NASA plans to crash a space probe into the moon in 2009 — a collision so violent it will be visible on Earth through a telescope, the space agency said Monday.

The moon crash, part of a larger mission that includes a lunar orbiter, is a quest for ice. Water is the key ingredient for supporting future human outposts on the moon, a goal of the Bush administration.

NASA scientists say the collision should excavate a hole about a third the size of a football field and hurl a plume of debris into space.

After the crash of the space probe, the mothership that released it will fly through the plume and look for traces of water ice or vapor — similar to NASA's Deep Impact mission last July, which blasted into a comet.

The moon collision and orbiter will be the first of several lunar robotic projects before astronauts are sent to the moon, targeted for 2018. The entire mission will cost more than $600 million with the impactor project cost-capped at $80 million.

The mission is set to launch in October 2008, with a rocket that carries both the Lunar Reconnaissance Orbiter and impactor.

The orbiter will circle the moon for at least a year, mapping the surface, searching for water and scouting for potential future landing sites to send astronauts. The orbiter will pay particular attention to the south pole, which NASA considers a prime candidate for a future outpost.

The lunar spacecraft will target the south pole too, releasing its SUV-sized impactor probe in January 2009 on a suicide plunge at about 5,600 miles per hour toward a frozen crater believed to contain hidden ice.

If ice is found, it could be melted and the water used to help make rocket fuel or oxygen.

"These resources can make (a) future human return to the moon and future human occupation of the moon much more cost-effective," said Butler Hine, robotics deputy program manager at NASA's Ames Research Center in northern California which is developing the impactor.

In the 1990s, several robotic probes found elevated levels of hydrogen, a component of water, around the moon's poles, suggesting ice might lie beneath the frozen surface. But they failed to find vast expanses of it.

The 2008 mission won't be the first time NASA has crashed a robotic probe into the moon. In the 1960s, the space agency launched nine Ranger spacecraft on such a mission, but only three were successful, beaming back close-up pictures as they crashed.

The 1999 orbiting Lunar Prospector collided into the moon, but it was considered a disappointment because it failed to kick up a cloud of debris.