Astronomy Now Home





Target crater for LCROSS impacts revealed
DR EMILY BALDWIN
ASTRONOMY NOW

Posted: September 14, 2009


Bookmark and Share

NASA has selected a final destination for its Lunar Crater Observation and Sensing Satellite (LCROSS) which will impact the crater Cabeus A on 9 October.

LCROSS will search for water ice by sending its spent upper stage Centaur rocket to impact the permanently shadowed polar crater at the lunar south pole, while the satellite will fly through the plume of debris thrown up by the impact to measure its properties. After the first impact, and just four minutes later, the LCROSS satellite will too meet its fate in the crater, while the Moon-orbiting Lunar Reconnaissance Orbiter and Earth-based telescopes look on in the search for watery signatures. Shrouded in darkness for billions of years, this is the first time that such pristine material will be exposed to sunlight.

Close up of Cabeus A near the Moon's south pole. Image: NASA/JPL.

Cebeus A was selected from a number of craters based on a set of conditions that include good illumination conditions for observing the impact from Earth and an optimum 'landing' environment such as a flat crater floor, gentle slopes and the absence of large boulders.

“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,” says Anthony Colaprete, LCROSS project scientist and principle investigator at NASA’s Ames Research Center. “The team is looking forward to the impacts and the wealth of information this unique mission will produce.”

Ground based telescopes signed up to the observation campaign 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 will also tune in to the events as they unfold on the Moon.

“These and several other 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.”

The LCROSS mission will reach fruition on 9 October. Image: NASA.

Despite an incident last month where the LCROSS spacecraft inadvertently burnt up a large quantity of fuel, mission scientists are confident that the mission will still deliver.

“The LCROSS team has long been preparing for its final destination on the Moon, and we’re looking forward to October 9,” Andrews said. “The next 28 days will undoubtedly be very exciting.”

For more information about the LCROSS and LRO missions, see Astronomy Now's Moon Focus, on sale 17 September.