A new chapter in space exploration has been opened up after Nasa confirmed that their mission to bomb the Moon had found "significant quantities" of frozen water.
Scientists said the "exciting" findings had gone "beyond expectations" as fully formed ice was found in a crater on the planet.
They said that the ice – thought to be in granules mixed with grains of Moon dust – heralded a major leap forward in space exploration and boosted hopes of a permanent lunar base.
The water was found in one mile high plume of debris that was kicked up by the Lunar Crater Observation and Sensing Satellite (LCROSS) last month when it crashed into the Cabeus crater near the Moon's south pole.
"We are ecstatic," said Anthony Colaprete, project scientist and principal investigator for the £49 million space mission.
"Indeed, yes, we found water. And we didn't find just a little bit, we found a significant amount."
He said in a "eureka moment" analysis of the plume of debris sprayed up by a 30 ft crater showed the equivalent of "a dozen two-gallon buckets" of water was thrown up by the impact.
"This is a great day for science and exploration," said Doug Cooke, associate administrator of LCROSS. "The remarkable results have gone beyond our expectations. It is incredibly exciting."
The identification of water-ice in the impact plume is important for purely scientific reasons, but also because a supply of water on the Moon would be a vital resource for future human exploration.
The findings, which completely contradict previous beliefs that the Moon was a dry arid place, justify the controversial mission.
It also reignites mankind's dreams of colonising Earth's only satellite.
"We're unlocking the mysteries of our nearest neighbour and, by extension, the Solar System," said Michael Wargo, chief lunar scientist at Nasa's headquarters in Washington DC.
The mission took place on 9th October and was watched by millions across the globe live on the internet.
One rocket slammed into the Cabeus crater, near the lunar southern pole, at around 5,600 miles (9,000 kilometres) per hour.
The impact sent a plume of material billowing up from the bottom of the crater, which has not seen sunlight for billions of years.
The rocket was followed four minutes later by a spacecraft equipped with cameras to record the impact. At the time the crash seemed to be disappointing as the "plume of debris" was not visible to Earth based satellites.
However analysis of the huge amount of data the spacecraft collected and from satellite's spectrometers provided definitive evidence about the presence of water.
A spectrometer examines light reflected from a substance and is able to identify their composition.
Over the last decade, scientists have found some hints of underground ice on the moon's poles, mainly in the form of compounds of hydrogen but this is the best evidence yet.
The discovery is expected to have major implications for the future of lunar exploration, and a ready supply of water could help set up lunar bases or launch missions to Mars.
Mr Colaprete said that it should be possible to purify the water for drinking even though it appeared to mixed with poisonous methanol.
Only 12 men, all Americans, have ever walked on the Moon, and the last to set foot there were in 1972, at the end of the Apollo missions.
But Nasa's ambitious plans to put US astronauts back on the moon by 2020 to establish manned lunar bases for further exploration to Mars under the Constellation project are increasingly in doubt.
Nasa's budget is currently too small to pay for Constellation's Orion capsule, a more advanced and spacious version of the Apollo lunar module, as well as the Ares I and Ares V launchers needed to put the craft in orbit.
A key review panel appointed by President Barack Obama said existing budgets are not large enough to fund a return mission before 2020.
As well as a possible site for a base, the permanently shadowed regions could hold a key to the history and evolution of the solar system, much as an ice core sample taken on Earth reveals ancient data. In addition, water, and other compounds represent potential resources that could sustain future lunar exploration.
