From: Dale K Stalnaker (Dale.K.Stalnaker@grc.nasa.gov)
Date: Tue May 28 2002 - 14:23:48 EDT

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    >>Date: Tue, 28 May 2002 13:00:27 -0400 (EDT)
    >>From: NASANews@hq.nasa.gov
    >>Sender: owner-press-release@lists.hq.nasa.gov
    >>To: undisclosed-recipients:;@lists.hq.nasa.gov
    >>Donald Savage
    >>Headquarters, Washington May 28, 2002
    >>(Phone: 202/358-1547)
    >>Mary Hardin
    >>Jet Propulsion Laboratory, Pasadena, Calif.
    >>(Phone: 818/354-0344)
    >>Heather Enos
    >>University of Arizona, Tucson, Ariz.
    >>(Phone: 520-621-8279)
    >>RELEASE: 02-99
    >> Using instruments on NASA's 2001 Mars Odyssey
    >>spacecraft, surprised scientists have found enormous
    >>quantities of buried treasure lying just under the surface of
    >>Mars-enough water ice to fill Lake Michigan twice over. And
    >>that may just be the tip of the iceberg.
    >>"This is really amazing. This is the best direct evidence we
    >>have of subsurface water ice on Mars. We were hopeful that we
    >>could find evidence of ice, but what we have found is much
    >>more ice than we ever expected," said William Boynton,
    >>principal investigator for Odyssey's gamma ray spectrometer
    >>suite at the University of Arizona, Tucson.
    >>Scientists used Odyssey's gamma ray spectrometer instrument
    >>suite to detect hydrogen, which indicated the presence of
    >>water ice in the upper meter (three feet) of soil in a large
    >>region surrounding the planet's south pole. "It may be better
    >>to characterize this layer as dirty ice rather than as dirt
    >>containing ice," added Boynton. The detection of hydrogen is
    >>based both on the intensity of gamma rays emitted by
    >>hydrogen, and by the intensity of neutrons that are affected
    >>by hydrogen. The spacecraft's high-energy neutron detector
    >>and the neutron spectrometer observed the neutron intensity.
    >>The amount of hydrogen detected indicates 20 to 50 percent
    >>ice by mass in the lower layer. Because rock has a greater
    >>density than ice, this amount is more than 50 percent water
    >>ice by volume. This means that if one heated a full bucket of
    >>this ice-rich polar soil it would result in more than half a
    >>bucket of water.
    >>The gamma ray spectrometer suite is unique in that it senses
    >>the composition below the surface to a depth as great as one
    >>meter. By combining the different type of data from the
    >>instrument, the team has concluded the hydrogen is not
    >>distributed uniformly over the upper meter but is much more
    >>concentrated in a lower layer beneath the top-most surface.
    >>The team also found that the hydrogen-rich regions are
    >>located in areas that are known to be very cold and where ice
    >>should be stable. This relationship between high hydrogen
    >>content with regions of predicted ice stability led the team
    >>to conclude that the hydrogen is, in fact, in the form of
    >>ice. The ice-rich layer is about 60 centimeters (two feet)
    >>beneath the surface at 60 degrees south latitude, and gets to
    >>within about 30 centimeters (one foot) of the surface at 75
    >>degrees south latitude.
    >>"Mars has surprised us again. The early results from the
    >>gamma ray spectrometer team are better than we ever
    >>expected," said R. Stephen Saunders, Odyssey's project
    >>scientist at NASA's Jet Propulsion Laboratory (JPL),
    >>Pasadena, Calif. "In a few months, as we get into Martian
    >>summer in the northern hemisphere, it will be exciting to see
    >>what lies beneath the cover of carbon dioxide dry-ice as it
    >>"The signature of buried hydrogen seen in the south polar
    >>area is also seen in the north, but not in the areas close to
    >>the pole. This is because the seasonal carbon dioxide (dry
    >>ice) frost covers the polar areas in winter. As northern
    >>spring approaches, the latest neutron data indicate that the
    >>frost is receding, revealing hydrogen-rich soil below," said
    >>William Feldman, principal investigator for the neutron
    >>spectrometer at Los Alamos National Laboratories, New Mexico.
    >>"We have suspected for some time that Mars once had large
    >>amounts of water near the surface. The big questions we are
    >>trying to answer are, 'where did all that water go?' and
    >>'what are the implications for life?' Measuring and mapping
    >>the icy soils in the polar regions of Mars as the Odyssey
    >>team has done is an important piece of this puzzle, but we
    >>need to continue searching, perhaps much deeper underground,
    >>for what happened to the rest of the water we think Mars once
    >>had," said Jim Garvin, Mars Program Scientist, NASA
    >>Headquarters, Washington.
    >>Another new result from the neutron data is that large areas
    >>of Mars at low to middle latitudes contain slightly enhanced
    >>amounts of hydrogen, equivalent to several percent water by
    >>mass. Interpretation of this finding is ongoing, but the
    >>team's preliminary hypothesis is that this relatively small
    >>amount of hydrogen is more likely to be chemically bound to
    >>the minerals in the soil, than to be in the form of water
    >>JPL manages the 2001 Mars Odyssey mission for NASA's Office
    >>of Space Science, Washington. Investigators at Arizona State
    >>University, Tempe, the University of Arizona, Tucson, and
    >>NASA's Johnson Space Center, Houston, operate the science
    >>instruments. The gamma-ray spectrometer was provided by the
    >>University of Arizona in collaboration with the Russian
    >>Aviation and Space Agency, which provided the high-energy
    >>neutron detector, and the Los Alamos National Laboratories,
    >>New Mexico, which provided the neutron spectrometer. Lockheed
    >>Martin Astronautics, Denver, developed and built the orbiter.
    >>Mission operations are conducted jointly from Lockheed Martin
    >>and from JPL, a division of the California Institute of
    >>Technology in Pasadena.
    >>Additional information about the 2001 Mars Odyssey and the
    >>gamma-ray spectrometer is available at /is available on the
    >>Internet at: http://mars.jpl.nasa.gov/odyssey/ and
    >> -end-
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    Dale K. Stalnaker
    NASA/Glenn Research Center
    Power & Propulsion Office
    PHONE: (216) 433-5399
    FAX: (216) 433-2995

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