**ISRO's Orbiter Captures Unprecedented Solar Storm Impact, Revealing Crucial Data for Future Lunar Missions** **BENGALURU, India, October 19, 2025** — In a groundbreaking discovery that deepens our understanding of Earth's closest celestial neighbor, India's Chandrayaan-2 lunar orbiter has made the first-ever direct observation of the Sun's powerful coronal mass ejections (CMEs) impacting the Moon's incredibly thin atmosphere, known as the exosphere. This unprecedented event, captured by the orbiter's Chandra's Atmospheric Composition Explorer-2 (CHACE-2) instrument, offers vital insights into lunar space weather and the challenges of establishing human outposts on the Moon. ^[1][2][3][4]The Indian Space Research Organisation (ISRO) announced that during a rare solar event on May 10, 2024, a series of CMEs — massive bursts of solar wind and magnetic fields — slammed into the Moon. This ^[1][2][3][4]powerful impact caused a significant, temporary increase in the total pressure of the dayside lunar exosphere, with the number density of neutral atoms and molecules surging by more than an order of magnitude. These^[1][2][4] observations confirm long-held theoretical predictions, marking the first time scientists have directly witnessed such an effect. ### ^[1][2][4]The Full Story Chandrayaan-2, launched on July 22, 2019, has continued its mission to orbit the Moon, even after its Vikram lander lost communication during its landing attempt on September 7, 2019. The o^[3][5][6]rbiter remains fully operational, circling the Moon in a 100 km x 100 km orbit. Its s^[3][5][6]uite of eight scientific instruments continues to collect invaluable data, pushing the boundaries of lunar science. The ^[6]key to this recent discovery was the CHACE-2 payload, designed to study the composition and distribution of the Moon's neutral exosphere. On Ma^[3][5][4]y 10, 2024, the Sun unleashed a series of Coronal Mass Ejections, sending a wave of superheated plasma hurtling towards the Moon. Becau^[1][2][4]se the Moon lacks a global magnetic field and a substantial atmosphere like Earth's, it is highly vulnerable to such solar assaults. When^[1][5][6][7] the CMEs hit, they essentially "knocked off" atoms from the lunar surface, releasing them into the exosphere and causing the observed spike in atmospheric pressure. This ^{[1][2][5][4][6]}phenomenon is particularly significant because the Moon's exosphere is a "surface boundary exosphere," meaning its boundary is the lunar surface itself, making it extremely sensitive to external forces like solar activity. The s^[1][4]tudy detailing these findings, titled “Impact of a Coronal Mass Ejection on the Lunar Exosphere as Observed by CHACE-2 on the Chandrayaan-2 Orbiter,” was published in Geophysical Research Letters on August 16, 2025. ### What^[1][3] This Means This isn't just a fascinating scientific tidbit; it has tangible implications for humanity's future in space. For starters, it gives us a much clearer picture of "lunar space weather" – how the Sun's emissions affect the Moon's environment. But here's^[1][2][5][4] the thing: understanding these solar impacts is crucial for anyone dreaming of living or working on the Moon. ISRO scientists emphasized that these observations highlight the challenges of building scientific bases or human habitats on the lunar surface. Lunar archi^{[1][2][5][4][6]}tects and mission planners now need to factor in such extreme, temporary alterations to the lunar environment when designing long-term settlements. It means en^[2][5][6]gineers must consider how future lunar structures and equipment will withstand periods of increased radiation and atmospheric density before these effects naturally subside. **Key Points:** * Chandrayaan-2's CHACE-2 instrument made the first direct observation of solar coronal mass ejections (CMEs) impacting the Moon's exosphere. * A serie^[1][2][3][4]s of CMEs on May 10, 2024, caused the Moon's dayside exosphere pressure to increase by more than an order of magnitude. * The Moo^[1][2][4]n's lack of a global magnetic field makes its thin atmosphere highly vulnerable to solar activity. * This di^[1][5][6][7]scovery is critical for designing future human habitats and scientific bases on the Moon, as it reveals temporary but significant changes to the lunar environment. ### The Bi^{[1][2][5][4][6]}gger Picture The Sun's influence on the Moon is profound and multifaceted. Beyond these newly observed CME impacts, solar wind constantly interacts with the lunar surface. The Moon, without Earth's protective atmosphere and magnetic field, experiences a "sunburn" from solar radiation. This solar ^[8][7]wind also plays a role in creating water on the Moon, as protons from the Sun can combine with oxygen atoms on the lunar surface to form hydroxyl and water molecules. Chandrayaan^[9][7]-2 has previously detected water and hydroxyl ions on the Moon, particularly in sunlit regions. What's mor^[10]e, solar wind can charge the Moon's surface with static electricity, which can even levitate dust. This dynami^[7]c interplay between the Sun and Moon is a continuous process, shaping the lunar landscape and its tenuous atmosphere. Other instruments on Chandrayaan-2, like the Dual-Frequency Synthetic Aperture Radar (DFSAR), have been busy mapping lunar features and searching for subsurface water-ice, especially in the polar regions. These combi^[10][11][12]ned observations paint a comprehensive picture of a Moon that is far from static. ### What Happens Next? Scientists at ISRO and around the world will continue to analyze the data from CHACE-2 and Chandrayaan-2's other instruments. These findings will feed into global efforts to establish a sustained human presence on the Moon, including NASA's Artemis program and other international missions. Expected developments include refined models of lunar space weather and enhanced safety protocols for astronauts and equipment. Researchers will be watching for similar solar events to see if these observations are consistent, further validating the findings and allowing for more detailed studies of the Moon's exospheric response. The long-term operation of Chandrayaan-2's orbiter provides a unique platform for continuous monitoring, helping us to understand how our celestial neighbor truly breathes under the Sun's powerful gaze. This ongoing vigilance is essential as humanity sets its sights on returning to and eventually settling on the Moon.

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