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NASA Selects Target Crater for Lunar Impact

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Sept. 11, 2009: NASA's Lunar Crater Observation and Sensing Satellite (LCROSS) is racing toward a double-impact on the moon at 7:30 am EDT on Oct. 9th. Today NASA announced exactly where the crash will take place.

The target crater is Cabeus A. It was selected after an extensive review of the best places to excavate frozen water at the lunar south pole.

Above: Craters of interest around the lunar south pole. LCROSS is targeting Cabeus A. Image credit: NMSU/MSFC Tortugas Observatory.

"The selection of Cabeus A was a result of a vigorous debate within the lunar science community. We reviewed the latest data from Earth-based observatories and our fellow lunar missions Kaguya, Chandrayaan-1, and the Lunar Reconnaissance Orbiter," says Anthony Colaprete, LCROSS project scientist and principle investigator at NASA's Ames Research Center. "The team is looking forward to wealth of information this unique mission will produce."

LCROSS will search for ice by plunging its spent upper-stage Centaur rocket into the permanent shadows of Cabeus A, where water might be trapped in frozen form. The LCROSS satellite will then fly into the plume of debris kicked up by the impact and measure the properties of the plume before it also collides with the lunar surface.

The LCROSS team selected Cabeus A based on a set of conditions that includes favorable illumination of the debris plume for visibility from Earth, where astronomers will be watching closely. Cabeus A also has a high concentration of hydrogen (a constituent of water, H2O) and favorable terrain such as a flat floor, gentle slopes and the absence of large boulders.

Professional astronomers will use many of Earth's most capable observatories to monitor the impacts. These observatories include the Infrared Telescope Facility and Keck telescope in Hawaii; the Magdalena Ridge and Apache Ridge Observatories in New Mexico and the MMT Observatory in Arizona; the newly refurbished Hubble Space Telescope; and the Lunar Reconnaissance Orbiter, among others.

Amateur astronomers can monitor the impact, too. Observing tips may be found here.

"Telescopes participating in the LCROSS Observation Campaign will provide observations from different vantage points using different types of measurement techniques," says Jennifer Heldmann, lead for the LCROSS Observation Campaign at Ames. "These multiple observations will complement the LCROSS spacecraft data to help determine whether or not water ice exists in Cabeus A."

During a media briefing Sept. 11, Daniel Andrews, LCROSS project manager at Ames, provided a mission status update: The spacecraft is healthy and has enough fuel to successfully accomplish all mission objectives. Andrews also announced the dedication of the LCROSS mission to the memory of legendary news anchor, Walter Cronkite, who provided coverage of NASA's missions from the beginning of America's manned space program to the age of the space shuttle.

Right: The LCROSS mission has been dedicated to the memory of Walter Cronkite, who covered NASA missions from Mercury through the space shuttle. Image credit: CBS News. [more]

"Dad would sure be proud to be part, if just in name, of getting humans back up to the moon and beyond," says Chip Cronkite, son of the famed news anchor.

"We're looking forward to October 9th," Andrews says. "The next 28 days will undoubtedly be very exciting."

Cabeus A, here we come!

Editor: Dr. Tony Phillips | Credit: Science@NASA

more information

Moonship photographed by Backyard Astronomers -- (Science@NASA)

LCROSS Home Page -- (NASA/HQ)

LCROSS Mission Page -- (NASA/Ames)

The LCROSS mission was selected in April 2006 as a mission manifested with the Lunar Reconnaissance Orbiter. Both missions launched on June 18, 2009 on an Atlas V from Cape Canaveral, Fla. The LCROSS mission and science operations are managed at Ames.

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