Putting Chandrayaan-2 into the Earth orbit on July 22 was the easiest bit, tougher challenges await this most complex mission. ISRO Chairman Dr K Sivan, speaking exclusively to NDTV'S Science Editor Pallava Bagla, said soft landing on the moon will be the most terrifying 15 minutes for ISRO since India has no experience of soft landing on another planetary body. The Vikram Lander is expected to soft land on the South Pole region of the moon in first week of September.