Washington, Sep 25 - The confirmation of elevated water molecules in the moon's polar regions by India's maiden lunar mission Chandrayaan-1 raises new questions about its origin and effect on the mineralogy of the moon, US scientists say.

'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 Indian Space Research Organization (ISRO).'

NASA's Moon Mineralogy Mapper, or M3, instrument reported the observations. M3 was carried into space on Oct. 22, 2008, aboard the ISRO's Chandrayaan-1 spacecraft.

From its perch in lunar orbit, M3's state-of-the-art spectrometer measured light reflecting off the moon's surface at infrared wavelengths, splitting the spectral colours of the lunar surface into small enough bits to reveal a new level of detail in surface composition.

When the M3 science team analysed data from the instrument, they found the wavelengths of light being absorbed were consistent with the absorption patterns for water molecules and hydroxyl.

'For silicate bodies, such features are typically attributed to water and hydroxyl-bearing materials,' said Carle Pieters, M3's principal investigator from Brown University, Providence.

'When we say 'water on the moon,' we are not talking about lakes, oceans or even puddles. Water on the moon means molecules of water and hydroxyl that interact with molecules of rock and dust specifically in the top millimetres of the moon's surface.

The M3 team found water molecules and hydroxyl at diverse areas of the sunlit region of the moon's surface, but the water signature appeared stronger at the moon's higher latitudes.