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Δελτίο Τύπου http://www.nasa.gov/home/hqnews/2009/nov/HQ_09-265_LCROSS_Confirms_Water.html
Nov. 13, 2009
Grey Hautaluoma/Ashley Edwards
Headquarters, Washington
202-358-0668/1756
grey.hautaluoma-1@nasa.gov, ashley.edwards-1@nasa.gov
Jonas Dino
Ames Research Center, Moffett Field, Calif.
650-604-5612
jonas.dino@nasa.gov
RELEASE: 09-265
NASA'S LCROSS IMPACTS CONFIRM WATER IN LUNAR CRATER
MOFFETT FIELD, Calif. -- Preliminary data from NASA's Lunar Crater
Observation and Sensing Satellite, or LCROSS, indicates the mission
successfully uncovered water in a permanently shadowed lunar crater.
The discovery opens a new chapter in our understanding of the moon.
The LCROSS spacecraft and a companion rocket stage made twin impacts
in the Cabeus crater Oct. 9 that created a plume of material from the
bottom of a crater that has not seen sunlight in billions of years.
The plume traveled at a high angle beyond the rim of Cabeus and into
sunlight, while an additional curtain of debris was ejected more
laterally.
"We're unlocking the mysteries of our nearest neighbor and, by
extension, the solar system," said Michael Wargo, chief lunar
scientist at NASA Headquarters in Washington. "The moon harbors many
secrets, and LCROSS has added a new layer to our understanding."
Scientists long have speculated about the source of significant
quantities of hydrogen that have been observed at the lunar poles.
The LCROSS findings are shedding new light on the question with the
discovery of water, which could be more widespread and in greater
quantity than previously suspected. If the water that was formed or
deposited is billions of years old, these polar cold traps could hold
a key to the history and evolution of the solar system, much as an
ice core sample taken on Earth reveals ancient data. In addition,
water and other compounds represent potential resources that could
sustain future lunar exploration.
Since the impacts, the LCROSS science team has been analyzing the huge
amount of data the spacecraft collected. The team concentrated on
data from the satellite's spectrometers, which provide the most
definitive information about the presence of water. A spectrometer
helps identify the composition of materials by examining light they
emit or absorb.
"We are ecstatic," said Anthony Colaprete, LCROSS project scientist
and principal investigator at NASA's Ames Research Center in Moffett
Field, Calif. "Multiple lines of evidence show water was present in
both the high angle vapor plume and the ejecta curtain created by the
LCROSS Centaur impact. The concentration and distribution of water
and other substances requires further analysis, but it is safe to say
Cabeus holds water."
The team took the known near-infrared spectral signatures of water and
other materials and compared them to the impact spectra the LCROSS
near infrared spectrometer collected.
"We were able to match the spectra from LCROSS data only when we
inserted the spectra for water," Colaprete said. "No other reasonable
combination of other compounds that we tried matched the
observations. The possibility of contamination from the Centaur also
was ruled out."
Additional confirmation came from an emission in the ultraviolet
spectrum that was attributed to hydroxyl, one product from the
break-up of water by sunlight. When atoms and molecules are excited,
they release energy at specific wavelengths that can be detected by
the spectrometers. A similar process is used in neon signs. When
electrified, a specific gas will produce a distinct color. Just after
impact, the LCROSS ultraviolet visible spectrometer detected hydroxyl
signatures that are consistent with a water vapor cloud in sunlight.
Data from the other LCROSS instruments are being analyzed for
additional clues about the state and distribution of the material at
the impact site. The LCROSS science team and colleagues are poring
over the data to understand the entire impact event, from flash to
crater. The goal is to understand the distribution of all materials
within the soil at the impact site.
"The full understanding of the LCROSS data may take some time. The
data is that rich," Colaprete said. "Along with the water in Cabeus,
there are hints of other intriguing substances. The permanently
shadowed regions of the moon are truly cold traps, collecting and
preserving material over billions of years."
LCROSS was launched June 18 from NASA's Kennedy Space Center in
Florida as a companion mission to the Lunar Reconnaissance Orbiter,
or LRO. Moving at a speed of more than 1.5 miles per second, the
spent upper stage of its launch vehicle hit the lunar surface shortly
after 4:31 a.m. PDT Oct. 9, creating an impact that instruments
aboard LCROSS observed for approximately four minutes. LCROSS then
impacted the surface at approximately 4:36 a.m.
LRO observed the impact and continues to pass over the site to give
the LCROSS team additional insight into the mechanics of the impact
and its resulting craters. The LCROSS science team is working closely
with scientists from LRO and other observatories that viewed the
impact to analyze and understand the full scope of the LCROSS data.
For information about LCROSS, visit:
http://www.nasa.gov/lcross
