It might not be quite as exciting as life on Mars, but water on the moon is surely the next best thing. Nasa scientists yesterday announced that a probe that was deliberately crashed into the moon's southern polar region last month discovered at least 25 gallons of water.
"Yes, we found water," said Anthony Colaprete, a principal project investigator at Nasa's Ames research centre in California. "We didn't find just a little bit, we found a significant amount."
Scientists hailed the discovery as a success and finding water is a huge boost for future missions. Most believe the likeliest places for water are at the poles of the moon, where there are craters in permanent shadow.
Scientists hope future study of the probe's findings could shed light on the evolution of the solar system, in the same way as an ice core sample taken from deep beneath the earth's surface reveals data on ancient geological events.
The discovery of water is a result of preliminary analysis of data from the lunar crater observation and sensing satellite (Lcross). The probe and an accompanying rocket, Centaur, were deliberately crashed into the Cabeus crater near the moon's south pole and scientists have been studying the resulting plume of lunar dust for the past few weeks.
"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," said Michael Wargo, chief lunar scientist at Nasa's headquarters in Washington.
Lcross's spectrometer instrument examined light absorbed by the dust particles to determine their composition and discovered a chemical compound emitted when sunlight breaks up water molecules. The probe discovered an estimated 25 gallons of water, Colaprete said.
"We are ecstatic," said Colaprete. "Multiple lines of evidence show water was present in both the high-angle vapour 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."
But Robert Park, a physicist at the University of Maryland and prominent sceptic of manned space flight, said the discovery means "practically nothing" to future hopes of a base or colony on the lunar surface.
"They've haven't found a big reservoir of it," he said. "I suspect this is just water clinging to the soil particles. It's of almost no value at all. The amount of machinery you'd have to move up there to try to recover it – you'd have to do a lot before you could pay for the cost of that."
The Lcross and Centaur spacecraft launched in June and travelled nearly 5.6m miles before separating on the final approach to the moon. Nasa heavily promoted the mission, which occurred during celebrations of the 40th anniversary of the Apollo moon landing.
On 9 October as the craft neared the moon, Americans gathered on lawns and in parks overnight, awaiting a fireworks display. They were disappointed when the impact was invisible to the naked eye about 250,000 miles away.
The Nasa mission confirmed a previous discovery announced in September by an Indian space mission, Chandrayaan-1, which found small amounts of water in the lunar soil.