India’s Chandrayaan-2 Makes Historic Solar Storm Observation on Moon
India’s Chandrayaan-2 lunar orbiter has achieved a major space science breakthrough by making the first-ever direct observation of how solar storms impact the Moon’s environment.
Key Findings
- CHACE-2 instrument detected increased pressure in Moon’s dayside exosphere during solar storm
- Observation confirms long-standing theoretical predictions about solar-moon interactions
- Discovery provides crucial data for future lunar missions and base planning
The Chandra’s Atmospheric Composition Explorer-2 (CHACE-2) instrument aboard Chandrayaan-2 recorded significant changes in the Moon’s extremely thin atmosphere when a Coronal Mass Ejection (CME) from the Sun struck the lunar surface.
“Observations from CHACE-2 showed an increase in the total pressure of the dayside lunar exosphere when the CME impacted the Moon,” ISRO stated on October 18.
The total number density of neutral atoms and molecules showed a substantial increase, matching earlier theoretical models that had predicted such effects but had never been directly observed until now.
Mission Background and Significance
Launched on July 22, 2019, from Sriharikota using the GSLV-MkIII rocket, Chandrayaan-2 successfully entered lunar orbit on August 20, 2019. While the Vikram lander is no longer functional, the orbiter continues to operate perfectly in its 100 km x 100 km orbit around the Moon.
The Moon’s exosphere represents one of the most fragile atmospheric environments in our solar system. As a “surface boundary exosphere,” its outer limit is the lunar surface itself, making it highly sensitive to solar activity.
Understanding Solar Storms and Lunar Impact
Coronal Mass Ejections are massive eruptions of solar material – primarily hydrogen and helium ions – from the Sun’s corona. These events have particularly dramatic effects on the Moon because it lacks both a substantial atmosphere and a global magnetic field that could provide protection.
The historic observation occurred during a rare series of coronal mass ejections on May 10, 2024. The increased solar material striking the Moon enhanced the process of knocking atoms off the lunar surface, liberating them into the exosphere and causing the observed pressure increase.
“This observation would provide scientific insight into the understanding of the lunar exosphere and space weather effects on the Moon,” ISRO noted, adding that it “also indicates the challenges of building scientific bases on the Moon.”
This breakthrough discovery not only advances our fundamental understanding of lunar space weather but also has practical implications for future lunar exploration and the establishment of permanent scientific outposts on the Moon.
