NASA Missions Uncover The Moon's Buried Treasures
WASHINGTON -- 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 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.
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
Source: NASA
