NASA Finds Water on the Moon

“We found water.” Anthony Colaprete, project scientist for NASA’s Lunar Crater Observing and Sensing Satellite (LCROSS) mission, announced the news at a press conference today at NASA’s Ames Research Center.

On October 9, 2009, LCROSS and its empty rocket stage impacted the Cabeaus crater at the Moon’s South Pole. The rocket stage hit first, creating an ejecta plume that was studied by instruments on LCROSS before it also impacted the surface. Several other spacecraft and Earth-based observatories were also trained on the plume. Scientists had theorized that water might exist in permanently shadowed craters at the lunar poles. LCROSS’s preliminary findings confirming the theory were announced just one month after the impact. At that time, project scientists had explained to impatient reporters that they needed more than three hours to collect and analyze the data.

According to Colaprete, the data suggest more significant amounts of water – in vapor and ice form – than expected: several “buckets-worth” instead of tablespoons. Today’s results were based on observations of the 10-12 kilometer diameter plume by a near-infrared spectrometer and an ultraviolet visible spectrometer that measured the wavelengths produced by different compounds in the plume. Several indicators – including hydroxyl signatures produced when water vapor comes in contact with sunlight – confirmed the presence of water as well as other substances.

Greg Delory, senior fellow of the Space Sciences Laboratory and Center for Integrative Planetary Sciences at the University of California at Berkley, provided context for these findings. He said that the lunar poles serve as “record keepers” of the lunar and solar system history. LCROSS’ discovery helps answer a question that arose 10 years ago when large amounts of hydrogen were observed at the Moon’s South Pole and first suggested the presence of water. Those data were not definitive, however, spurring the quest to confirm the finding. Today’s results present a new set of questions about the source of the water. Delory identified three possible sources: comets, solar wind, or the Moon itself. These findings provide an “exciting…surprising new picture of the Moon,” he added.

Alluding to the disappointment that characterized the press conference on the day of the impact, Michael Wargo, chief lunar scientist for Exploration Systems at NASA Headquarters said “you were frustrated that day, we were frustrated that day,” but explained that scientists wanted to have confidence in their findings before making any announcements. Beyond the scientific potential of this finding in the “dusty attic of the solar system,” he added that this water could prove to be a resource for future exploration missions, and “the key to sustainability.”

Combining the data from LCROSS with that of its companion, the Lunar Reconnaissance Orbiter, which remains in lunar orbit, will allow scientists to provide more specific results on the composition, quantities, and sources of the water. Results from Earth-based observations are expected in the spring and should add to this new wealth of data. “We’re really not done yet and we’ll keep you informed,” said Wargo. In the meantime, scientists are working to understand this new image of the Moon, “it’s not Apollo’s Moon” said Delory, “it’s our Moon.”