Even though India’s historic lunar-landing bid, the Chandrayaan-2 mission may have had a fatal ending on the moon, the orbiter that remained active and currently orbiting the moon, is now used by the scientists for high and low, new discoveries from the lunar surface. The latest revelation of the orbiter is detecting the presence of hydroxyl and water molecules on the surface of the Moon.
According to a paper published in ‘Current Science’, the Indian Space Research Organisation’s (ISRO) indigenous instrument has detected the unambiguous presence of hydroxyl (OH) as well as water molecules (H20) on the lunar surface with the precision of differentiating between the two. In order to achieve precision in distinguishing between hydroxyl and water molecules, the spacecraft took aid from Imaging infrared spectrometer (IIRS). The discovery is being hailed as significant for future planetary explorations & future projects on earth’s lunar surface.
IIRS: Collecting evidence for future endeavours
The data about the presence of hydroxyl and water have been obtained by the homegrown instrument, imaging infrared spectrometer (IIRS) aboard Chandrayaan-2. It is an imaging instrument that collects information from the Moon’s electromagnetic spectrum to understand the mineral composition, as well as undertakes volatile mapping of the Moon. This is the first for IIRS capabilities on India’s second lunar mission to operate in the spectral range of 0.8 to 5 µm (micrometre), at the high resolution of 20 nm (nanometre), which enhances the ability for precisely distinguishing between OH (hydroxyl) and H20 (Water molecules). This instrument was developed by the Ahmedabad based unit of Space Applications Centre (SAC) of ISRO.
Moon Mineralogy Mapper (M3)
This is not the first time India’s lunar mission has made such a discovery. A decade ago, India’s maiden lunar mission, Chandrayaan-1 was launched. It had carried a similar instrument named Moon Mineralogy Mapper (or M3) for collecting and detecting surface water on the lunar surface. However, the range of detection was between 0.4 to 3 micrometre. It was developed by NASA’s Jet Propulsion Laboratory and was not indigenous to ISRO. But now, ISRO’s IIRS, which has a higher wavelength and spectral range, permits better accuracy in results.
According to the research published in the Current Science, the initial data analysis from IIRS demonstrates the presence of widespread lunar hydration and unambiguous detection of OH and H2O signatures on the Moon between 29 degrees north and 62 degrees north latitude. Along with this, researchers also observed that the sunlit regions at higher latitudes of the Moon were found to have higher hydroxyl or water molecules.
The scientists at the Indian Institute of Remote Sensing (IIRS) in Dehradun reckon that the formation of hydroxyl and water molecules on the lunar surface is due to a concept known as ‘Space Weathering,’ which is a process of interaction of solar winds with that of the lunar surface. This blended with impact events led to chemical changes that further triggered the formation of reactive hydroxyl molecules. According to the researchers, the precise interpretation of hydration features is crucial as it provides significant inputs regarding the geology, geophysics of the mantle in terms of their mineralogy, chemical composition, rheology and solar-wind interaction.
The important highlight of the research is that the new discovery is hailed as crucial for future planetary exploration for resource utilisation. It will serve as an area of interest for countries rushing to the Moon with future plans to build lunar bases. Also, the presence of these water molecules and other elements provides an opportunity to piece the puzzle of the mystery – tracing back the origin and evolution.