Hello
BioBLASTers:
As
you recall, we have an orientation activity on the BioBLAST® CD-ROM
that has
By
the way, have you all received your CD-ROMS?
Best
regards,
--Laurie--
Resent-Sender:
ames-releases-request@lists.arc.nasa.gov
David
Morse
Oct. 13, 1999
NASA Ames Research Center, Moffett Field, CA
Phone: 650/604-4724 or 604-9000
E-mail: dmorse@mail.arc.nasa.gov
Becky
Rische
University of Texas at Austin
(Phone: 512/471-7272)
RELEASE:
99-63
NO
WATER ICE DETECTED FROM LUNAR PROSPECTOR IMPACT
Research
group leaders from the University of Texas at Austin announced their results
today at the annual meeting of the American Astronomical Society's Division for
Planetary Sciences meeting in Padua, Italy.
In
a low-budget attempt to wring one last bit of scientific productivity from the
low-cost Lunar Prospector mission, NASA worked with engineers and astronomers at
the University of Texas to precisely crash the barrel-shaped spacecraft into a
specific shadowed crater. NASA
accepted the team's proposal based on successful scientific peer review of the
idea and the pending end of the spacecraft's useful life, although the chances
Worldwide
observations of the crash were focused primarily on using sensitive
spectrometers tuned to look for the ultraviolet emission lines expected from the
hydroxyl (OH) molecules that should be a by-product of any icy rock and dust
kicked up by the impact of the 354-pound spacecraft.
"There
are several possible explanations why we did not detect any water signature, and
none of them can really be discounted at this time," said Dr. Ed Barker,
assistant director of the university's McDonald Observatory at UT Austin, who
coordinated the observing campaign.
These
explanations include:
the spacecraft might have missed the target area
the spacecraft might have hit a rock or dry soil at the target site
water
molecules may have been firmly bound in rocks as hydrated mineral
no
water exists in the crater and the hydrogen detected by the Lunar
studies of the impact's physical outcome were inadequate
the
parameters used to model the plume that resulted from the impact
the
telescopes used to observe the crash, which have a very small field
water
and other materials may not have risen above the crater wall or
Although
the crash did not confirm the existence of water ice on the Moon, "this
high-risk, potentially high-payoff experiment did produce several
benefits," said Dr. David Goldstein, the aerospace engineer who led the UT
Austin team. "We now have
experience building a remarkably complex, coordinated observing program with
astronomers across the world; we established useful upper limits on the
properties of the Moon's natural atmosphere, and we tested a possible means of
true 'lunar prospecting' using direct impacts."
Lunar
Prospector was launched on Jan. 6, 1998, from Cape Canaveral Air Station, FL,
aboard an Athena 2 rocket. In March
1998, mission scientists announced their first tentative findings of the
presence of water ice in shadowed craters near the Moon's south and north poles.
Scientists later estimated as much as six billion metric tons of water
ice may be buried in these craters under about 18 inches of soil, in more
concentrated deposits than originally thought.
However, the evidence was indirect, they cautioned, based on reasonable
scientific assumptions given the levels of hydrogen detected, from which water
ice is inferred.
Since
then, Prospector data have also been used to develop the first precise gravity
map of the entire lunar surface. While
the Moon's magnetic field is relatively weak, Prospector has confirmed the
presence of local magnetic fields that create the two smallest magnetospheres in
the Solar System. Another
scientific landmark is the assembly of the first global maps of the Moon's
elemental composition.
The
$63 million Lunar Prospector mission was led by Dr. Alan Binder of the Lunar
Research Institute, Tucson, AZ, and managed by NASA's Ames Research Center in
Moffett Field, CA. The spacecraft
was built by Lockheed Martin Missiles & Space, Sunnyvale, CA.
Other participating organizations included the Department of Energy's Los
Alamos National Laboratory, NM; NASA's Goddard Space Flight Center, Greenbelt,
MD; and Jet Propulsion Laboratory, Pasadena, CA.
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