ISRO's Chandrayaan-2 detects presence of water ice at permanently shadowed regions of moon

ISRO's second Moon mission, Chandrayaan-2 has detected the presence of water ice on the Moon, data obtained from the mission revealed on Tuesday, the second day of a two-day lunar science workshop. One of the eight payloads of Chandrayaan-2 detected an unambiguous presence of water ice at the permanently shadowed regions of the Moon.

The initial data analysis from imaging infrared spectrometre (IIRS) clearly demonstrates the presence of widespread lunar hydration and unambiguous detection of water on the Moon. Former Indian Space Research Organisation (ISRO) Chairman A S Kiran Kumar has co-authored the paper which was published in the Current Science journal.

Imaging infrared spectrometre (IIRS) is one of the payloads on-board Chandrayaan-2. It is placed in a 100 km polar orbit to acquire global scientific data.

Plagioclase-rich rocks have been found to have higher OH (hydroxyl) or possibly H2O (water) molecules when compared to the mare regions, which were found to have more dominance of OH at higher surface temperature, the report said.

The development also assumes significance considering that Chandrayaan-2 did not yield desired results. Permanently shadowed regions (PSR) have largely remained inaccessible as no sunlight reaches these regions, making it difficult to get images.

What ISRO chairperson K Sivan said

Earlier studies using hybrid-polarimetric SAR data led to ambiguous detection of water ice regions as it had similar sensitivity to surface roughness and water ice.

Full polarimetric DFSAR, which uses measurements of electrical properties of materials, can decouple the effect of water ice and surface roughness.

Potential patches of 'dirty ice' within the Cabeaus crater on the lunar south pole, were also detected by the radar instrument.

Patchy dirty ice involves ice crystals mixed with the lunar regolith, unlike continuous sheets of ice.

Regolith is the top surface of the moon extending up to three to four metres, consisting of loose deposits.

The ability to combine polarimetric radar images from two wavelengths has also brought forth subsurface features.

The polarimetric data helps in identifying the distribution of impact melts.