How ISRO zeroed in on Chandrayaan's final landing site

In a landmark event, India's third lunar endeavor, Chandrayaan-3, is poised to achieve a historic milestone by making a first successful landing on the southern polar region of the Moon. Amidst this anticipation, Indian Space Research Organisation's (ISRO) scientists at Space Applications Centre (Isro-SAC) and the Physical Research Laboratory (PRL) reflect on how the landing site was choosen for Chandrayaan-3.

The best landing site of Chandrayaan-3 was meticulously pikced through an exhaustive analysis of diverse datasets gathered from prior lunar missions, including Chandrayaan-1, Chandrayaan-2, Selene, and the Lunar Reconnaissance Orbiter (LRO) mission led by the US.

The parameters for selection included a thorough assessment of the lunar topography, slope characteristics, illumination patterns, and potential hazards. Collaborative efforts from a team comprising scientists from Isro and allied institutions harnessed an innovative moving window technique to identify regions spanning 4 km x 2.4 kmwithin the latitude bracket of 60° to 70° south on the Moon's near side that presented minimal risks.


This intricate process resulted in the identification of 20 potential sites, each earmarked for further in-depth analysis. Medium-resolution data gleaned from the Lunar Orbiter Laser Altimeter (LOLA) of the US LRO, coupled with data from Selene and the LRO's Narrow Angle Cameras (NACs), played a pivotal role in this refinement phase. From this pool, eight sites emerged as the prime candidates for meticulous examination, leveraging high-resolution data obtained from the Orbiter High-Resolution Camera (OHRC) aboard Chandrayaan-2.

The OHRC captured stereo images of these eight selected sites at an astonishing pixel resolution surpassing 32 centimeters. These images, in turn, facilitated the creation of a digital elevation model that lent valuable insights into the terrain's characteristics. This landmark accomplishment was realized through the dedicated efforts of a group of scientists comprising Amitabh, K Suresh, Ajay K Prashar, and Abdullah Suhail, affiliated with the High-Resolution Data Processing Division.