WASHINGTON — The United States successfully blasted a rocket into the moon on Friday, slamming it into a crater near the lunar south pole in a bid to discover water, US space agency NASA said.

No light flash was visible in the thermal images broadcast on NASA television, as the 2.3-tonne rocket impacted the Cabeus crater at 1131 GMT, 7:31 a.m. ET.

A second shepherding spacecraft flew through the debris plume, collecting and relaying key data back to Earth before it too plowed into the lunar surface, according to the US space agency.

The LCROSS mission is hoping to uncover whether there is water or ice below the moon’s surface that could be used by astronauts on future space missions.

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WASHINGTON — NASA would make an explosive return to the moon Friday when it sends a satellite and a rocket booster crashing into a lunar crater to look for water.

Conspiracy theories aside — a Do Not Bomb the Moon website has been campaigning against the move — there is no actual bomb, but the US space agency’s unmanned LCROSS satellite and heavier Centaur upper-stage rocket will still leave huge impacts where NASA hopes to find evidence of water or ice.

At 7:30 a.m. Eastern Time, the rocket and four minutes later the "shepherding spacecraft" will slam into the Cabeus crater floor near the moon’s south pole at 9,000 km/h to kick up a plume of lunar dirt to an altitude of about 10 kilometres.

The flash that follows the impact will last about 30 seconds.

Cameras mounted on the 891-kilogram shepherding spacecraft will beam live footage of the initial impact as the craft flies through the debris plume, collecting and relaying key data back to Earth before it too plow’s into the moon.

The Lunar Crater Observation and Sensing Satellite (LCROSS) separated from the Centaur rocket at early Friday in preparation for the pair of impacts.

"We don’t anticipate anything about presence or absence of water immediately. It’s going to take us some time," cautioned Anthony Colaprete, project scientist and principal investigator for the 79-million-dollar LCROSS mission, which is also the first preparatory mission of the Constellation program that aims to send Americans back to the moon by 2020.

Colaprete projected it would take several days for analysts to evaluate the data and several weeks to determine whether and how much hydrogen-bearing compounds were found.

For those hoping to catch a bare-eyed glimpse of the impact, the scientist had sad news.

"It’s not going to be a grand spectacle that you can go outside in your back yard and see with your bare eyes or even a good binoculars. It’s going to be too faint," said Colaprete.

More powerful telescopes around the world and also the Hubble Space Telescope will nevertheless get a good view as they focus on the giant cloud of debris.

NASA scientists will be looking at what spews out after 350 tonnes of debris is ejected from the cold, dark Cabeus crater, staking its hopes on water in the form of ice.

The crater is 100 kilometres across and between 2.5 to four kilometres deep.

"We’re hunting for how water ice was stored and trapped in these permanently shadowed areas over billions of years and we want to find out how much there is," explained Peter Schultz, a professor of geological sciences at Brown University who helped design the mission.

The mission comes just two weeks after India hailed the discovery of water on the moon with its Chandrayaan-1 satellite mission in partnership with NASA.

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

Finding water on Earth’s natural satellite would be a major breakthrough in space exploration and pave the way toward future lunar bases for drinking water or fuel, or even man living on another planet.

"This could be the place that we could go to mine water for a permanent lunar base," said Schultz.

"It tells us something about how water was delivered to the moon and other planets in a sort of cosmic rain, meaning impacts from comets over eons."

But much uncertainty surrounds NASA’s future dealings with the moon, as a key review panel appointed by President Barack Obama’s administration said existing budgets bar a return to the cold outpost before 2020.