NASA will tomorrow launch a spectacular mission to bomb the Moon. Their LCROSS mission will blast off from Cape Canaveral, Florida, carrying a missile that will blast a hole in the lunar surface at twice the speed of a bullet.

The missile, a Centaur rocket, will be steered by a shepherding spacecraft that will guide it towards its target - a crater close to the Moon's south pole.

Scientists expect the blast to be so powerful that a huge plume of debris will be ejected.

The attack on the Moon is not a declaration of war or act of wanton vandalism. Space scientists want to see if any water ice or vapour is revealed in the cloud of debris.

Though the Moon mostly a dry airless desert, they believe ice could be trapped in crater shadows near the south pole which never receive any sunlight. If so it could provide vital supplies for a manned moonbase.

Last year, British scientists identified regions where water might be found on the Moon and estimated that there could be enough to fill one of Europe's largest reservoirs.

The spacecraft will not head straight for the Moon. First it will orbit the Earth a number of times while its precise target is identified. Finally, it will send the missile into the Moon at twice the speed of a bullet on October 8.

The shepherding spacecraft will follow close behind, taking pictures and analysing the ejected debris as it looks for evidence of water. It has just four minutes to do this before it crashes into the Moon itself, producing a spectacular explosion that should be visible in amateur astronomers' telescopes.

It is a busy time for Moon crashes. Last week Japan's Kaguya probe collided with the Moon at the end of its own mission.

The LCROSS mission - it stands for Lunar CRater Observation and Sensing Satellite - will launch on an Atlas V rocket together with another spacecraft, called the Lunar Reconnaissance Orbiter.

The orbiter will circle the Moon for at least a year searching for potential landing sites for astronauts when they return there in the next decade. It will also look for suitable materials that might support a colony.

The dual mission was due to blast off today but was delayed to make way for the shuttle Endeavour. However, another hydrogen leak means that the shuttle launch has now been delayed until next month.