ISRO-SAC instrument finds presence of hydroxyl and water molecules on Moon

Source: Indian express

Synopsis:

The discovery of hydroxyl and water molecules on the moon would help in studying its mineralogy.  

Background:

• Chandrayaan-2 has detected the unambiguous presence of hydroxyl and water molecules on the Moon.
• The findings were confirmed by a paper published in the latest issue of the fortnightly journal Current Science. The paper was authored by scientists from the Indian Institute of Remote Sensing (IIRS) in Dehradun, SAC in Ahmedabad, UR Rao Satellite Centre in Bengaluru, and ISRO.

About the Chandrayaan-2 mission:

• It was aimed to widen the scientific objectives of Chandrayaan-1 by way of soft landing on the Moon and deploying a rover to study the lunar surface. 
• However, due to a failed soft landing, the lander, rover, and the associated five payloads were destroyed.
• Nonetheless, the orbiter for mapping the lunar surface and studying the outer atmosphere of the Moon is continuously sending back crucial scientific data. 
• The mission life of the Orbiter was planned to be of one year, but has exceeded expectations and is expected to serve for seven years.

Findings of the paper:

Imaging infrared spectrometer (IIRS) onboard Chandrayaan 2 has detected the unambiguous presence of hydroxyl and water molecules on the Moon.

• IIRS is an imaging instrument that collects information from the electromagnetic spectrum for understanding the mineral composition of the lunar surface. Under this, each element possesses a ‘spectral signature’ unique to itself.
• It was developed by the Ahmedabad-based unit of Space Applications Centre (SAC) of ISRO.
• It is capable of operating in the wavelength of 0.8 to 5 micrometres, which is greater than Moon Mineralogy Mapper (M3). M3 was used in Chandrayaan 1 for detecting water and operates in the range of 0.4 to 3 micrometres. It was developed by NASA.

The formation of water and hydroxyl occurs due to interaction of solar winds with the lunar surface, a process termed as ‘space weathering’.

• Space weathering along with the impact from small meteorites often lead to chemical changes on the surface of the moon. 
• This ultimately leads to formation of either the reactive hydroxyl molecules or the more stable form of water molecules.

Significance of Discovery:

• It will provide clues to understand the various sources and water production mechanisms.
• It will also provide important inputs regarding geology and geophysics of the mantle (of the moon) in terms of their mineralogy, chemical composition, rheology and solar–wind interaction.
• The discovery is being hailed as critical for future planetary exploration and resource utilisation.