New data and images from NASA's new moon orbiter — the first
in more than a decade — have revealed tentative signs of lunar water ice, the
space agency announced Thursday.
The powerful Lunar
Reconnaissance Orbiter, or LRO, has successfully completed its testing and
calibration phase and entered its mapping orbit of the moon. The spacecraft's
instruments have also made measurements of space radiation in the lunar
environment and have found more widespread possible signatures of water on the
moon.
"The LRO mission already has begun to give us new data
that will lead to a vastly improved atlas of the lunar south pole and advance
our capability for human exploration and scientific benefit," said Richard
Vondrak, LRO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.
The first results from LRO's Lunar Exploration Neutron
Detector, or LEND, indicate that permanently shadowed and nearby regions may
harbor water ice and hydrogen. LEND relies on a decrease in neutron radiation
from the lunar surface to indicate the presence of water or hydrogen.
One big finding so far from LEND is that "the hydrogen
is not confined to permanently shadowed craters," Vondrak said. Team
members want more observations to confirm these findings and determine how significant
they are and how to interpret them.
"The power of LRO is that we're not just sending one
instrument, like LEND, to look for hydrogen, we're characterizing fully"
the lunar south pole, Vondrak said.
Jump on science
The spacecraft, launched toward
the moon on June 18, is in good shape and set to begin its scientific
mission in earnest, mission managers reported.
"The LRO instruments, spacecraft, and ground systems
continue to operate essentially flawlessly," said Craig Tooley, LRO
project manager at Goddard.
Mission scientists were able to get a jump on some of the
science objectives during the commissioning phase of the instrument and get some
results that mission officials emphasize are preliminary.
"But some of them are really intriguing too," said
Michael Wargo, chief lunar scientist at the Exploration Systems Mission
Directorate, NASA Headquarters in Washington, D.C.
The powerful $540 million orbiter,
which is about the size of a Mini Cooper car, is on a one-year mission to seek
out potential landing sites for future astronauts, as well as build new maps of
the moon's surface, temperature extremes and radiation environment. It will also
hunt for water ice in the permanently shadowed craters of the moon's south
pole. A source of water ice on the moon would be a boon to any future moon
bases because it could be melted for water and hydrogen for fuel could be
extracted from it.
First results
In addition to the initial LEND results, data from LRO's
Lunar Orbiter Laser Altimeter, or LOLA, used to map elevation indicates that
exploring the moon's south pole will be challenging because the terrain is very
rough. Some of the crater slopes that LOLA has measured are relatively steep
and would be difficult to drive a truck or car over, let alone a moon rover,
said David Smith, LOLA principal investigator at Goddard.
That roughness is probably a result of the lack of
atmosphere and absence of erosion from wind or water, Smith said. LOLA has
already mapped a good portion of the lunar south pole, he added.
LRO's other instruments also are providing data to help map
the moon's terrain and resources.
The probe's Diviner instrument for mapping temperature
revealed large, frigid expanses in the permanently shadowed craters are about
minus 400 degrees Fahrenheit (minus 240 Celsius), "which is extremely cold
and is much colder than the temperature needed to trap a volatile, such as
water," Vondrak said. In fact, these permanently shadowed regions
"are perhaps the coldest part of the solar system," he added.
The team will monitor seasonal changes in the temperature
over the course of the mission. Currently, the lunar south pole is heading into
summer.
The moon up close
The Lunar Reconnaissance Orbiter Camera is providing
high-resolution images of permanently shadowed regions while lighting
conditions change as the moon's south pole enters lunar summer.
"By the end of this mission, we will fully characterize
and get he best possible information we can on the existence of hydrogen"
on or below the lunar surface, Vondrak said.
But, "if you really want to find out what's below the
surface, you have to touch the surface," Vondrak said, which is where LRO's
companion mission, the Lunar Crater Observation and Sensing Satellite, comes in
LCROSS will impact the moon's south pole on Oct. 9 to
generate debris that can be analyzed for signs of water. LCROSS'
target crater, called Cabeus A, was announced by NASA last week.
Meanwhile, LRO's Cosmic Ray Telescope for the Effects of
Radiation instrument is exploring the lunar radiation environment and its
potential effects on humans during record high, "worst-case" cosmic
ray intensities accompanying the extreme solar minimum conditions of this solar
cycle.
LRO has sent back several batches of images, taken by LROC,
before this newest set, including a region known as Mare Nubium (or Sea of Clouds), the Apollo
11 landing site, and the tracks from a difficult Apollo spacewalk.
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