Spacecraft set to hit moon tomorrow

4:00AM Friday Oct 09, 2009

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• Video NASA prepares to fire projectile into the moon (1:03)
• Doc CRASH COURSE (714 KB)

WASHINGTON - Nasa will throw a one-two punch at the moon tomorrow morning and the world will have ringside seats for the lunar dust-up.

Nasa will send a used-up spacecraft slamming into the moon's south pole to kick up a massive plume of lunar dirt and then scan it to see if there's any water or ice spraying up.

The idea is to confirm the theory that water - a key resource if people are going to go back to the moon - is hidden below the barren moonscape.

The crashing spaceship was launched in June along with an orbiter that is mapping the lunar surface.

LCROSS - short for Lunar Crater Observation and Sensing Satellite - is on a collision course with the moon, attached to an empty 2.2-tonne rocket that helped get the probe off the ground.

Today, about 10 hours before smashing into the moon, LCROSS and its empty rocket will separate.

Then comes the first part of the lunar assault.

At 12.31am (NZT) the larger empty rocket will crash into a permanently dark crater and kick up a 10km high spray of debris.

Trailing just behind that rocket is the LCROSS satellite, beaming back to Earth live pictures of the impact and the debris plume using colour cameras.

It will scan for ice, fly through the cloud of debris and four minutes later take the fatal plunge itself, triggering a dust storm one-third the size of the first hit.

"This is going to be pretty cool," LCROSS project manager Dan Andrewssaid. "We'll be going right down into it. Seeing the moon come up at you is pretty spectacular."

Within an hour, scientists will know whether water was hiding there or not. The mission is a venture dreamed up by Nasa that has been working on a US$100 billion ($135 billion) programme to return astronauts to the moon.

The return-to-the-moon goal is being re-examined by Nasa and the White House.

These are not crashes for the faint of heart. The two ships will smash into the moon at 9000km/h, more than seven times the speed of sound.

The explosion will have the force of 1.5 tonnes of TNT and throw 350,000kg of lunar dirt out of the crater.

It will create a new crater - inside an old one - about half the size of an Olympic swimming pool, Andrews said.

But do not feel bad for the moon.

It gets crashes this size about four times a month from space rocks.

The difference is this one is planned and at just the right angle and location to provide interesting science for astronomers.

The crashes will be broadcast live on Nasa's website and the Hubble Space Telescope and other larger Earth telescopes will be trained at the moon.

The moon rises too late for the crash to be seen in New Zealand.