Ahead of the expected touchdown of Chandrayaan-3 mission's lander module on the surface of the Moon on Wednesday, former ISRO Chairman G Madhavan Nair kept his fingers crossed and said it is a very complex manoeuvre and one has to be cautious as all systems have to work in unison for its success.

Nair, who headed the space agency when Chandrayaan-1 mission was launched in 2008, said a successful landing would herald a big beginning for ISRO's next phase of planetary exploration.

"It's a very complex manoeuvre. We narrowly missed it (soft landing on the Moon in Chandrayaan-2 mission) in the last two kms (above the lunar surface)," he told PTI on Monday.

"So there are a host of things that have to work in unison....thrusters, sensors, altimeters, computer software and all those things. Any glitch happening anywhere...we can be in trouble," Nair said.

"We have to be really cautious and watch. Of course, I understand that ISRO has done enough simulations and also redundancies have been built in so that chances of such failure are remote. Still, we have to keep our fingers crossed," he added.

According to ISRO, the lander module with the rover in its belly is expected to touch down on the Lunar surface around 6.04 pm on Wednesday.

Nair said: "Data we may collect from the (lunar) surface will be useful in identifying some minerals...rare minerals, if at all, helium-3 and so on. Also try to have some investigations as to what type of set up we can have near the lunar south pole either for exploration or human presence. It (successful soft-landing) is going to be a big beginning for ISRO's next phase of planetary exploration".

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