exosphere of lunar surface. Chandra's Atmospheric Composition Explorer-2 (CHACE-2) experiment in the Chandrayaan-2 orbiter was aimed at studying, in-situ the different gases (1–300 amu with a maximum adjustment of 0.5 amu) of the neutral lunar exosphere. We analyse partial pressures of ten different gases including Mg, Al, Ca, Ar, H2, He, H2O, H2SO4, N2, Na, and Si for different seasons of 2020. The results in case of argon suggest that the semi-annual variation of inert gas like Ar was consistent with condensation loss in the seasonal cold traps at the poles that was due to the obliquity of the Moon. A two-tailed unequal variance student t-test has been applied on the partial pressure data of different gaseous elements over lunar surface to know the difference between means of various seasons. From the observations, the partial pressure was found to be low during JF, while it started increasing as soon as MAM approached. It was because partial pressure depends on temperature like Earth’s atmospheric gases. The results also brought out the importance of the surface–exosphere interaction process.