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October
21, 2010 -NASA missions uncover the moon's buried treasures
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Nearly
a year after announcing the discovery of water molecules
on the moon, scientists now reveal new data uncovered by
NASA's Lunar CRater Observation and Sensing Satellite, or
LCROSS, and Lunar Reconnaissance Orbiter, or LRO.
-- the
lunar soil within shadowy craters is rich in useful materials,
and the moon is chemically active and has a water cycle.
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Nearly
a year after announcing the discovery of water molecules on the
moon, scientists Thursday revealed new data uncovered by NASA's
Lunar CRater Observation and Sensing Satellite, or LCROSS, and
Lunar Reconnaissance Orbiter, or LRO.
The
missions found evidence that the lunar soil within shadowy craters
is rich in useful materials, and the moon is chemically active
and has a water cycle. Scientists, including co-author Maria Zuber,
head of MIT’s Department of Earth, Atmospheric and Planetary Sciences,
also confirmed the water was in the form of mostly pure ice crystals
in some places. The results are featured in six papers published
in the Oct. 22 issue of Science.
"NASA
has convincingly confirmed the presence of water ice and characterized
its patchy distribution in permanently shadowed regions of the
moon," said Michael Wargo, chief lunar scientist at NASA Headquarters
in Washington. "This major undertaking is the one of many steps
NASA has taken to better understand our solar system, its resources,
and its origin, evolution, and future."
The
twin impacts of LCROSS and a companion rocket stage in the moon's
Cabeus crater on Oct. 9, 2009, lifted a plume of material that
might not have seen direct sunlight for billions of years. As
the plume traveled nearly 10 miles above the rim of Cabeus, instruments
aboard LCROSS and LRO made observations of the crater and debris
and vapor clouds. After the impacts, grains of mostly pure water
ice were lofted into the sunlight in the vacuum of space.
"Seeing
mostly pure water ice grains in the plume means water ice was
somehow delivered to the moon in the past, or chemical processes
have been causing ice to accumulate in large quantities," said
Anthony Colaprete, LCROSS project scientist and principal investigator
at NASA's Ames Research Center in Moffett Field, Calif. "Also,
the diversity and abundance of certain materials called volatiles
in the plume, suggest a variety of sources, like comets and asteroids,
and an active water cycle within the lunar shadows."
Volatiles
are compounds that freeze and are trapped in the cold lunar craters
and vaporize when warmed by the sun. The suite of LCROSS and LRO
instruments determined as much as 20 percent of the material kicked
up by the LCROSS impact was volatiles, including methane, ammonia,
hydrogen gas, carbon dioxide and carbon monoxide.
The
instruments also discovered relatively large amounts of light
metals such as sodium, mercury and possibly even silver.
Scientists
believe the water and mix of volatiles that LCROSS and LRO detected
could be the remnants of a comet impact. According to scientists,
these volatile chemical by-products are also evidence of a cycle
through which water ice reacts with lunar soil grains.
LRO's
Diviner instrument gathered data on water concentration and temperature
measurements, and LRO's Lunar Exploration Neutron Detector mapped
the distribution of hydrogen. This combined data led the science
team to conclude the water is not uniformly distributed within
the shadowed cold traps, but rather is in pockets, which may also
lie outside the shadowed regions.
The
proportion of volatiles to water in the lunar soil indicates a
process called "cold grain chemistry" is taking place. Scientists
also theorize this process could take as long as hundreds of thousands
of years and may occur on other frigid, airless bodies, such as
asteroids; the moons of Jupiter and Saturn, including Europa and
Enceladus; Mars' moons; interstellar dust grains floating around
other stars and the polar regions of Mercury.
"The
observations by the suite of LRO and LCROSS instruments demonstrate
the moon has a complex environment that experiences intriguing
chemical processes," said Richard Vondrak, LRO project scientist
at NASA's Goddard Space Flight Center in Greenbelt, Md. "This
knowledge can open doors to new areas of research and exploration."
By
understanding the processes and environments that determine where
water ice will be, how water was delivered to the moon and its
active water cycle, future mission planners might be better able
to determine which locations will have easily-accessible water.
The existence of mostly pure water ice could mean future human
explorers won't have to retrieve the water out of the soil in
order to use it for valuable life support resources. In addition,
an abundant presence of hydrogen gas, ammonia and methane could
be exploited to produce fuel.
LCROSS
launched with LRO aboard an Atlas V rocket from Cape Canaveral,
Fla., on June 18, 2009, and used the Centaur upper stage rocket
to create the debris plume. The research was funded by NASA's
Exploration Systems Missions Directorate at the agency's headquarters.
LCROSS was managed by Ames and built by Northrop Grumman in Redondo
Beach, Calif. LRO was built and is managed by Goddard.
Written
by: NASA
For
more information about LCROSS, a complete list of the papers and
their authors, visit: http://www.nasa.gov/lcross For more information
about the LRO mission, visit: http://www.nasa.gov/lro
contact:
Michael Braukus, NASA (Washington, D.C. headquarters)
email: michael.j.braukus@nasa.gov phone: 202-358-1979
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