Why Moon’s south pole? ISRO chief explains Chandrayaan-3 landing site choice

India created history on Wednesday (August 23) by becoming the first nation to land a spacecraft on the lunar south pole, or the dark side of the Moon.

Several other countries were in the race to the Moon’s dark side, too. Only on August 20, the Russian Luna-25 crash-landed on the Moon’s south pole. Before that, Israel and Japan have failed as well. And, of course, in 2019, Chandrayaan-2 met with the same fate in the eleventh hour.

So, what is so significant about the lunar south pole that ISRO chose to soft-land the Chandrayaan-3 module there?

The ultimate aim

A day after the successfully soft-landing, ISRO chief S Somanath explained to news agency ANI why the Moon’s south pole is so important for scientists.

“The south pole has a specific advantage with respect to being less illuminated by the Sun. There is a potential to have more scientific content in terms of retention of water below the subsurface and also because of elemental composition and other activities,” Somanath explained in the interview.

“Scientists who are working on the Moon showed a lot of interest in the south pole because ultimately human beings want to go and create colonies and then travel beyond. So, the best place is something we are looking form and the south pole has the potential to be that,” he added.

The difficult south pole

Previous unmanned Moon missions and the crewed Apollo landings had targeted the relatively wide and flat expanses of the equatorial region. But the south pole is full of craters and boulders, which is what makes a soft-landing incredibly difficult.

Somanath, in an interview to NDTV, too, said the “huge amount of scientific possibilities on the south pole…are related to the presence of water and minerals on the moon.”

One of the major targets of the Chandrayaan-3 mission is to advance human knowledge of lunar ice, which could be among the Moon’s most valuable resources, he told NDTV. He added that five of the instruments on board the Vikram lander are for exploring other “physical processes” on the Moon.

14 crucial days

“Pragyan rover has two instruments. Both are related to elemental composition findings on the moon as well as chemical compositions...Moreover, it will do the roving over the surface. We will also do a robotic path-planning exercise, which is important for future explorations for us,” Somanath told ANI.

Over the next 14 days, which is equivalent to one lunar day, the six-wheeled Pragyan rover will explore the lunar surface and carry out experiments. Both Vikram and Pragyan have a mission life of one lunar day.

Somanath also told NDTV says that since Chandrayaan-2 made a hard landing (crashed), nothing could be recovered for Chandrayaan-3 and everything had to be created afresh. He added that ISRO spent the first year figuring out what went wrong with Chandrayaan-2 and the next revising everything. The past two years were spent on conducting tests. Also, COVID upset some of the plans.

Among the ISRO’s upcoming missions are the Aditya mission to the Sun and Gaganyaan. “Aditya mission is getting ready for launch in September, while Gaganyaan is still a work in progress,” Somanath told ANI.

“We will do a mission possibly by the end of September or October to demonstrate the crew module and crew escape capability, which will be followed by many test missions until we do the first manned mission possibly by 2025,” he said about Gaganyaan.