ISRO Chandrayaan-2’s CHACE-2 Observations

In a remarkable scientific achievement, the Indian Space Research Organisation (ISRO) has confirmed that its Chandrayaan-2 lunar orbiter, equipped with the CHACE-2 instrument, has made the first-ever direct observation of how solar activity, specifically coronal mass ejections (CMEs), impacts the Moon’s exosphere.

This discovery provides unprecedented insight into lunar space weather, the Moon’s atmosphere, and its surface-boundary exosphere, which is crucial for SSC aspirants preparing for current affairs and science-related topics.

What Is CHACE-2?

CHACE-2 (Chandra’s Atmospheric Composition Explorer-2) is a highly sophisticated instrument aboard Chandrayaan-2 designed to study the lunar exosphere. Building on the success of its predecessor from Chandrayaan-1, CHACE-2 measures the number density of neutral atoms and molecules, the pressure of the Moon's atmosphere, and their response to solar wind and space weather events.

This instrument has played a pivotal role in enabling ISRO to understand how external factors, such as solar activity, coronal mass ejections, and space weather effects, affect the Moon’s delicate exosphere.

Understanding Coronal Mass Ejections (CMEs)

Coronal Mass Ejections (CMEs) are massive bursts of plasma and magnetic fields released from the Sun’s corona. These ejections mainly consist of hydrogen and helium ions. When they reach planetary bodies, they can cause significant changes: on Earth, they disrupt satellites and power grids, while on the Moon, which lacks an atmosphere and a global magnetic field, the effects are even more direct.

According to CHACE-2 observations of the lunar exosphere, CMEs can dramatically increase the liberation of atoms from the Moon’s surface, temporarily raising the density and pressure of the Moon's atmosphere.

Chandrayaan-2 Observations: How CHACE-2 Detected Solar Impacts

On May 10, 2024, a rare series of CMEs impacted the Moon. Using CHACE-2, ISRO scientists recorded a tenfold increase in the total pressure of the sunlit lunar exosphere. This observation was significant because it validated theoretical models that had previously lacked empirical evidence.

• The findings demonstrated the lunar exosphere's response to solar storms, showing that solar outbursts can drastically alter the Moon’s atmospheric conditions.

• CHACE-2 data reveal lunar atmospheric changes by measuring how high-energy solar wind particles dislodge atoms and molecules from the lunar surface, forming part of the Moon’s thin exosphere.

• These results are a testament to ISRO’s Chandrayaan mission excellence and India’s growing contribution to Moon science.

Why the Moon’s Exosphere Is So Sensitive

Unlike Earth, the Moon is airless and lacks a global magnetic field. Its surface-boundary exosphere is extremely susceptible to fluctuations in solar activity. CHACE-2 instrument results have confirmed that the Moon's atmosphere changes significantly during solar events.

The lunar exosphere is influenced by:

• Solar radiation

• Solar wind

• Meteorite impacts

When a CME lunar observation occurs, high-energy particles bombard the Moon, enhancing the release of Moon surface atoms. This makes the exosphere a dynamic layer directly reflecting solar activity impact and space weather effects.

ISRO’s Expanding Lunar Legacy

Launched in 2019, the Chandrayaan-2 orbiter continues to deliver ISRO lunar discovery after discovery, despite the lander’s unsuccessful touchdown. The scientific significance of the CHACE-2 instrument results highlights India’s position among nations conducting advanced lunar research.

Through CHACE-2 observations of the lunar exosphere, ISRO has not only enhanced understanding of how solar activity affects the Moon’s atmosphere but also reinforced India’s growing role in planetary exploration and lunar mission achievements.

Key Takeaways for SSC Aspirants

• CHACE-2 is a critical instrument on Chandrayaan-2 for studying the lunar exosphere.

• CMEs from the Sun can significantly affect the Moon due to its lack of atmosphere and magnetic field.

• CHACE-2 data reveal lunar atmospheric changes, including a temporary tenfold increase in exosphere pressure.

• The Moon's atmosphere changes are influenced by solar wind, radiation, and meteorite impacts.

• This discovery emphasises India’s role in moon science, space weather studies, and the ISRO Chandrayaan mission.

Final Thoughts

In a groundbreaking achievement, ISRO’s Chandrayaan-2 orbiter, equipped with the CHACE-2 instrument, has made the first-ever direct observation of how Coronal Mass Ejections (CMEs) affect the Moon’s exosphere. Unlike Earth, the Moon lacks an atmosphere and magnetic field, making its surface-boundary exosphere highly sensitive to solar wind and solar storms.

On May 10, 2024, CHACE-2 observations of the lunar exosphere revealed a tenfold increase in atmospheric pressure as CMEs bombarded the lunar surface, dislodging atoms and molecules.

This discovery confirms that solar activity impacts the Moon's atmosphere directly and highlights ISRO’s Chandrayaan mission success in advancing Moon science and understanding space weather effects.