Chandrayaan's Vajpayee connection: When former PM Atal Bihari Vajpayee changed name of India's Moon mission Chandrayaan-3: ISRO's Chandrayaan-3 mission is set to attempt a moon landing today, aiming to explore the lunar south pole for water ice. Former Prime Minister Atal Bihari Vajpayee renamed the mission from ‘Somayaan’ to ‘Chandrayaan.’