Scientists have found "significant" amounts of water in a crater at the moon's south pole, a major discovery that will dramatically revise the characterization of the moon as a dead world and probably make it a more attractive destination for human space missions."The moon is alive," declared Anthony Colaprete, the chief scientist for the Lunar Crater Observation and Sensing Satellite mission.That mission, which on Oct. 9 used a rocket to punch a hole about 100 feet across in the moon's surface, then measured about 25 gallons of water in the form of vapor and ice. It could be evidence there is enough water in permanently shaded craters at the poles for future astronauts to live off the land. National Aeronautics and Space Administration plans -- under review by the Obama administration -- call for a return to the moon at the end of the next decade and construction of a lunar base where astronauts could live and work for months at a time. The presence of large quantities of water would make that plan more practical, because water could be used for drinking, to produce oxygen for breathing and even to make rocket fuel.A resource-rich moon also could serve as a low-gravity launching pad for missions to elsewhere in the solar system."This is painting a surprising new picture of the moon. This is not your father's moon," said Greg Delory, a space scientist at the University of California, Berkeley . He referred to the fact that, after the Apollo missions of the 1960s and '70s, the moon was regarded as a dead place with little to offer future explorers."What's really exciting is we've only hit one spot," said Peter Schultz, a geology professor at Brown University and a co-investigator on the mission. "It's kind of like when you're drilling for oil. Once you find it in one place, there's a greater chance you'll find more nearby."The $79 million lunar crater mission was launched in June to try to uncover the source of large quantities of hydrogen that had been measured by other spacecraft in lunar craters at the poles.
An artist's rendering of the probe approaching the Moon
"The argument that the moon is a dry, desolate place no longer holds water," says a press release from NASA. A Moon mission launched by the agency has confirmed the presence of water on the moon. The discovery comes a year after a NASA instrument on an Indian lander indicated there were water molecules on the surface of our satellite.

On September 24, 2008 the Indian Space Research Organisation had stated Chandrayaan-1 had discovered water based on readings from NASA's Moon Mineralogy Mapper, one of eleven instruments carried by the probe. Those results indicated water was widespread in low quantities. That probe, launched in October 2008, had to be abandoned on August 30 when contact was lost with it on the Moon's surface.

The new mission, called LCROSS, consisted of two separate spacecraft which travelled the 250,000 miles together in June before separating. An empty rocket slammed into the Cabeus crater, near the southern pole, while a small spacecraft stayed behind to take measurements from the plume of debris thrown up, although it too ultimately crashed into Cabeus. Across the United States people spent the night on lawns and in parks hoping to see the impact, on the 40th anniversary of the first Apollo Moon landing, but it was invisible to the naked eye. NASA had predicted a visible six-mile plume; the reality was only a mile high.

The twin impacts on October 9 are now known to have sent 25 gallons of water ice and vapour into the air amongst the debris kicked up from the 60 to 100 foot wide hole produced by the rocket. This amount only accounts for the debris scientists could actually see over the rim, and the remaining debris could contain more water. It is unclear how much water may be distributed accross the Moon, although hydrogen at the poles suggests water ice there. 

LCROSS stands for lunar crater observation and sensing satellite, which was the satellite's name, while its rocket companion was called Centaur. It took a month to analyse the spectrometer data from the mission, and efforts are ongoing to determine the composition of the remaining material kicked up out the crater. The whole project cost $75 million.

"We got more than just whiff. We practically tasted it with the impact," said project co-investigator Peter H Schultz. The material thrown up split into a curtain travelling sideways and a plume that passed the crater's rim, bringing it into the sunlight for the first time in billions of years. Both contained water. "We are ecstatic," said project leader Anthony Colaprete.
"We didn't find just a little bit, we found a significant amount."

Michael Wargo, who heads up lunar research for NASA, said "We're unlocking the mysteries of our nearest neighbour and by extension the solar system. It turns out the moon harbours many secrets, and LCROSS has added a new layer to our understanding." It is thought that by analysing the water we can learn of the moon's history, in a fashion similar to investigating Earth history with ice cores.

University of Maryland physicist Robert Park cautioned that people should not assume that water on the lunar surface would support a colony. "They've haven't found a big reservoir of it," he said. "I suspect this is just water clinging to the soil particles."

Buzz Aldrin, one of the first to walk on the Moon when he followed pioneer Neil Armstrong out of Apollo 11, said he was pleased by the news but added that "People will overreact to this news and say, 'Let's have a water rush to the moon.' It doesn't justify that." Aldrin wants the US to aim to colonise Mars, but NASA is looking at more lunar trips. Last month a new rocket was tested, and Barack Obama has set up a panel to look at possible Moon missions. George W. Bush had previously proposed a $100 billion programme to put more astronauts onto the Moon. NASA wants to return by 2020 and build a lunar base, allowing astronauts to remain for months at a time.