that came to a premature end on 28 August 2009. M3 was aimed at providing the first mineral map of the entire lunar surface. M3 data were reanalyzed years later and revealed "the most definitive proof to date" of the presence of water in shaded regions of craters near the Moon's north and south poles. Lunar scientists had discussed the possibility of water repositories for decades. They are now increasingly "confident that the decades-long debate is over" a report says. "The Moon, in fact, has water in all sorts of places; not just locked up in minerals, but scattered throughout the broken-up surface, and, potentially, in blocks or sheets of ice at depth." The results from the Chandrayaan mission are also "offering a wide array of watery signals." Lunar water production According to European Space Agency (ESA) scientists, the lunar regolith (a loose collection of irregular dust grains making up the Moon's surface) absorbs hydrogen nuclei from solar winds. Interaction between the hydrogen nuclei and oxygen present in the dust grains is expected to produce hydroxyl () and water (). The SARA (Sub keV Atom Reflecting Analyser) instrument developed by ESA and the Indian Space Research Organisation was designed and used to study the Moon's surface composition and solar-wind/surface interactions. SARA's results highlight a mystery: not every hydrogen nucleus is absorbed. One out of every five rebounds into space, combining to form an atom of hydrogen. Hydrogen shoots off at speeds of around and escapes without being deflected by the Moon's weak gravity. This knowledge provides timely advice for scientists who are readying ESA's BepiColombo mission to Mercury, as that spacecraft will carry two instruments similar to SARA. Lunar caves Chandrayaan-1 imaged a lunar rille, formed by an ancient lunar lava flow, with an uncollapsed segment indicating the presence of a lunar lava tube, a type of large cave below the lunar surface. The tunnel, which was discovered near the lunar equator, is an empty volcanic tube, measuring about in length and in width. According to A. S. Arya, scientist SF of Ahmedabad-based Space Application Centre (SAC), this could be a potential site for human settlement on the Moon. Earlier, Japanese Lunar orbiter SELENE (Kaguya) also recorded evidence for other caves on the Moon. Tectonism Data from the microwave sensor (Mini-SAR) of Chandrayaan-1 processed using the image analysis software ENVI, has revealed a good amount of past tectonic activity on