Friday, September 11, 2009

NASA selects lunar crater for October collision

NASA has picked the lunar crater it wants to whack next month with a rocket stage and spacecraft that launched this summer from Cape Canaveral.

The winner: Cabeus A, a relatively flat, 60-mile wide crater on the moon's south pole that may hold water ice in its permanently shadowed top soil.

NASA launched the Lunar Crater Observation and Sensing Satellite, or LCROSS, June 18 on a United Launch Alliance Atlas V rocket.

A secondary payload to the Lunar Reconnaissance Orbiter now circling the moon, the spacecraft has been hauling the rocket's Centaur upper stage around Earth while lining up for an Oct 9 impact.

The Centaur will separate and begin hurtling toward a first collision with Cabeus A at 7:30 a.m. EDT.

LCROSS will fly through the plume of regolith kicked up by the flattened rocket stage, analyzing it with sensors, before crashing four minutes later.

Telescopes in space and on the ground will also observe the impacts, which will be visible west of the Mississippi because of the timing just after daybreak in the east.

The spacecraft is searching for evidence of water ice, the possibility of which was suggested by Lunar Prospector's discovery of hydrogen in permanently shadowed craters in the late 90s.

The water could serve as a resource for use by astronaut explorers, or simply improve understanding about the solar system's history.

"From a scientific standpoint, this is incredibly important," said Anthony Colaprete, LCROSS principal investigator. "It's a time capsule, it's a window into the past of the entire inner solar system, of Earth."

Mission managers said the spacecraft will be able to complete all its objectives despite a failure several weeks ago that caused it to burn too much fuel for a period of time.

The precise targeting of a "sweet spot" in Cabeus A will continue until impact day.

IMAGE NOTE: Click the images twice to fully enlarge them. Above, a picture showing a group of finalists considered for impact by LCROSS and it's Centaur rocket stage. The crater left of center highlighted with the marker "SP_C" is the chosen target. Below, an artist's rendering of the Centaur separating from LCROSS. Credits: NASA.

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