Chandrayaan-3 is all about showcasing India's ability to soft land on a celestial body. It is a complex mission and lessons have been learnt from the failure of the lander Vikram, which crash-landed on the moon during Chandrayaan-2. NDTV's former science editor Pallava Bagla explains the various phases of the long mission and what the ISRO has done to make sure that it does not face the same failure.