Chandrayaan-2’s Orbiter Makes Historic First: Spots Sun's Solar Storm Hitting the Moon
India's Chandrayaan-2 orbiter makes a historic discovery, observing a solar storm's effect on the lunar exosphere. Learn why this changes everything for future Moon bases.
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| A visualization of the Sun's solar storm (CME) striking the Moon. The art depicts the effect on the thin lunar exosphere. (For visualization purposes only, not to scale). Photo: ISRO.gov.in |
In a stunning scientific achievement, the Indian Space Research Organisation (ISRO) has confirmed a major discovery.
India’s Chandrayaan-2 orbiter, circling the Moon for over five years, has captured a "first-ever" observation.
It directly measured the brutal impact of a solar storm as it slammed into the lunar surface.
This groundbreaking data was announced by ISRO on Saturday, October 18, 2025.
What Did Chandrayaan-2 Discover?
The orbiter used its powerful CHACE-2 instrument to get the data.
(CHACE-2 stands for Chandra’s Atmospheric Composition Explorer-2.)
It found that when a solar storm hit the Moon, the pressure of the Moon's thin atmosphere (exosphere) shot up dramatically.
ISRO stated the number of atoms in the exosphere "showed an increase by more than an order of magnitude."
This is a massive jump. It proves old theories were correct, but this is the first time it has ever been seen and measured directly.
A Rare Solar Event: What is a CME?
The event was a Coronal Mass Ejection, or CME.
A CME is a giant explosion from the Sun’s outer atmosphere (the corona).
It blasts a billion tons of plasma and high-energy particles into space at millions of miles per hour.
Why the Moon is So Exposed
When a CME hits Earth, we are mostly safe.
Our planet's strong magnetic field acts like a shield, deflecting the dangerous solar wind.
The Moon has no global magnetic field. It has no thick atmosphere. It is completely exposed and takes the full force of the storm.
How CHACE-2 Captured the "Smoking Gun"
The observation happened during a rare event on May 10, 2024.
On that day, the Sun released a series of powerful CMEs that traveled directly toward the Moon.
CHACE-2 was in the perfect position to watch what happened next.
The Moon's "Surface Boundary Exosphere"
The Moon's "air" is called a surface boundary exosphere. It's extremely thin.
This exosphere is created when solar wind and tiny meteorites hit the lunar soil.
These impacts "knock off" atoms from the surface, which then float around as a thin atmosphere.
The CME was like a super-powered version of this. The massive blast of solar particles violently stripped atoms from the lunar surface.
This flooded the exosphere with new material, which CHACE-2 measured as a huge spike in pressure and density.
Why This Discovery is a Game-Changer
This finding is not just good science; it is vital for humanity's future.
- Understanding Space Weather:
We finally have real data on how the Sun affects the Moon. This helps scientists understand "space weather" on airless bodies.
- A Warning for Future Moon Bases:
This is the most critical part.
Nations like the USA (with the Artemis program) and China are planning to build human bases on the Moon.
ISRO warned that these solar storms "temporarily alter the lunar environment."
Any future moon base or astronaut on the surface will be exposed to these violent events.
Architects must now design habitats that can protect humans from this radiation and environmental damage.
The Orbiter That Keeps on Giving
The Chandrayaan-2 mission launched in July 2019.
While the Vikram lander faced a hard landing, the Orbiter has been a spectacular success.
It continues to circle the Moon, using its eight scientific instruments to send back priceless data.
This latest discovery proves the mission's long-term value and solidifies India's position as a major space-faring nation.
