The IIRS captures data from the lunar surface’s electromagnetic spectrum, which is then utilised to determine mineral composition.
According to a new report published in Current Science, an instrument on the Indian Space Research Organisation’s Chandrayaan-2 has found the existence of hydroxyl (OH) and water molecules (H2O) on the Moon’s surface.
The data was acquired from the electromagnetic spectrum received from the lunar surface by the Imaging infrared spectrometer (IIRS), created by ISRO’s Space Applications Centre (SAC) in Ahmedabad, and then utilised to detect mineral composition. The lander and rover on Chandrayaan-2, which was launched in 2019, were entirely destroyed in a sad crash, but the orbiter remained operational and is now being used by scientists to make ground-breaking findings from the lunar surface.
The instrument has a wavelength range of 0.8 to 5 micrometres, allowing it to discriminate between OH (hydroxyl) and H2O (water) molecules with greater precision. The Moon Mineralogy Mapper or M3 was also used by Chandrayaan-1 in 2008. Its wavelength, however, was limited to 0.4 to 3 micrometres. Scientists questioned the instrument’s accuracy at the time, claiming that it was difficult to discern OH from H2O in this situation.
The paper, co-authored by scientists from the IIRS in Dehradun, the SAC in Ahmedabad, the UR Rao Satellite Centre, and the ISRO headquarters in Bengaluru, reveals that the formation of hydroxyl or water molecules occurs as a result of a process known as space weathering, which occurs when solar winds blow over the lunar surface. Another factor could be the interaction of small meteorites with the surface, which could cause chemical changes.
The discovery is also important for future planetary exploration and resource utilisation, according to the research. “The appropriate interpretation of hydration features using spectrum analysis is vital because it gives important inputs into the geology and geophysics of the mantle (of the moon) in terms of mineralogy, chemical composition, rheology, and solar–wind interaction.”