In a pioneering achievement, the Indian Space Research Organisation (ISRO) has announced that its Chandrayaan-2 mission has recorded the first-ever direct evidence of Coronal Mass Ejections (CMEs) impacting the Moon’s exosphere. This remarkable feat, previously unaccomplished by any other space agency, underscores ISRO’s advanced capabilities in space science.
The CHACE-2 instrument on the Chandrayaan-2 orbiter was instrumental in capturing this significant event. During a potent solar storm on May 10, 2024, multiple CMEs bombarded the Moon. This interaction led to a substantial rise in the total pressure within the Moon’s day-side exosphere, its extremely thin outer layer. ISRO’s analysis revealed that the density of neutral atoms and molecules in this exosphere surged by over an order of magnitude, confirming hypotheses that had lacked empirical validation until now.
The Moon’s exosphere, characterized as a surface-boundary exosphere, is particularly vulnerable to solar phenomena because it lacks a protective global magnetic field. The recent CME event effectively energized the lunar surface, releasing more atoms and molecules into the exosphere. This detailed documentation by Chandrayaan-2 provides critical data for future lunar exploration and the development of lunar bases. The research, published in Geophysical Research Letters, positions India at the forefront of lunar science.