The Franklin Files

A "significant amount" of frozen water has been found on the moon, says the US space agency.

The discovery heralds a major leap forward in space exploration and boosts hopes of a permanent lunar base.

Preliminary data from a moon probe "indicates the mission successfully uncovered water in a permanently shadowed lunar crater", NASA said in a statement on Friday.

"The discovery opens a new chapter in our understanding of the moon."

The data was found after NASA sent two spacecraft crashing into the lunar service last month in a dramatic experiment to probe Earth's nearest neighbour for water.

One rocket slammed into the Cabeus crater, near the lunar southern pole, at around 9000 km/h.

The impact sent a huge 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.

"We are ecstatic," said Anthony Colaprete, project scientist and principal investigator for the $US72.87 million ($A79 million) LCROSS mission.

"Multiple lines of evidence show water was present in both the high angle vapor plume and the ejecta curtain created by the LCROSS Centaur impact.

"The concentration and distribution of water and other substances requires further analysis, but it is safe to say Cabeus holds water."

Scientists had previously theorised that, except for the possibility of ice at the bottom of craters, the moon was totally dry.

Finding water on Earth's natural satellite is a major breakthrough in space exploration.

"We're unlocking the mysteries of our nearest neighbour and, by extension, the solar system," said Michael Wargo, chief lunar scientist at NASA headquarters in Washington.

But Colaprete cautioned the full understanding of the LCROSS data could take some time.

"The data is that rich," he said.

"Along with the water in Cabeus, there are hints of other intriguing substances.

"The permanently shadowed regions of the moon are truly cold traps, collecting and preserving material over billions of years."

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 US President Barack Obama said existing budgets are not large enough to fund a return mission before 2020.

[link to news.ninemsn.com.au