Among the many accomplishments of Chandrayaan-1, its biggest discovery perhaps was to find hydroxyl and water molecules on the lunar surface.

• Glimpse at the history of Chandrayaan-1: Chandrayaan-1 was India’s first mission to moon, which was launched by Polar Satellite launch Vehicle, PSLV-C11 on October 22, 2008, from Sriharikota. Chandrayaan-1 made more than 3,400 orbits around the moon. It was operational for 312 days till August 29, 2009. The lift-off mass of Chandrayaan-1 was 1380 kg, according to ISRO.
• Chandrayaan-1 key achievements: The Chandrayaan-1 discovered traces of water on the moon-a path-breaking discovery in the world of space science. Chandrayaan-1 also discovered water ice in the North Polar Region of the Moon. It also detected Magnesium, Aluminium and Silicon on the lunar surface. Global imaging of the moon is another achievement of this mission.
• Scientific instruments on-board Chandrayaan-1: There were eleven scientific instruments onboard Chandrayaan-1 spacecraft. Five of them were Indian and other six were from ESA (3), NASA (2) and Bulgarian Academy of Sciences (1) selected through ISRO Announcement of Opportunity (AO). Two of the ESA instruments had Indian collaboration.

Difference between Chandrayaan-1 and Chandrayaan-2