Scientists now know the final destination for NASA's water-seeking lunar impact probe, an eternally-dark depression called Cabeus A near the moon's south pole believed to harbor hidden ice.

A map of the lunar south pole with Cabeus A labeled near the bottom center. Credit: NASA

The Lunar Crater Observation and Sensing Satellite will spend the next four weeks tweaking the trajectory of its attached Centaur rocket to line up its high-speed collision with the moon.

The impact will occur around 7:30 a.m. EDT on Oct. 9 (1130 GMT; 4:30 a.m. PDT), less than 10 hours after the Centaur is released and the sensor-laden shepherding spacecraft backs away to a separation of about 10 minutes.

The shepherding satellite, which actively controlled the 47-foot-long stack during the cruise, will monitor Centaur's plunge into the moon with a suite of nine science payloads beaming live data back to Earth.

The sensors will provide an close-up view of the explosive impact and the 350 metric tons of rock excavated from the cosmic collision as the spacecraft flies through the debris cloud. Scientists hope to find the tell-tale chemical signature of water ice.

Officials wanted to ensure the debris plume would be illuminated by the sun, providing the best possible viewing conditions for astronomers. High concentrations of hydrogen, a flat crater floor, gentle slopes and a lack of boulders were other considerations that led to the choice of Cabeus A, according to NASA.

Previous lunar missions have found evidence of hydrogen deep inside polar craters that never see sunlight. LCROSS is the first mission dedicated to confirming the suspected water's existence.

The Lunar Reconnaissance Orbiter and the Hubble Space Telescope will also observe the debris cloud, as well as Earth-based telescopes in Hawaii, Arizona and New Mexico.

"These and several other telescopes participating in the LCROSS observation campaign will provide observations from different vantage points using different types of measurement techniques," said 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."

Despite losing roughly half of its maneuvering propellant in a software snafu last month, LCROSS has enough fuel to finish its mission, according to Dan Andrews, the mission's project manager at NASA's Ames Research Center in California.

When LCROSS and LRO launched in June, scientists had a short list of finalist craters near the lunar south pole.

The newest data collected by LRO, international lunar probes, and ground observatories allowed scientists to whittle down the list of about a half-dozen craters.

Ames hosted a science team meeting last month to give Tony Colaprete, the mission's principal investigator, input on the crater decision.

"The selection of Cabeus A was a result of a vigorous debate within the lunar science community that included review of the latest data from Earth-based observatories and our fellow lunar missions Kaguya, Chandrayaan 1, and the Lunar Reconnaissance Orbiter," Colaprete said.

During Friday's announcement, officials also said they are dedicating the mission to the memory of Walter Cronkite, the legendary television news anchor who passed away in July.