A picture of moon's surface taken from the lunar orbit by Chandrayaan-1's Terrain Mapping Camera. © ISRO

For all the criticism that India's maiden Moon mission Chandrayaan-1 faced after being bowled out in the early overs, one master stroke will ensure its name is etched forever in history textbooks — finding concrete evidence of water on the Moon's surface.

The Moon Mineralogy Mapper has emerged as the 'man of the match' for Chandrayaan-1 detecting wavelengths of reflected light that indicate a chemical bond between hydrogen and oxygen in materials on Moon's thin layer of upper soil.

M 3 , as the instrument is called, has confirmed existence of water on Moon by analysing the data collected from India's much-condemned lunar probe vehicle.

The finding gives a final stamp of approval to murmurs heard in NASA corridors 40 years ago, when rock samples brought back by Apollo astronauts were keenly analysed to look for water.

Now, fresh data from Chandrayaan-1, collected earlier this year but being ruthlessly re-analysed by ISRO and NASA scientists, give 'unambiguous' proof from spectral measurements made using infrared spectrometer. Planetary geologist Carle Pieters from Brown University, U.S., lead author of a paper1 that announces the find in Science, is quick to add that this is just a very thin film of water and not a puddle or lake. The water might be coming from within the Moon itself or from collision with a water bearing body like a comet or asteroid, according to the paper.

In fact three papers 1, 2, 3unveil date from three spacecraft — Chandrayaan-1, Cassini (1999) and Deep Impact (June 2009). The papers suggest that the lunar polar regions have greater chances of having water or hydroxyl than elsewhere.

As the Indian scientific community woke up hoping for an announcement to this effect today, India-born NASA geologist Amitabha Ghosh said this was a 'very interesting find' considering that it could be a good resource to tap oxygen and fuel from.

In Bangalore, Chadrayaan-1 project director Mylswamy Annadurai expressed satisfaction that one of the major objectives of the lunar probe had been met.

In a press conference, NASA revealed finer details of the agenda-setting find. "Water ice on the moon has been something of a holy grail for lunar scientists for a very long time," said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington. "This surprising finding has come about through the ingenuity, perseverance and international cooperation between NASA and the India Space Research Organization."

Chandrayaan-1 was launched on October 22, 2008 and terminated much ahead of its two year mission life on August 31, 2009, two days after ISRO lost radio contact with the craft.