Chandrayaan-2 CHACE-2 Makes First-Ever Observation of Sun's CME Impact on Moon
AQuick answer
Chandrayaan-2's CHACE-2 first observed Sun's CME impact on lunar exosphere; density increased 10x during solar event.
Key facts
ISRO's Chandrayaan-2 CHACE-2 payload made the first-ever direct observation of Sun's Coronal Mass Ejection (CME) impact on the lunar exosphere
During a rare solar event on May 10, 2024, CMEs caused a significant increase in total pressure of the dayside lunar exosphere by more than an order of magnitude
The study was published in Geophysical Research Letters on August 16, 2025, confirming earlier theoretical models through direct observation
Discovery advances understanding of solar-lunar interactions with implications for astronaut safety during solar storms on future lunar missions
ISRO announced that Chandrayaan-2's CHACE-2 (Chandra's Atmospheric Composition Explorer-2) payload made the first-ever direct observation of the Sun's Coronal Mass Ejection (CME) impact on the lunar exosphere. During a rare solar event on May 10, 2024, a series of CMEs impacted the Moon, causing a significant increase in the total pressure of the dayside lunar exosphere.
The total number density derived from observations showed an increase by more than an order of magnitude, consistent with earlier theoretical models but observed directly for the first time. The study was published in Geophysical Research Letters on August 16, 2025. This discovery advances understanding of solar-lunar interactions and has implications for future lunar missions planning for astronaut safety on the Moon's surface during solar storms.
PYQPrelims/PYQ angle
RAS 2021 What is the difference between Polar Satellite launch vehicle and Geosynchronous Satellite launch vehicle? — Satellite launch vehicle context supports Chandrayaan mission science return questions.
Mains angle
Q: Explain the significance of Chandrayaan-2 CHACE-2's first direct observation of a coronal mass ejection impact on the lunar exosphere.
Answer (50 words): ISRO announced that Chandrayaan-2's CHACE-2 payload made the first direct observation of Sun's coronal mass ejection impact on lunar exosphere during the May 10, 2024 solar event. Total number density rose over an order of magnitude. Published in Geophysical Research Letters on August 16, 2025, it guides lunar astronaut safety planning.
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Linked questionMedium
Chandrayaan-2's CHACE-2 payload made the first-ever direct observation of which phenomenon on the lunar surface?
Explanation · Correct answer B
CHACE-2 (Chandra's Atmospheric Composition Explorer-2) made the first-ever direct observation of the Sun's Coronal Mass Ejection impact on the lunar exosphere. During a rare solar event on May 10, 2024, CMEs caused a significant increase in total pressure of the dayside lunar exosphere.
What first-ever observation did Chandrayaan-2's CHACE-2 make of the Moon?
**Chandrayaan-2's CHACE-2 (Chandra's Atmospheric Composition Explorer-2)** made the **first-ever direct observation** of the Sun's **Coronal Mass Ejection (CME) impact on the lunar exosphere** during a rare solar event on **May 10, 2024**.
What is CHACE-2 on Chandrayaan-2?
**CHACE-2 (Chandra's Atmospheric Composition Explorer-2)** is a payload on ISRO's **Chandrayaan-2** orbiter designed to study the lunar exosphere's composition. In October 2025, ISRO announced that CHACE-2 had made the first-ever observation of a CME impact on the Moon.
What happened to the lunar exosphere during the May 10, 2024 solar event?
During the rare solar event on **May 10, 2024**, a series of **Coronal Mass Ejections (CMEs)** impacted the Moon, causing the **total pressure of the dayside lunar exosphere to increase by more than an order of magnitude** — the first-ever direct observation of this phenomenon.
What is a Coronal Mass Ejection (CME) and how does it affect the Moon?
A **Coronal Mass Ejection (CME)** is a massive burst of solar plasma and magnetic fields from the Sun. When CMEs impact the Moon (which has no global magnetic field), they directly interact with the **lunar exosphere**, causing significant increases in particle density and pressure.
When did ISRO announce Chandrayaan-2 CHACE-2's historic CME observation?
**ISRO announced** the Chandrayaan-2 CHACE-2 historic observation of the Sun's CME impact on the lunar exosphere **in October 2025**. The actual solar event that was observed occurred on **May 10, 2024**, making it the first-ever direct observation of this phenomenon.
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